sport power seat gears are stripped,forward and backward movement inop' anybody able to repair this gear mech. without replacing complete seat mech?

 

I'm wondering the same heh, my forward and back work, but the rest are inop

 

so far no one has found a source for replacement gears. mad sells rebuilt,so they must be getting them somewhere.

 

GM will not sell the gears OTC. I don't know why... we as mere mortals cannot get them.

 

I'm working on a repair guide for early sport seats.
If you come up with any ideas, can you let me know?
The FSM lists the gears as a replacement only item...

Link -> Sport Seat Repair Guide

 

i,m going to take the track mech. apart.Ihave a friend who owns a custom machine shop,said he can make me whatever is needed ,mabe i can have the gears mass produced for sale???

 

I would think that if you could fabricate the gears and the instructions to get to them and install, there would be a decent amount of interest. Both seats on my '96 need them. This seems to be a very common problem. Please keep us posted.

 

I would also be very interested.

 

I have seen this thread come up so many times. It could probably use a sticky. I sent an e-mail to an engineer friend with some links about the seat. He has most of the tools as he does tranny work on his Eagle Talon. I have one bad seat and one good one, and no plans for the car to be on the road until late in the spring. Now we just need to find a Saturday to figure it out.

 

What about the gearbox itself? Is that weak and allowing the gear shafts to move around which lets the gear teeth to slip past eachother?

I presume this is what happens when you hear the clicking sound at the end of motion, the case spreads out before the overcurrent switches stop the motors. And may be a reason for the slop as well.

 

It's actually the gearbox itself. Its a plastic (nylon) asm that just cracks with age. I tried doing it once, but with out the part I don't think it can be done. If I remember, its the asm that loads the gears in place, it's been a couple of years. My idea was that I would take the parts off a couple of bad ones with different problems and make one. Turns out it was this same plastic piece that just cracks in different places, and nobody sell it.

 

I would be too.

 

Hey ! I live in Australia , and I'm even interested ....
The cost of a power seat base shipped and taxes paid plus dollar conversion hurts the bank account too much to justify it.

 

Got a picture of one? wonder if it can be made on the mill.

Is that the "snap-click-bang" I get once and a while?

-- Joe

 

Here's a mechanical engineer's analysis of the assy.

The gearbox case is a 2-piece aluminum box that's riveted together - it's sturdily built and not the problem.

The gears are plastic and ultimately strip - they are part of the problem, but I don't think that they are the root of the problem.

There are plastic spacers that maintain the gears in position. These are made of a crappy plastic and have a tentency to crack. (I have had 3 gearbox assys apart and they all had the same cracked spacer pieces). Anyway when these crack, it allows the gears to shift around which leads to improper meshing of the teeth, which leads to the teeth stripping. IMHO, this is the culprit.

I have lots of gear catalogs and have yet to find an exact match - it looks like GM (or the supplier that produced these) designed a unit with custom gears. Sure, you can custom machine parts to replace the plasic, but unless you do it yourself, it's cost prohibitive.

 

I was out at Ecklers returning my original seat track core for the drivers seat. I spoke to the power seat tech about getting the gears or where I could get them. From what I understand, the company that does the re-build also fabricates the gears. Sounds like a real custom operation that has a corner on the marker. Doesn’t sound like they will be selling the gears or parts on the open market ant time soon.

I also got the drift that Ecklers does not make a killing on the sale of the seat tracks. I sure after the initial gear design and tooling are finished, the up front fabrication costs are paid for in time. Sounds like the effort is going have to come from some place else. I have been thinking of taking the passenger seat apart to get an idea of what has to be done.

Since then I have come across this post by Destoy, last post. He has done some great research on the track with pictures. http://forums.corvetteforum.com/show....php?t=1536893

This is an extract of his information. As you can see the support parts rather than the gears appear to be the problem. From my own experience so far I have seen if I hold the drive cable in a certain position everything moves correctly. This seems to support his information on what may be happening. Over the holidays I am going to disassemble my passenger seat and see what I find.
Here is his post (#23) information:

I have been working on this issue for a couple of years. Repaired some by combining parts. The tricky part is the shimming to remove the lash.

Here is an opened gearbox and track:

http://web.mac.com/dlawless/iWeb/Sit...?slideIndex=56


http://web.mac.com/dlawless/iWeb/Sit...?slideIndex=57

Notice the cracked plastic parts. It is my guess that these plastic parts crack first allowing the clearances to open. The result is partial tooth contact and the nylon gears gradually wear away.

I have found no epoxy that bonds these plastic parts. I have had marginal success in stabilizing these plastic parts by closing up the case with uncured epoxy liberally applied to the cracked areas.
END............

In regard to his post and the other information, I think I am going to try a heat weld with a similar material if mine is cracked as his were. Sounds like glue won’t work and some other creative ideas need to be engineered.

 

PcColt94: Good stuff and thanks for the pics with the arrows. I realize Christmas is upon us, but when you get the chance for follow up with any solutions, we are all ears.

 

"In regard to his post and the other information, I think I am going to try a heat weld with a similar material if mine is cracked as his were. Sounds like glue won’t work and some other creative ideas need to be engineered."

I had to take apart seven gear boxes. Please be very careful when you take the gear case halves apart. The gear shafts are shimmed. You will find small round disc (s) in each of the shaft end pockets. Do not loose their orentation. They preserve the gear train alignment. As the plastic suspension system deteriorates (cracks, etc.) the gear mesh (contact) opens and the suspension plastic cracking accelerates. Eventually the gears loose contact.

I didn't think of the heat glue. The best fix I achieved was with a plastic compatible epoxy . . . slow curing. It holds the loose plastic pieces together, i.e. it stablizes them between the metal case halves. But if you take it apart again the epoxy will shift and you are back to square one.

Sure would like to find the replacement parts . . . just the suspension plastic. I know they are out there. Reman tracks purportedly have new gear case guts . . . or do they?

 

This was a 2 day effort with no big pay off. I did not get to the point where I wanted to get to. The original problem was the rear of the seat would not move up or down.
So hears what I found.

When I disassembled the unit I found 4 broken areas. Two big ones in the main support and 2 end caps. All the gears looked OK. When the support structure breaks up, the clearances really open up and that’s the noise you hear when the teeth grind. I found no power from the gears which was the only good thing.

I spent couple of hours plastic welding the broken pieces and looked like I did a good job. But when I assembled everything back together, I had the same problem. I found if I held the drive cable up, it worked. When I ran it I heard plastic crack at the end of travel. So everything came apart again.

Checked to see if why the gears were not meshing and nothing looked wrong. But in moving the cable I could see things moving. So I welded 2 pieces that should have not been welded to stop excess movement. I re-fixed the broken part that broke again. It now dawned on me that the welded pieces were not as strong or flexible as the original plastic was. So..dont go to the stop.

I also found the swivel joints were real stiff. I de-rusted and oiled all of them real well. I think this can contribute to excess stress in the drive mechanism.

Put all back together again and it worked. But I feel it is working on borrowed time and limited to careful operation would be necessary.

The obvious key to fixing the unit is to change out the main support which is a highly professional, geared up task that most of us couldn’t even think about fabricating. The work is not rocket science, you just need the right parts. Here are some of my pictures. Good luck to all. It was fun for awhile.











*** This is my plastic welds. I used similar material to weld with.

 

Great pictures. Thanks! It looks like a Sci-Fi movie out-take.

I have a question. Obviously it's age that causes this deterioration. My 92 only has 40K miles and has always been garaged. BUT... The Driver's side will not go front to back. Right now it's all the way back and I feel like a 10 year old trying to reach the pedals. Is there a quick-fix, one-time, way to move the seat forward so that (a)I can reach the pedals and (b) Buy time to deal this this problem later?...