Van front suspension thoughts

[\\'anderer]

After seeing ujointclothing's van pictures I am wondering. How difficult would it be to convert from my pathfinder conversion, coil front suspension to some good 'ol leafs. The pathfinder conversion looks ok, but seems overly complicated and limited in suspension travel. Any thoughts?

[Bob_Sheaves]

After seeing ujointclothing's van pictures I am wondering. How difficult would it be to convert from my pathfinder conversion, coil front suspension to some good 'ol leafs. The pathfinder conversion looks ok, but seems overly complicated and limited in suspension travel. Any thoughts?
Are you talking longitudinal leaf springs or transverse, like this:

http://www.imagehosting.com/out.php/i595845_62239700000003.jpg

Ignore the rest of that design-it is just for a demo.

Best regards,

Bob Sheaves
CEO
catNET Incorporated
http://www.catnetsolutions.com

[Grim Reaper]

Ford van?
Pictures of what you have?

Stick with the coils. It is easier to fix your wheel travel complaints then fix the problems you will create by going to leaf and trying to figure out how to get the steering to work (the leafs will be in the way of the drag link). The ride is easier to taylor with coils. I assume this has a Ford Radius arm set up. Longer arms are readily available and with the correct choice of springs you can get some respectable wheel travel out of them and still handle and ride well on the hwy.

[ujoint]

What year is the van? ---- I'm pretty sure Pathfinder stopped making conversions in 91 or so. I make the kit that is on my van, for the 92 & up Ford vans. It can be done, but it will have to be fabricated.

[ujoint]

that's a Sportsmobile conversion.

[\\'anderer]

My van is a 1979 Pathfinder. I will post some pics later today.

[ujoint]

I had a 78 Pathfinder that I converted to leafs a few years ago, so it can be done.

[\\'anderer]

I had a 78 Pathfinder that I converted to leafs a few years ago, so it can be done.

How was the ride after the conversion, and was it worth the trouble.
what were your reasons for converting it?

I plan on taking it on longer trips, so road manners are also a concern .

http://inlinethumb49.webshots.com/2736/2135323960013949235S600x600Q85.jpg (http://good-times.webshots.com/photo/2135323960013949235pcKoFS)

Below are some pics. The first thing I notice is the front track bars and the axle form a trapezoid, if the van goes through a dip, besides the rubber parts the suspension compression will push on the bars and push up on the crossmember.
It looks like I only get real suspension travel if only one side compresses, not both.
http://inlinethumb09.webshots.com/3080/2155929800013949235S600x600Q85.jpg (http://good-times.webshots.com/photo/2155929800013949235LpCjas)
http://inlinethumb42.webshots.com/4073/2038111620013949235S600x600Q85.jpg (http://good-times.webshots.com/photo/2038111620013949235vgbTou)

http://inlinethumb63.webshots.com/2622/2787909820013949235S600x600Q85.jpg (http://good-times.webshots.com/photo/2787909820013949235hOSsvX)

I have the new rubber parts to repair this
http://inlinethumb38.webshots.com/2981/2365571840013949235S600x600Q85.jpg (http://good-times.webshots.com/photo/2365571840013949235CdujXi)

[Grim Reaper]

:eek:


I was expecting to see an off the shelf 100 series ford axle with off the shelf radius arms and pan hard like my buddies 79 Bronco.

The pan hard set up is unique thats for sure and the big problem with wheel travel. If you could get it to a single pan-hard respectable wheel travel is no problem with a spring change. The problem is the cross-member is in the way. I suspect that cross-member is in that position to allow clearance to remove the engine. If that cross member could be changed and then switch to the Bronco style drag link and tire rod it could work.

Personally I would be tempted to modify the cross-member to keep the coils. Just having a heard time on telling how much room is between the drag link and cross member.

Something more like this on the late 70's 100's http://77cj.littlekeylime.com/Dana44.htm The steering drag link is missing off the top left picture.

If you were to use that style drag link and tie rod then go to a single pan hard/ Track bar that mounts off the frame up near the steering box that would get rid of that double track bar that is binding.

The goal is to have the drag link and the track bar roughly parallel and same length. That will limit bump steer. Other then the pan hard bar and frame mount I think the rest of the parts would be off the shelf parts off a late 70's 4x4 ford 100 series. If you want to get a lot more wheel travel then swap to longer radius arms and a bearing on the passenger side lower spring mount and it would get a LOT of flex. Take some custom fabrication on the arms but can be done.

http://www.jackit.com/manufacturer/cage/cage_ford_bronco_f150.html


The worst part about converting to leaf springs will be the steering and getting the clearance on the drag link and leaf pack. If you go spring under it would be pretty easy. Spring over you may need a little more lift and convert the knuckles to high steer ($$$$).

[ujoint]

I had that same style front end on my 78. I removed the driver side trac bar, and it freeded up the front end quite a bit. The downside is that those dual trac bars also act as a sort of sway bar, so there will be some weird handling issues. I got used to it, but it felt really crazy at first. ---- I completed the leaf spring swap for several reasons. I wanted 1 ton axles, and I wanted to lift the van for larger tires. The ride was OK, I had a 4" spring with a 4 inch "push" forward on the center pin. I didn't run a trac bar, and I had no steering issues, running crossover steering. This is a pic of my old van after the leaf spring conversion.



http://www.ujointclothing.com/azusa/large_images/22.jpg

If you want to keep the coils & not lift the van any higher, update the suspension with new bushings and have someone fabricate a single trac bar using an adjustable unit from Donahoe or Fabtech. ----Chris

[\\'anderer]

I am still leaning toward leafs. The front axle sits back in the wheel well and causes my tires to rub. The door is so close to the wheel well trimming is not an option. Moving the axle forward a touch and a small lift would be nice.

[ntsqd]

I think it was Camburg Engineering that set up a 4wd van for Baja Chase duty. Would be worth calling Jerry and asking about the situation.

That funky tracbar arrangement is a problem. I've seen that b4 & wondered if that is due to the steering design? (Bob? designer name escapes me) Matters not, Early Broncos used that steeering design and a single tracbar very successfully.
In any case going to a proper tracbar set up by someone who understands what has to happen will aid wheel travel & ride quality tremendously.

Leaves are generally easy and cheap. However, for the same or less effort with coils you will get much better ride quality. After getting the tracbar situation sorted out I'd look into longer radius arms. Those two mods, combined with some monotube shocks will reap large gains.

[pete.wilson]

Hey

As for vans; if one did not need the four wheel drive but still wanted a bit more altitude, where can you go and find taller springs for the front and leafs for the back. I was looking at a nice custom 96 Ford E150. One could always put in a limited slip or a full locker if needed. It was only $3000 with a very nice interior and a 351, 99k miles. Thoughts

[ntsqd]

Not sure when Ford abandoned the Twin-I-Beam/Twin-Traction-Beam front end, but '96 is getting close.

I've no familiarity with the later A-Arm stuff. Might talk to Dixon Bros (http://www.dixonbrosracing.com/main.htm)about the project as they are familiar with them.

If a TIB then lift springs for a 4wd truck are the most likely first source. Pay attention to the spring rates as they compare to stock, which will likely take some parts book digging and/or some physical measurements & calcs.
The springs are the relatively easy part of the front end. With a TIB or a TTB a properly done lift corrects for caster and camber by modifying the beams & radius arms rather than moving their mounting points down. Moving the mounts puts huge stresses on the brackets & frame. OK for mall cruiser, NFG for anything else. The two biggest names in TTB/TIB development are:
Autofab (http://autofab.com/)

Spirit Racing (http://www.spiritracing.com/)

In any case Deaver Spring (http://www.deaverspring.com/) has developed a good reputation for leaf springs in the desert racing world. Though just about any leaf spring vendor can supply what you are looking for.

[Photog]

Mike,
After looking at your photos, under your van, it looks like the odd trac-bars prevent the axle from moving straight up. Allowing only one side or the other to move (as you said). Good flex. It looks like there is a cross member above the axle, that would get crashed by the axle, if the trac bar design were changed. So; if you change the trac-bar design, you may also need to change the cross-member design.

You definitely need new bushings everywhere.

As for moving the axle forward, that would be easy, with a slightly longer set of radius arms. 1" forward would make loads of room behind the tire, and you may not need to change anything else. Even your bumpstops would line up better (I would add a flat pad on the axle, for the bumpstop to hit). Then you might need to trim the front of the wheel well, and possibly the bumper.

[ujoint]

If you move the axle forward with the current steering, I'm afraid it's going to bind up & possibly hit the diff cover. Also, there isn't much room to fab a single trac bar from the drivers side frame rail to the pass side of the axle. If you just remove the drivers side trac bar, the van is gonna handle really weird, I know this because I did it on my Pathfinder. The solution to that is to install a stronger joint @ the axle end, something that doesn't have the "give" of the current bushing. You can see what I mean with about 10 minutes of work (remove the drivers side trac bar).

[Photog]

You could be correct about the steering hitting the diff-cover. The photos don't show how much/little space there is availble. I would change the steering linkage design, to a cross over style, with the steering-rod connecting into the tierod on the passenger side.

As for making one of the trac-bar bushing into a stronger joint; the current design won't work, without a fair amount of flex in the joints. When the axle rises straight up, those joints need to collapse. If one is stronger, the axle will move sideways, as it comes up. If they are both stronger, the axle won't move up. It is triangulated.

Other options: Take out the track-bars, put a bumpstop on the cross-member for the axle/pumpkin stop. Build a longer, single, trac-bar, probably requiring a coupl custom brackets for the ends (frame & axle). Make the trac-bar the same length as the new steering-rod, to reduce bump-steer. The track bar would need to be attached to the frame on the driver's side, and axle on the passenger side.

edit: A bumpstop on the cross member might cause the axle to be bent, with a hard hit. Might not be an option.

[ntsqd]

Do those rubber donuts on the axle ends of the trac-bars have a center sleave, or can you tighten them to where ever you want?

If no sleave I would suggest, as others have, removing the driver's side bar, and then tighten that passenger side trac-bar nut. Try that as an experiment and see how it rides. For the moment ignore how it steers.
Even if there is a limiting sleave I'd still do the experiment.

FWIW I'd leave that steering design alone. Ford spent a lot of time & money to come up with that design to achieve at least one worthwhile goal, toe-in in droop. Besides, the steering isn't the issue and going to conventional cross-over steering isn't going to buy you much.

Not sure how possible it would be, but if in search of wheel travel I'd be eyeing that cross member with the intent to replace it with a fabricated unit of more differential clearance.

[ujoint]

That steering is from a TTB ford, Pathfinder probably only used it because it was available off the shelf & cheap at the time. A true "crossover" will bring the drag link up high, not needed for this rig, and would require custom machining to the pass side steering knuckle. A straight tie rod with the drag link attached would be better, as stated above, but good luck finding a good donor application. ---The bushings at the ends of the trac bars are basically the same as the radius arms, there isn't a sleeve. You can tighten them until they bust, and the axle would be off centered. Clearance is very very tight near the steering box, so a trac bar mount there will be hard, and you also have to worry about the stress on the accordian section of the frame. An additional brace to the pass side frame rail would be needed. Pathfinders are known to already have frame cracking issues near the gearbox, so the whole area will need some bracing. Just bite the bullet and go leaf spring dana 60!!!!!!!!!!!!!!!! You know that's what you want!!!!!!!!!!!!!!!!!!!!

[ujoint]

Photog----

When the axle rises straight up, those joints need to collapse.


what do you mean?

[ntsqd]

snippage......
A straight tie rod with the drag link attached would be better, as stated above,
Why do you think that? Rock-crawlers seem to be the only folks who have on-going troubles with that system and it has some decided pluses for other applications.


The bushings at the ends of the trac bars are basically the same as the radius arms, there isn't a sleeve. You can tighten them until they bust, and the axle would be off centered.
Presumably then one could drive the vehicle with these overly tight as test of what loosing one of the trac-bars would do for ride quality. Surely wouldn't suggest it a permanent fix.


Just bite the bullet and go leaf spring dana 60!!!!!!!!!!!!!!!! You know that's what you want!!!!!!!!!!!!!!!!!!!!
I sure don't want the extra unsprung mass of a D60 when I'm not rock-crawling the truck and a well set-up coil system can't be touched for ride quality by the best of a leaf sprung system, particularly in a Van where you're sitting right on top of the axle. I have leaves under the front of the Sub right now. They are an obscure Rancho Pre-Runner K5 spring that work very well, but I know that I can't run with a coil sprung truck. It just isn't going to happen. If I ever go to a bigger front diff or tire of the ride of the leaves it will be an F-250 TTB on coils & radius arms that gets stuffed under there.

[Photog]

Looking at how everything is connected, the axle and two trac-bars makes a triangle. If the trac-bars had bearings on both ends, the triangle would be solid, and the axle could not rise straight up. It would piviot around the point on the cross-member, where the trac-bars connect.

As it is built now, the ends of the trac-bars have bushings (like the radius arms). As the front end rises or falls, these bushings are compressed. If they could not compress, the axle would not move up & down; but only pivot. These bushings probably need to be fairly soft, to function properly. I suspect they should not be tightened down too much, either.

For a rock crawler, the axle may not need to move up & down much; but it would need to pivot, and articulate. On a street and off-road vehicle, the axle must not only articulate; but also move straight up & down. Consider driving through a "Dip". The whole suspension needs to move up, as a unit.

Does this make more sense?:)

[Photog]

There certainly isn't much room under that van, to build up the suspension; but I would make an attempt at improving the existing coil system.

Modify the steering, and trac-bar, to eliminate the issues with the existing system.
A) The trac bars could be replaced with an "A-arm axle locator" coming from behind the front axle. Many folks have used these on rear suspensions.
B) The existing steering linkage causes bump steer, and the toe angle changes as the axle moves up and down. That is why I like the single tie-rod between the knuckles, on a straight axle suspension.

The remaining problem, is how to prevent the axle from rising up and hitting the cross-member, and still allow for articulation.

[Photog]

Solutions for the cross-member problem.

A) Replace the cross-member with a custom piece, that is behind the front axle. Might have to add a small cross-member in front also.

or

B) Put enough lift into the suspension, to give the axle more room to move.

or

C) Move the axle forward, away from the cross-member, and work around the steering linkage issues this causes.

or

D) a combination of a little of each.

[ntsqd]

The toe-in in droop is an intentional result. It promotes stability and a desire for the vehicle to want to go straight when the front end is light. I would not eliminate this just 'because'.

Bump-steer isn't necessarily a villain. Depending on when & where it can be beneficial. What happens is that the steering geometry is developed for a specific ride height and all is good. Then we come along and want more ride height. Suddenly the steering is out of it's design envelope and the design, rather than the modifier, is the villain. Not easily done, but were the ride height change properly done the stock steering design's traits would be maintained.

The way I see it the first thing is to determine what the ride quality is w/o the left side trac-bar. It is the villain. Obviously the trac-bar will need to have a similar arc as whatever the eventual draglink's arc of travel is, but for the immediate future I think identifying the villains and removing them for testing is the priority. Then how to fix it within the desired goals and fabrication skills available can be discussed.

[Photog]

I like your thinking process. Most folks don't think that far down the trail. You are correct about changing ride-height that then changes suspension geometry. It isn't a design problem, unless you need massive travel (off-road racer). As for toe settings, you normally want a slight toe-in. Toe out almost always causes steering problems such as: hunting, wandering, wind steering, etc. A stable toe setting seems more desireable.

So; what is the desired set-up with this rig? Axle forward (fender well room), stable on the freeway, stable off road. How do we get there from here?:rappel:

In making the necessary modifications to do this, do they want to improve on some of the issues of the existing system?:Mechanic:

The steering could be improved with a lowered pitman arm, and still function within the suspension travel envelope. 1" longer radius arms to improve tire space in fender well (this may cause secondary issues). There must be a better way of locating the axle than those two trac-bars, above the axle. AND NEW BUSHINGS AND BUMPSTOPS.:shakin:

[ntsqd]

My goals would be:

1) Ride Quality. Trac-bar design appears to be the villain. Testing should prove or disprove this.

2) Tire Clearance. Slightly longer radius arms or moving radius arm brackets or spacing the existing arms forwards depending on fab skills available & desired level of involvement.

3) Optimize wheel travel. Could be part of 1).

Order of Events:

1) Move/change/build radius arms. Everything else hinges on where the axle is.

2) Decide on steering design type. Fab as necessary. Reinforce steering box mounting, to opposite frame rail and/or engine x-member if deemed necessary.

3) Single Trac-bar system fabrication.

4) Damper mounts, if needed, to employ quality dampers. The closer you are to an axle the more pronounced it's bad ride qualities will be.

[ujoint]

I've done the trac bar test!! The van will be all over the road, the bushings have too much give. It may be better with a sway bar. --- Also, I love how everyone bases all leaf spring suspension on the 73-87 GM's. Those springs are so short they will never ride good. I invite anyone to ride in my van and tell me it rides like crap. A straight tie rod is better because there are less joints to wear and cause steering slop/shakes. ---Ford TTB's are horrible for keeping alignment, causing nothing but headaches & bad tire wear. I also want the assurance that I have a Dana 60 under the front end so I know that I'll get home. What's the weight savings over a Dana 44? Is it really worth it?





Why do you think that? Rock-crawlers seem to be the only folks who have on-going troubles with that system and it has some decided pluses for other applications.


Presumably then one could drive the vehicle with these overly tight as test of what loosing one of the trac-bars would do for ride quality. Surely wouldn't suggest it a permanent fix.


I sure don't want the extra unsprung mass of a D60 when I'm not rock-crawling the truck and a well set-up coil system can't be touched for ride quality by the best of a leaf sprung system, particularly in a Van where you're sitting right on top of the axle. I have leaves under the front of the Sub right now. They are an obscure Rancho Pre-Runner K5 spring that work very well, but I know that I can't run with a coil sprung truck. It just isn't going to happen. If I ever go to a bigger front diff or tire of the ride of the leaves it will be an F-250 TTB on coils & radius arms that gets stuffed under there.

[ujoint]

Any vehicle with a trac bar has an arc that the axle moves under articulation. The flatter the trac bar angle, the less the arc. I thought that you were saying the trac bar needs to have some sort of slip in it.?.





Looking at how everything is connected, the axle and two trac-bars makes a triangle. If the trac-bars had bearings on both ends, the triangle would be solid, and the axle could not rise straight up. It would piviot around the point on the cross-member, where the trac-bars connect.

As it is built now, the ends of the trac-bars have bushings (like the radius arms). As the front end rises or falls, these bushings are compressed. If they could not compress, the axle would not move up & down; but only pivot. These bushings probably need to be fairly soft, to function properly. I suspect they should not be tightened down too much, either.

For a rock crawler, the axle may not need to move up & down much; but it would need to pivot, and articulate. On a street and off-road vehicle, the axle must not only articulate; but also move straight up & down. Consider driving through a "Dip". The whole suspension needs to move up, as a unit.

Does this make more sense?:)

[ntsqd]

I've done the trac bar test!! The van will be all over the road, the bushings have too much give.
Which is why I was suggesting that the nut be tightened more and was specific about stating that this is a test and not a cure.


Also, I love how everyone bases all leaf spring suspension on the 73-87 GM's. Those springs are so short they will never ride good. I invite anyone to ride in my van and tell me it rides like crap.
Not based of off, used as a point of reference. BTW, mine is a '91
I also have an '84 yota 4x4. It works exceptionally well. Most who ride in it comment on how smooth those leaves work.
Still, there is no way, NONE, that I can keep up with a coil sprung or torsion bar sprung truck for very long w/o really beating on the truck. BT, DT, have the cracks to prove it.


A straight tie rod is better because there are less joints to wear and cause steering slop/shakes.
There is no difference in the total number of TRE's in the system. There is a considerable difference in each system's road behavior.
No argument that a straight drag link and tie rod are preferable, however keep in mind that the Ford design is primarily in tension and tension wants to straighten out those bends, not permanently bend the member. Compression only really happens when rock crawling and a tire is forced to turn into something, or when backing up.


---Ford TTB's are horrible for keeping alignment, causing nothing but headaches & bad tire wear.
That bad tire wear is b/c Ford never put enough damping on the system not necessarily b/c the alignment was off. Too many desert race trucks have been successful to outright dominating of their class to say the design is poor. The execution of the design can be fixed, and he's not considering such a thing - I am.


I also want the assurance that I have a Dana 60 under the front end so I know that I'll get home. What's the weight savings over a Dana 44? Is it really worth it?
Yes, it is to me. One pound of unsprung is roughly equal to ten pounds of sprung weight in vehicle performance. So that 100 lbs difference is too much to me.

We're probably going to have to agree to disagree. :)

[Photog]

This is a long one. By the way, is Mike following this, or is this just an interesting discussion on suspension design?

From a design and performance point of view; what is the weight of one of these vans, when loaded for a trip? The Dana 44 & Dana 60 are designed for two different load and torque ratings.

Judging by the photographs, UJoint's van uses the 4X4 function in severe conditions. Per Mike's requirements, it does not seem like his van will be used in such a severe fashion. Unless the weight on the front axle is to high for the Dana44, I'm sure it will do a fine job, as a front axle. A Dana 60 might be necessary for the rear axle.

As for leaf spring ride quality: the long leaves definitely improve the ride quality. The soft springs are not usually suitable for carrying a load. This would bring us back to weight on the front axle. How much does the front axle load change, when the van is empty or loaded for a trip? If the weight is fairly stable, then design the leaf system for comfort, at the typical load. If it were a sports car, off-road racer, or luxury car, I would NOT want a leaf spring front suspension. This van is not in these catagories; so I think it could be set up to be comfortable and functional, either way. The off-road racers that use a straight axle, do use coil spring systems; but they did use leaf spring systems for many, many years. I suspect these van frames were not made for any type of off-road pounding, and the frame should be reinforced, with either suspension type. There are other issues with the leaf setup; such as eliminating the crush can section of the frame, and applying over 1/2 the suspension load to the forward section of the frame. The frame may need reinforced all the way back to the other end of the leaf spring.

Trac-bar angle being flat is usually a good thing, and so are steering-linkage angles. Unfortunately this probably can not be achieved with this van. Trac-bar and steering linkage lengths and angles work well when they are matched to each other. The suspension may move in a slight arc; but the bump steer can be minimized.

:arabia:

[ntsqd]

Just a note on trac-bar & drag link angles; I prefer to set them slightly down towards the axle end. The logic being that if they are flat that you are giving up some of the prime bump-steer free travel. Note that it's usually refered to as "bump-steer" and not "droop-steer". :)
With the slightly downwards angle the system stays within it's sweet spot for more compression distance.

[ujoint]

I've been wondering if Mike's been reading as well. :) No matter the angle (unless it's really ugly), as long as the trac bar & drag link are at the same angle, there shouldn't be ANY bumpsteer. The trac bar should have NO side to side give. Either way, there are plenty of different ways to build a suspension, depending on the needs of the owner. I use my van for everything: daily driver, mtn bike shuttle, camping rig, wheeler, and it works exactly the way I want it. I built hundreds of trucks when I was @ ORU, and I took what I felt to be the best parts from what I'd seen work over the years. I get calls almost daily on 4x4 van conversions, and I always recommend the same things. Durable, cost effective, realistic suspensions.

[ntsqd]

IME it's pretty rare that the drag link and the trac-bar can be both the same length and parallel to each other in both the top view and the side view. Same length & parallel is certainly what you're shooting for, but trying to get textbook perfect alignment btwn them in an existing vehicle is very likely to be difficult at best.

That's not as big of a problem as it might sound like. So long as the travel curves are similar and the starting point of both axle pivots are near the bottom of the region where the curves are the most superimposed, bump steer is not a problem. It is an uncommon driver who can feel a 1/8" divergence in those two arcs, but you can't allow much more than that within the first 3"-4" of up-travel. It's been a while since I looked at it, but I think that Allan Staniforth's "String Computer" technique could probably be used to find the ideal pivot locations of one element given that the other is set.

[\\'anderer]

Sorry I have not replied, I am having Internet connection issues at the moment, but I have read the thread carefully.

Now that I have had some time to think about the van's use. Here is what I need:
The van will be used for expeditions and long camping trips towing my trailer, so it will be on the heavy side.

1. load carrying capacity and safe predictable steering are a must (many miles on road as well as off).

2. A more comfortable ride is important but not at the cost of #1

3. Off road worthiness, will not be extreme, but I would rather overbuild than under estimate the trails I would take it on.


I could remove 1 track bar, and with new bushings, it will probably drive better than it does now but, the track bar is too small for comfort. The front axle sits nicely under the cross member, Moving the axle forward will put it dangerously close to hitting the cross member and steering linkage.

The more I look at the front suspension, the more I see that a "patch" is not the best choice. A complete redesign of the front suspension as a system is the only way to go.

I like the coil spring setup, and removing the small track bars, adding 1 larger bar and crossover steering would make a world of difference. The front end would retain some pathfinder specific parts, namely the bushings that I would rather do away with.


Just bite the bullet and go leaf spring dana 60!!!!!!!!!!!!!!!! You know that's what you want!!!!!!!!!!!!!!!!!!!!

This is still my most likely choice. I really like the simplicity and durability of a front leaf setup. Getting the correct spring rate for my load would help with the ride quality. I think all the modern van conversions use a leaf spring setup
there must be a reason (besides cost) why the coil setup went away.

Besides ride quality complaints, any reason why leafs would not be a good choice for my application?

[ntsqd]

The first big red flag I see is the previously mentioned accordion section of the frame. If you pursue leaves that needs to be torn out and rebuilt since 1/2 the weight of each side will now be carried forward of it and if it doesn't immediately start flexing it soon will.

I can't say how strongly I believe that changing to leaves is not only much more unnecessary work, but also a step backwards in both ulitmate ride quality and in control. And yes, I do think that economics combined with familiarity as being what drives most conversion companies to use leaves.
With cross-over steering and leaf springs it is not all that uncommon to need a trac-bar to counter steering input induced spring deflection. This is more frequent in harder core off road use, but it does happen on the pavement too.

The spring rates you already have must be close to what you need. If not, coil spring rates are much more easily changed than leaf spring rates are. The frame is designed to have the existing load application points, changing to leaves means re-engineering, designing, and modifying the frame.

What I'm reading and seeing tells me that the first step is to address the trac-bar issue and then re-evaluate ride quality and vehicle control. It is my firm belief that a proper trac-bar combined with a quality set of dampers will meet at least 80% of your goals and quite probably do everything you need. I'm not saying that the trac-bar will be easy, but it is fixable for less effort than completely re-designing the front suspension to use leaf springs. If this fabrication is beyond what you're able to do or comfortable with I would suggest contacting a shop that works with Early Broncos, such as West Coast Broncos on Hwy 247 in Yucca Valley, as they work with exactly that front suspension. If you do contact WCB tell Dusty that Thom Singer sent you.
Alternately, Autofab, Spirit Racing, or Camburg Engineering all have extensive history in working with Fords and the TTB and will be familiar with what needs to happen to make it work.

[ujoint]

The accordiansection of the frame is a concern, easily cured by boxing it.
http://www.ujointclothing.com/rigs/images/22.jpg

Sure, a trac bar is always nice to have, but hard to put in a van unless you go with the 86-97 Ford F350 style, which went from the engine x-member to the pass side, very short. I'm not running a trac bar on mine, nor have I put one in any of the conversions I've done. As long as the lift isn't too high and the drag link is as flat as possible, everything is ok. Another thing we have to consider is that everyone has diferent standards of what they consider a "good" or "bad" ride quality. I've driven trucks that I thought rode great, and the customer complained of a horrible ride. I've also driven trucks that I thought rode like a garbage truck on concrete tires, and the customer had no issues, even though I told them I thought it rode bad. So eveyone has different expectations & standards, that's the way it goes. ---- This has turned out to be an awesome thread, tons of fun!!!!!!!!!!

[Photog]

Mike,
Is there any way to get a photo of your suspension from the side (looking straight from one hub to the other)? One of the big issues here is, how much up travel is available for the axle, before it crashes into something?

From the photographs you have already posted, it looks like part of a cross member has been cut out, to make room for the differential, as it rises. This cross member looks to be behind the axle. Is there also one in front of the axle?

The proper photo would clarify this.

Steering linkage can be changed, to make room for the axle to move forward a little. Things like a different pitman arm, etc.

[\\'anderer]

This picture shows the axle directly under the crossmember, the track bars and steering linkage routing

http://inlinethumb49.webshots.com/6768/2040727280013949235S600x600Q85.jpg (http://good-times.webshots.com/photo/2040727280013949235tCHTdG)

This pic. from behind the front axle looking forward and up. Notice how neatly the axle can tuck up into the crossmember. Too far and the axle will hit the oil filter. Available travel upwards is minimal. an inch or so max with with both sides compressed or maybe 3" with just one side compressed. Total suspesnion travel from droop to compression is less than my mountain bike.

http://inlinethumb57.webshots.com/6776/2491484740013949235S600x600Q85.jpg (http://good-times.webshots.com/photo/2491484740013949235NuPWvb)

[Photog]

That looks like a custom crossmember. Probably more beefy than the factory 2WD parts, or mayby a modified 2WD part.

If you modify your coil spring suspension, or go with a leaf system, it looks like you will need to change that crossmember. Replace it with something completely different. Even then, you may need to raise the van an inche or two, to make room for som suspension travel.

You also need to move the axle forward, to make room for the tires. With an A-arm style of axle locator (instead of a trac bar) you would not have any trouble with linkage hitting the axle. It looks like you could move the axle forward a couple inches. Again, this is with a different axle locator (coming from behind the axle), and a modified crossmember.

[ntsqd]

The only reason my Sub is lifted 4" is to get something more than 1" of bump travel. I think that the same sort of thing will hold true here too. There isn't much if any room to increase the bump travel without raising the ride height.

Unfortunately you can not use an A-shape locating member in front suspension unless the drag link is a push-pull & has it's frame end adjacent to the A-link's frame end. An A-arm used with the current steering will result in massive bumpsteer.
I've seen a drag link arranged so that an A-link would work. It's under a semi pre-run '57 Chevy truck somewhere in Nor CA and the linkage required to get it there is rather involved.

[ujoint]

That x-member is the stock 2wd Ford x-member that got hacked up in the typical Pathfinder fashion. There's no reason to change it, waaaaay too much fabrication, and not needed for a project like this.

[Photog]

If the factory crossmember stays, the van will need a suspension lift, to get any type of functional travel.

If the axle gets moved forward, the crossmember will probably need a little more trimming, and maybe a little reinforcement.

Now; as for the axle locator. My thoughts on the A-arm locator are: Mount the A-arm from the rear, attaching to the frame, near the radius arm mounts. The axle already moves through an arc, based on the length of the radius arms; so if the A-arm were designed to match that same arc, it seems like the steering-feel would not be changed from its current condition. The A-arm could come in low, under the driveshaft.

I can see how the there might be some bump steer, because the axle would move through an arc, in a different plane than the steering linkage.

After the lift, you would want to put on a drop-type pitman arm, to reduce the angle of the steering linkage. There would also be less clutter in front of the axle, with the existing trac-bars removed; so other steering changes could be made.

What issues would this type of arrangement cause?

[ntsqd]

I've been pondering whether the trac-bar could be in front of the steering linkage. My best estimate is that it would need to be futher fwd at the frame end than at the axle end, but this should be kept to the barest minimum necessary to keep the plane of the lateral location arc as close to the plane of the long tie-rod's arc as is possible.

I abhor drop pitman arms. They introduce a leverage on the steering box that it really wasn't designed for. Some times you can get away with it, other times they kill the box faster than acceptable.

While I've seen exactly this existing system in the past, we weren't asked to improve that aspect, so I put no effort into what would need to happen. And I'm more and more thinking that it's really going to take a physical inspection to move down the road to improvement.
So I'll repeat my suggestion that WCB (http://www.westcoastbronco.com/) is the most local fab shop that I am willing to suggest as capable of handling this mod. Early Broncos and F-100's have this proposed suspension layout, so WCB is well versed in the intricacies of making them behave as they should. They also have the ability to supply the cross-over type steering in wear parts of suitable size should that still be desired.

[Photog]

I was just thinking about, "If this were my vehicle, what would I do?"

I would take the info put forth in this thread, spend some time under the rig, to understand how it is supposed to work, and then take it to a shop that really knows this type of system, such as WCB (http://www.westcoastbronco.com/). I really have to agree with Thom on this one.

Also, while at the specialty shop (WCB), ask their opinion on a leaf spring system. Maybe the coil system will be straight forward, and meet all the needs, maybe not.

[ujoint]

You guys have to realize that the Pathfinder radius arm suspension setup in this van shares no common parts with a typical Ford radius arm solid axle setup. So yes, a Bronco type system would be a nice setup. The axle will have to be removed, all bracketry cut off, the axle tubes will need to be pulled from the center section, c-forgings will need to be installed over the tubes & reinstalled into the center section, then welded up, and you will need new radius arms & coil mounts. Then you still have to worry about the trac bar, which there never was room for in the first place (the reason for the dual trac bars). So I agree, this would be a nice setup, but you still have a Dana 44 on a vehicle that may be pushing 8000lbs by the time it's said & done. And what about cost? I'd be curious to find out what they'd charge for that conversion.

[G35Vortec454]

I've got to say this is a great front suspension thread/discussion!!!

[Photog]

I don't think I would want the Bronco shop to replace the suspension, with a Bronco copy. What I am suggesting is: The Bronco shop understands how a "Radius Arm" suspension is supposed to function; and they know how to make that type of suspension work in the limited space under a Bronco. They would know what springs (length & spring rate), to gain the desired lift, etc., etc...

I can see a van weighing 8000 lbs, when loaded; but what is the weight on the front axle, I wonder?

[ntsqd]

Concur, I wasn't suggesting that the existing radius arms be replaced with the Ford design radius arms, that would be work for no real gain.

As Photog said, my thinking is that they are well familiar with making the trac-bar/draglink system work in Broncos. This vehicle would not be all that much different.
In the case of WCB, I know that John has been working with Broncos for 20-odd years or more and has likely seen it all. In addition he is a talented fabricator. His new partner Dusty has extensive experience with Early Broncos and has family ties into desert racing Fords. That whole combo plus their relatively close location is what drives my suggestion in talking to them.

[TroySmith80]

It looks like I only get real suspension travel if only one side compresses, not both.
http://inlinethumb09.webshots.com/3080/2155929800013949235S600x600Q85.jpg (http://good-times.webshots.com/photo/2155929800013949235LpCjas)
http://inlinethumb42.webshots.com/4073/2038111620013949235S600x600Q85.jpg (http://good-times.webshots.com/photo/2038111620013949235vgbTou)


This looks like a terrible design! Did pathfinder do it this way all the way through 1991? Or did they revise this somewhere along the way?

[Photog]

I remember this thread, from almost 4 years ago.

Did this suspension ever get sorted out?

[ToyFamily]

You could remove both and add a "pan hard bar" that is as close to equal length and parallel to the drag link and you'll see alot less binding and more travel. much like a 3 link and a panhard suspension set up..or a more recent radius arm and pan hard set up.


Nick

[ntsqd]

Has already been suggested; Post #12 of this thread:
I think it was Camburg Engineering that set up a 4wd van for Baja Chase duty. Would be worth calling Jerry and asking about the situation.

That funky tracbar arrangement is a problem. I've seen that b4 & wondered if that is due to the steering design? (Bob? designer name escapes me) Matters not, Early Broncos used that steering design and a single tracbar very successfully.
In any case going to a proper tracbar set up by someone who understands what has to happen will aid wheel travel & ride quality tremendously.

Leaves are generally easy and cheap. However, for the same or less effort with coils you will get much better ride quality. After getting the tracbar situation sorted out I'd look into longer radius arms. Those two mods, combined with some monotube shocks will reap large gains.

[Keyblazer]

I have an interest in this thread, having a Pathfinder converted front end.

I looked thru the thread, the pics and suggestions, and didnt see something that I wanted to suggest and throw open to discussion...
Its proven, and works on road cars and would be a simple, effective, and I believe easy add...

What about a Watts linkage?
http://en.wikipedia.org/wiki/Watt%27s_linkage

Pic.
http://i260.photobucket.com/albums/ii18/wozzah1975/IMG_0779.jpg

Now normally the linkage is mounted on the axle and the arms to the chassis, but what about keeping the brackets on the axles, and mounting the linkage on the engine crossmember?
I am sure this would work, but offroad?

[ntsqd]

Classically the Watts linkage is used at the rear axle where steering isn't a concern. The problem with using it on a front axle is the drag link. If it is a fore-aft push-pull design then a Watts might work.
Using it with a lateral ("cross-over") drag link would result in massive bump steer as the axle would be going mostly straight up and down, but the axle end of the drag link will travel in an arc.

The simplest to design and describe, if not to build, is a panhard rod that is the same length as the drag link and is installed at the same compound set of angles (front view & top view). Varying the length of the panhard rod from that of the drag link requires adjusting the installed angle and cycling the suspension to check for bump steer.

[\\'anderer]

I never did anything with the van, it just sat. life issues, money issues etc forced me to wait.

I have now begun to revive the van, new tires,fixing everything that happens to a vehicle that sits for four years. i will be getting it back on the road soon.

I picked up a leaf spring conversion kit from Chris a while back, but have not installed it yet. I still like coil spring setups, but I have not made up my mind yet. I need to get it back on the road and then take another look at the suspension. One thing for sure, it cannot stay the way it is now. What do newer sportsmobiles have for a suspension setup anyway?

[Photog]

Your pair of links, seems to prevent the axle from moving straight up. It does allow either side to move up on its own.

I think this was discussed earlier in the thread, but the limitations these links place on the suspension travel, probably prevents the axle from ramming the cross member.

If you have a kit from U-Joint (Chris), then the van should sit up a bit higher, the cross member will be trimmed for clearance, and the whole suspension can move up/down smoothly.

If the leafs of the leaf springs can be set up as "parabolic" springs, they will ride almost as smooth as coils. Parabolic leaves only touch at the middle and the tips. No other contact or friction points, along each leaf. There are a couple ways to accomplish this; but the leaf pack need to come apart to do it.

[TroySmith80]

I spoke to a guy with an '88 pathfinder and it sounds like his has the same 2 problem links. He said it rides very nicely... that's pretty subjective, he was also trying to sell me the van. I just can't imagine that these would ride near as well as a design without the limitation of those 2 links.

By the way, one wheel can't even go up to absorb a bump, without the other wheel going down, or the whole van coming up (approx.) half the height of the van!

[the boogie van]

ditch the trac bars you have now and go with a traditional style single bar from the pitman arm area to about where the old passenger side rod ends. should fit fine there, i see plenty off room once you get rid of all the stuff you don't need. check u joints thread, i just saw him do the same thing for a leaf spring front.

i would replace the steering too with a real inverted T style. that looks like they just kept the original i beam linkage, which is not ideal for a solid axle.

[ntsqd]

Ford did the "Y" type steering linkage on purpose. It promotes toe-in in droop, which is a good thing as it adds stability when you need it the most.