Hey everyone,

On the '71 I recently bought, the seat angle is a bit too far back for my likings (either that or something is worn and so I'm sitting too low, but either way...).

So I read in the owners manual to adjust it with shims... but these shims are long gone and there's no actual instructions for me to use to create new shims. Also I pulled the seat foward and noticed the rubber bumpers are broken and probably not actually softening any of the load.

So, two questions...

1. Looking at mid america motorworks:

http://www.mamotorworks.com/corvette?frame=4.9644

On a '71 I should have these bumpers screwed in to the floor:

http://www.mamotorworks.com/lightbox...&title=602-235

And these ones screwed in to the seat back itself:
http://www.mamotorworks.com/lightbox...&title=602-233

However, looking at how it's set up at the moment, it looks to be set up somewhat like a '69, so it has these bumpers screwed in to the floor (which are broken):
http://www.mamotorworks.com/lightbox...&title=602-237

And these screwed in to the seat back:
http://www.mamotorworks.com/lightbox...&title=602-235

Soooo, what should I buy and where should I put it? Will the recommended '71 style bumpers and stops work with my seat? Or should I get the '69 style ones?

Second question:
2. How exactly do you shim them up to adjust the seat angle?

I see these shims:

http://www.mamotorworks.com/lightbox...&title=634-045

Do I unbolt the seat back release strap and insert one or both of those shims? Once that shim is in, do I also need to shim under the seat back bumpers to stop load going through the strap? (so put washers under these things: http://www.mamotorworks.com/lightbox...&title=602-233 )

Cheers!
Daniel

 

buy the parts for a 71 and use them as needed

 

Thanks, so the '71 seat is the same as the '69 seat, they just changed the arrangement of the bumpers?

I found this which answers my question on the shims too.

http://forums.corvetteforum.com/c3-g...ls-please.html

 

well one thing can lead to another. may need some new seat foam too. and dont forget the seat covers. and then you mys as wheel go for the new carpet and door panels. enjoy.

 

No, the 69 seats are different... The hardware, bumpers and locks are not the same and the seat is a lower profile seat.

Can you post a picture of the seat?

The two bumpers in the back should allow you to make just about any change needed to be comfortible without shimming.



If there is damage to the seat bottom where the lower bumpers screw in, this will fix it in most cases.

 

After googling pictures of '69 seats, mine appear to be the '71 style. Here's mine:



This is what's currently mounted in the seat bottom/floor, the rubber is broken on it:



While this is mounted in the bottom of the seat back:



So should they be mounted the other way around, with the rubber bumper mount being in the seat back rather than in the seat base and the steel ones mounted in the seat base instead?

 

the rubber is missing from the steel piece in the seat back

 

They have the bumpers backwards.... lol The bumpers I posted in my picture above are the upper bumpers.

Take the uppers out of the bottom... swap them and note how long the threaded portion is... It should be something like 2.5" long. Put them in the seat back and then put the bumpers in the back in the bottom and then adjust the back to your desired position. If the threaded screw on the upper bumpers isn't long enough measure them and post here. I'll measure a new one tomorrow.

Willcox

 

Cool! Will swap them around tomorrow and see how it fits. Thanks for the advice, Willcox!

 

My pleasure.... hope it fixes your problem.

 

I need to do this on my 74 as well. I looked at the shim kit on the Willcox site. I assume the regular washers are for the rubber bumpers. I know the rectangular shims go under the seatback latch mechanism. Do you order one set per seat?

John

 

One per car.

 

There must be some rule that nothing on a Corvette can ever be simple, even if it's just pulling out a few bolts and putting them back in again

Whoever put the bumper/stop screw in to seat back destroyed the thread on one of them when they did it. I went to remove it and the screw head was already too damaged to use and I could see there were already scuff marks from someone having to use a plumbers wrench to get it in.

To get it out I had to use multigrips and slowly work it out quarter turn by quarter turn

Of course, this means I can't get the correct rubber bumper in to the hole now until I can get my hands on a tap in order to re-cut the threads.

Anyone know what size bolt and thread pitch the rubber bumpers are?

 

I don't remember, but tomorrow I'll measure them for you if someone doesn't post before hand.

 

I took the bolt to work and asked one of the guys in the machine shop and he measured it, in case anyone else runs in to a similar problem, he said it was 5/16" - 18.

Unfortunately the one tap set he was missing was 5/16", doh! Looks like I'll have to buy one, or maybe ask my local mechanic if he has one he can run through the hole for me.

Cheers,
Tudz

 

You are correct. 5/16 - 18

 

I had the same problem when I bought my 71 only my seat was too upright. On the bottom of the seat there are (2) large Phillips screws. The so-called shims are just washers. I removed mine (there were about (8) on each side) & got the seat in the position I wanted it. If the rubber bumpers are damaged that is a different story. You will have to buy those specifically for you Vette.

 

Be aware that often the weld for these break on the seat bottoms and the steel frame can also bed slightly on the seat backs. Have straightened and rewelded many of them.

Also have made spacers from Delrin (plastic) instead of using a bunch of washers.