Denso starter contact replacement.

MoGas

Central Scrutinizer
Since many of the vehicles on this forum are foreign, I figured I’d do a little tech write up on replacing the starter contacts in a Denso gear reduction starter.

How this came about:

My wife’s 1999 Grand Caravan 3.3l V6 Flex Fuel minivan has been having a starter “click” but no engagement of the starter drive motor. Having had the same problem in my Cruiser some months ago, I thought I’d look at the starter. Low and behold, it is a Denso gear reduction type. I called my local Dodge dealer to see about getting a plunger and contacts and I was told “The starter is not a serviceable part, it just gets replaced”. I was not to be deterred.

I went online and found the plunger kit at Checker Auto, in stock, for ~13 bucks. On the CSK auto parts site there is a link to see what the part you are inquiring fits. It is the same kit that I now keep as a trail spare for my 80. I bought the kit, and proceeded to remove the starter. Here is the progression of the repair, including digital images that should be basically the same for any Denso gear reduction starter.

I am not including images of the removal/install as that will vary with the vehicle.

This is the starter on the bench:


The Denso tag:


Place the starter securely in a vise using soft jaws. I have aluminum jaw covers, you may need to use wood pieces.


Remove the 3-7mm screws that secure the solenoid cover to the housing. This will expose the plunger. There will be slight spring tension on the cover, but it is not much and should be very easy to overcome by hand pressure on the cover:


Pull the plunger out of the solenoid housing and set aside. You will now see the contacts on either side of the housing:
Side note: Notice that the contacts are worn down and pitted. The major failure can and has been that the contacts get worn to the point that when the starter engages, the plunger will stick between the channels dug out of the contacts keeping the starter engaged, even if you remove the key from the ignition!! There is full battery amperage going through the motor and if this happens you run a great risk of your vehicle catching fire. That is why it is important to address this issue as soon as you start to get the starter "click".


Remove the spring from the housing and set to the side. You will be reusing this part!! Notice the ball in the bottom of the hole. On my cruiser, the ball could be removed and potentially lost by turning the starter over from the position illustrated. On this particular version, the ball is retained by a ridge at the top of the hole and can't come out unless you take the starter solenoid screws out of the other end of the solenoid housing.


Remove the nut that holds the wire that transfers power to the starter drive motor:


Remove the power transfer wire from the contact stud:


Remove the 14mm nut that holds the contact stud in position:
 
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MoGas

Central Scrutinizer
Remove the stud and contact from the solenoid housing:There may be extra pieces that come out at this time, depending on application. Mine were; Contact, Stud, Insulator, Paper gasket, and O-ring.



Remove the 14mm nut from the other side contact stud and remove the stud. On my application, the stud pushes freely towards the center of the solenoid housing and there is an O-ring on the outside of the stud:


Remove the other contact. On my application, the contact was slightly stuck and required persuasion from a screwdriver. Do not bend the little piece of metal that the contact is sandwiched between. You will need to rotate the contact along the axis of the stud to remove the contact without disturbing the thin metal.


You should now have parts that look similar to these in this order:
 
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MoGas

Central Scrutinizer
Reassembly

This is the kit that I purchased:Yours may differ.


The kit contained a new plunger and 4 different contacts. You need to match the parts to your old parts:




The stud on the side that connects to the battery is knurled and needed tapped together:



Your stud for the battery side should look similar to this:


Insert the contact, stud and other pieces into the solenoid housing and place the washer and nut on the stud finger tight:
 
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MoGas

Central Scrutinizer
Insert the new contact for the load side and then insert the stud, o-ring then the washer and nut finger tight:




To keep the contacts flat while tightening, My Toyota Manual instructs you to use a press to put approximately 200lbs. of force on the contacts to torque the nuts. I machined a little piece of steel to fit in the place of the plunger for this step. In the bush you could easily press a socket down by hand and have a partner tighten the stud nuts:




I used the Toyota torque spec of 12 lb/ft on mine:


My smallest ft/lb torque wrench only goes down th 15 lb/ft, so I used my lb/in torque wrench, set to 144 lb/in:
 
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MoGas

Central Scrutinizer
After torquing the stud nuts, install the spring:


Install the new plunger:


Actuate the plunger a few times by pushing it down to make sure there is no binding:


Install the solenoid cover gasket and cover. I used the Toyota torque spec of 22 lb/in for the 3-7mm cover bolts:


Place the starter drive motor wire to the stud and tighten. I used the Toyota torque recommendation of 10 lb/ft:



And that's all.

Now you saved yourself possibly hundreds of dollars of replacing the entire starter assembly or thousands in a vehicle lost to fire or worse, loss or injury of persons.


This is a very easy task that if you can remove your own starter, you can complete.


Good luck and happy motoring,
Dave:safari-rig:
 
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madizell

Explorer
You mentioned verifying that the plunger does not bind. Any tips for remedying a sticking plunger, and is there any lubricant used or needed in the plunger barrel? Looks like a spot where dust and debris could collect to prevent the plunger from bottoming on the contacts, or worse, sticking in the down position. Grease would probably just make the situation worse by collecting and holding dirt, but perhaps a dry graphite would be of use?
 
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DaveInDenver

Luddite
This is repair is very common on Toyota trucks. FWIW, Roger Brown (a Toyota mini truck guru) has another write-up and a second source for the contacts ($5/each plus $1 for postage, so the pair is $12). He can make them for any Denso starter, Chrysler, Dodge, Mitsubishi included.

http://4crawler.com/4x4/CheapTricks/Starter.shtml

As far as lube, I used plain dielectric grease on mine, but I doubt that is an ideal material. It's held up OK so far, but I have not removed it to clean and check it in a while.
 

MoGas

Central Scrutinizer
madizell said:
You mentioned verifying that the plunger does not bind. Any tips for remedying a sticking plunger, and is there any lubricant used or needed in the plunger barrel? Looks like a spot where dust and debris could collect to prevent the plunger from bottoming on the contacts, or worse, sticking in the down position. Grease would probably just make the situation worse by collecting and holding grease, but perhaps a dry graphite would be of use?
I've only done this on a handful of Denso starters and I've not had one that binds. I just do that out of habit. I used to rebuild hydraulic, pneumatic components and electro servos for aircraft and you always check for binding.

I use no lube. There is always a little factory lube on the spring, I just leave it.
 

Sloan

Explorer
So I went to start my FJ60 the other day and all I got was a click, click sound. I took a second, cussed some and then it started right up like usual. Is this an indication that I need a new starter or that this rebuild might be in order?
 

MoGas

Central Scrutinizer
Sloan said:
So I went to start my FJ60 the other day and all I got was a click, click sound. I took a second, cussed some and then it started right up like usual. Is this an indication that I need a new starter or that this rebuild might be in order?
I would say that the contacts are probably ready to go. Here is the kit I believe yours would take or you could get the parts separately through Toyota. Either way, it's much less expensive than replacing the whole unit.

Dave
 

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