C3 Rear Spring Rubber Donuts
Thread Starter
Racer
Joined: Dec 2005
Posts: 368
Likes: 4
From: . New Zealand
C3 Rear Spring Rubber Donuts
Six weeks ago I replaced the rubber donuts on the spring hanger bolts, on our '76. At the time I thought it strange that there was no cup under the spring leaf to receive the rubber donut top flat flange. The spring has a 1" hole, but nothing else. There is a large heavy curved washer under the lower curved rubber donut face, but the 1" hole in the spring looks way too big to receive the rubber donut shank.
What's happened is the donuts have split radially and the hanger bolt is in danger of squishing the rubber out and going steel/steel. Have my springs lost these cups?
In any case, I'm going to machine some because I think its better if the rubber donut is contained better against the spring.
What's happened is the donuts have split radially and the hanger bolt is in danger of squishing the rubber out and going steel/steel. Have my springs lost these cups?
In any case, I'm going to machine some because I think its better if the rubber donut is contained better against the spring.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
The curved washer/cup goes on the spring first (mine shown in black), then the cushion, then the flat washer and nut.
Here you can see the flange that is pushed into the hole in the spring.
Here you can see the flange that is pushed into the hole in the spring.
Last edited by Paul L; May 24, 2009 at 08:52 AM.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Six weeks ago I replaced the rubber donuts on the spring hanger bolts, on our '76. At the time I thought it strange that there was no cup under the spring leaf to receive the rubber donut top flat flange. The spring has a 1" hole, but nothing else. There is a large heavy curved washer under the lower curved rubber donut face, but the 1" hole in the spring looks way too big to receive the rubber donut shank.
What's happened is the donuts have split radially and the hanger bolt is in danger of squishing the rubber out and going steel/steel. Have my springs lost these cups?
In any case, I'm going to machine some because I think its better if the rubber donut is contained better against the spring.
What's happened is the donuts have split radially and the hanger bolt is in danger of squishing the rubber out and going steel/steel. Have my springs lost these cups?
In any case, I'm going to machine some because I think its better if the rubber donut is contained better against the spring.
cc
Last edited by CCrane65; May 24, 2009 at 09:40 PM.
Team Owner
Joined: Sep 2006
Posts: 31,237
Likes: 4,330
From: Westminster Maryland
Hi T,
There have been more than a few comments recently about the quality of the rubber bushings and the fact that they split as you described with very little use.
You may want to try some from a different source or perhaps someone can make a suggestion of a vendor's bushings they've had good luck with.
Regards,
Alan
There have been more than a few comments recently about the quality of the rubber bushings and the fact that they split as you described with very little use.
You may want to try some from a different source or perhaps someone can make a suggestion of a vendor's bushings they've had good luck with.
Regards,
Alan
Instructor
Joined: Jan 2008
Posts: 143
Likes: 1
From: Beaumont TX
Alan 71:
Dittos. On another current thread regarding bushings I am asking if folks have found the huge price difference between GM bushings and others to be worth it.
Can anyone offer some personal experience here?
Dittos. On another current thread regarding bushings I am asking if folks have found the huge price difference between GM bushings and others to be worth it.
Can anyone offer some personal experience here?
Burning Brakes
Joined: Oct 2006
Posts: 1,006
Likes: 28
From: Lutz Florida
I replaced mine with urethane cushions. Two of them just crumbled and fell apart and the other two had cracks in them. This was in less than 500 miles.
I replaced them with rubber cushions and a year later the rubber ones still look like new. I bought them from a local Corvette shop and parts supplier. They were loose and not in a bag so I doubt they were OEM parts but they are working just fine. I think I paid something like $2.50 for each cushion - they were pretty cheap.
I replaced them with rubber cushions and a year later the rubber ones still look like new. I bought them from a local Corvette shop and parts supplier. They were loose and not in a bag so I doubt they were OEM parts but they are working just fine. I think I paid something like $2.50 for each cushion - they were pretty cheap.
Burning Brakes
Joined: Sep 2005
Posts: 1,050
Likes: 205
From: Lewes Delaware
I have to replace the original ones in my 73. Questions:
1) how difficult a job is this to do?
2) what equipment is required to do it yourself"
3) where did you get the parts and can you post a list of what you got?
1) how difficult a job is this to do?
2) what equipment is required to do it yourself"
3) where did you get the parts and can you post a list of what you got?
Burning Brakes
Joined: Oct 2006
Posts: 1,006
Likes: 28
From: Lutz Florida
1. This is one of the easiest jobs to do; maybe 10 - 15 minutes per side.
2. You need a good jack, large "C" clamp (4"), a block of wood, wrenches, and pliers to pull out the cotter pins. Spray some PB Blaster on the nuts and bolts a day or so before to loosen them up.
3. If the bolts and hardware are still good you can reuse them and just buy the spring cushions. You will need four. If not you can get a kit with new bolts washers and cushions. They are available from a number of supporting vendors on this site. I'm pretty sure that both Wilcox and Vette Brakes carry them.
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Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
New, bring installed (first set):
After 1 month(2nd set, changed rear bolts on 2nd replacement):
Polys
It's pretty easy, but can be dangerous, if not done right. Stock76 covers the tools pretty well, use the C-clamp to clamp the jack to the spring for safety. I jack-stand the rear end, then put a spare tire under the side i'm working on in front, for safety. I then put jack, piece of 2x4, and clamp the jack to the spring, just inside the wheel, first flat of the lowest leaf. Put the jack in line (accross car) with the spring, so it can 'walk/roll' with the spring, as it's lifted. jack it up till I just see the pressure just come off the lower bolt bushing, then R&R them. easy really.
Last edited by RunningMan373; May 24, 2009 at 10:21 PM. Reason: details.....
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
The cushions I put on a couple of weeks ago are rubber. I bought them at Carlisle ~8 years ago when I had a 1979 but....they became a round-to-it. That is pretty much the pre-Chinese era so they should be OK but I'll keep an eye on them.
These are the ones I took off my 1974. Pretty sad.
These are the ones I took off my 1974. Pretty sad.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Premium Supporting Vendor
Joined: May 2000
Posts: 4,312
Likes: 70
From: Clearwater FL
You will most likely have to tap the flat plate in place with a hammer and tweak it with a screwdriver to get it lined up.
Burning Brakes
Joined: May 2006
Posts: 893
Likes: 7
From: Hazerswoude-Rijndijk Zuid Holland
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS