how to fix brake/bump steer in 88 suburban that had 2.5 inch lift springs installed

[Rockhounder]

Any help would be most appreciated of a bump/ nose dive/braking steering issue

Before we installed 2.5 inch springs on the front of my 88 suburban 1500 with solid axle, there was no problem. After we installed the springs, it seemed like the lift was more like 3 inches, but close to 2.5 First thing I noticed was that my steering wheel now did not sit level and even, but turned about 40 degrees to one side. We adjusted the turnbuckle on the connector rod that is between the steering box arm and the axle arm to make the steering wheel level.

Now, when I have mild braking, I do not notice anything, but if I do a sudden hard braking, while holding onto the steering wheel, the suburban violently turns to the right. If I do hard braking and do not touch the steering wheel, the vehicle remains pretty much straight and good, but the steering wheel itself spins.

I know this must be some straightforward issue, so far every offroad shop I have talked to says that nobody does anything special to the steering gear or linkage for anything under a 4 inch lift.

Obviously there is an issue, should I have not adjusted the turnbuckle, instead taking off the steering wheel and rotating level and putting back on the steering shaft spline?

Any solutions or have any of you dealt with this before?

Any help is most appreciated
Paul

 

[bob91yj]

Does your front suspension have a track bar (Panhard bar)?

A good pic from head on of your front suspension/steer linkage would help diagnose the issue as well.

 

[155mm]

Did you get it aligned after the installing the springs?

 

[Rockhounder]

Does your front suspension have a track bar (Panhard bar)?

A good pic from head on of your front suspension/steer linkage would help diagnose the issue as well.

I will take a picture and post tomorrow. Just from memory, the axle is bolted to the springs via u bolts. There are four shocks going tothe front axle, two on each side from frame down to an protruding shaft they mount to and secured by one nut over both. there is a torison bar, which is attached to a cross member right behind the front bumper, under the radiator assembly. The torison bar attaches to the right side of each shackle(and spring stack) assembly which locks the axle to the springs. The springs are solid mounted on the fore end, they hang on 3-4 inch long shackles to the rear frame mounts. The left wheel housing casting has a curved, beef rib shaped metal bar coming out of it, which has two attachment points, first goes to a long bar/rod which goes across to the passenger side axle casting for tying both wheels to the steering(this also has mounted to it a steering damper shock absorber)

. the second attachment from the drivers side rib attaches to about a one foot long rod, which has a turnbuckle threading assembly in the middle for adjusting left/right steering wheel orientation. this bar goes to a short, perhaps 7-8 inch long arm which is attached to the rotating shaft coming out the bottom of the steering reduction gear box.

The axle goes out (on both driver and passenger sides) to a hinged outer hub, which uses a universal joint to transfer power. this ends up in an integral brake disc/bearing hub, which also houses the autolocker assembly. THe brake caliper is mounted to the outer rotating hub part of the axle. The axle has under the passenger side, the differential which has the driveshaft going out back.

To my memory this is all that makes up the front axle, springs, etc assemblies, other than the brake lines.

 

[Rockhounder]

Did you get it aligned after the installing the springs?

yes they did an alignment, but they said that it was already pretty close to spec

 

[kojackJKU]

It sounds like some bushings etc worn in your front end. Or maybe the steering box. Also if the rig pulls to the right when braking, then your brake caliper is gripping on the right side more than your left. You should have your brakes serviced to make sure your caliper is not sticking and that everything is good.

Just a few things to look at first.

 

[cyclic]

No they are all WRONG, I can't believe none of those shops could take care of you. Very simple and not too expensive. It's made by Skyjacker, goes by part number CA50.
I also run a 2.5 lift, I wanted it to work great. I found one used for cheap and installed it PDQ. Steering is MUCH better and little to no bump steer. So go online and order a 2 inch drop pitman arm. Install and enjoy. Once it's in, then adjust the pitman arm to axle link to center your wheel.

http://www.summitracing.com/parts/sja-ca50

http://offroaddesign.com/catalog/steeringcorrection.htm

ETA: you want the link to be as close to matching the spring angle as possible to limit the bump steer.

 

[cyclic]

Here's two pics of mine before and after for reference.

Before:

After:

 

[cyclic]

If you don't have them yet, also make sure you get some sway bar links.
It makes the suspension more supple by eliminating suspension bind due to sway bar travel not matching the spring travel.
You can go home made, Zoneoffroad, or ORD. I went with the Zone and you can just see them in the pics above.

http://zoneoffroad.com/zone-offroad-products-suspension-sway-bar-link-chevy-gmc-blazer-jimmy-pickup-suburban/c5401

http://offroaddesign.com/catalog/swaybarkit.htm

 

[monele]

Geometry looks fine from what I can see. I'd sure start checking ball joints & tie rod ends. A little lift puts more stress on them and brings out any faults. Jack the front end up and first check axle end ball joints by putting hands at 12 & 6 o'clock and try to tilt the wheel top to bottom. If there is any play, time for new joints. Have a friend turn the wheel back and forth slowly while putting just a little pressure against a wheel/tire (I often put a foot on the tire b/c I can feel if the rod end is lose that way, just don't be under the vehicle). See if you can see or feel any play in each tie rod (or you hear any clicks). Check them one at a time and don't rush. Any rod end that has even a tiny bit of play should be replaced. (and a couple of them look well used)

Also check to see that the U-bolts are properly torqued (and re-check after 50 miles, and 100 miles) if the axle is slipping even the tiniest bit in the mounts, you'll feel it. Check the spring mount bolt torque as well. I can't see if you reused the factory shackles, but if you did the bushings there could be fragged too.

I'm a little jealous of your rig. I love those old suburbans and if I didn't have 2 other project vehicles it would be tough to decide between building a 'burban or a willys wagon.

Hope you find a simple fix.

 

[4x4junkie]

No they are all WRONG, I can't believe none of those shops could take care of you. Very simple and not too expensive. It's made by Skyjacker, goes by part number CA50.
I also run a 2.5 lift, I wanted it to work great. I found one used for cheap and installed it PDQ. Steering is MUCH better and little to no bump steer. So go online and order a 2 inch drop pitman arm. Install and enjoy. Once it's in, then adjust the pitman arm to axle link to center your wheel.

http://www.summitracing.com/parts/sja-ca50

http://offroaddesign.com/catalog/steeringcorrection.htm

ETA: you want the link to be as close to matching the spring angle as possible to limit the bump steer.

×2

I would also strongly recommend you get a steering box brace with a dropped pitman arm (if you don't already have one), the dropped arm increases by a good bit the amount of force transferred from the box to the frame.

 

[Rockhounder]

Ok so here are the pics. as you can see, the angle needs to drop.

In regards to either the pittman arm, or the rib shaped attachment arm that goes on the left hub itself, I hear you guys, about the potential stresses on components. If I go with the pittman arm that is deep, it is recommended to get the steering box brace, but is there anything else needed if I go with the other end (axle riser curved attachment piece?)

 

[cyclic]

You got the idea, the issue you will run into is steering arms are so tall they will reverse your problem and the link will then run down hill. The steering arms are 4 inches, too much. The pitman arm is 2 inches, perfect for 2 to 3 inch lifts.
I plan, and you should also, on getting the bolt in steering frame brace.

 

[highdesertranger]

x2 on the drop pitman arm and the frame reinforcement. I have got to ask, that's a lot of solar up top. what for? highdesertranger

 

[Rockhounder]

x2 on the drop pitman arm and the frame reinforcement. I have got to ask, that's a lot of solar up top. what for? highdesertranger

Thanks, the solar gives me 10 amps+ going to deep cycle batteries, which powers the freezer/fridge. also gives us extra electricity to use for our keurig and electric food heater unit. Electric warming in the cab in frigid conditions is great as well. Added bonus is that the 2 inch separation between the panels and the roof keeps the interior roof noticeable cooler. With the rear batteries also connected to the front main battery, via a 2 gauge wire with isolator switch, jumping dead batteries is a lot easier, irregardless of the direction.