1981 Rear suspension bushings

[Gary G.]

We are well into the restoration of our 81 BG car. The rear differential was leaking on the right side. Upon removing the differential we discovered that the side yolks were hitting the center pin for the spider gears. It had mushroomed to old shafts to the point that we spent many hours with a dremmel grinding them down to remove. We took the differential to a well know shop. Talking with the shop the first question asked was how are your bushings? Mine were very worn.
Original bushing were rubber and we can no longer find them. On page 101 of the TIMJG it states check the bushing and see if they are rubber.
My Question: We have found polyurethane kits in black. Not original. Is there a source for rubber bushings or should I just take the points hit? Looking at other bushings on the car they appear to be original and all are showing age. We are replacing all of the bushings. How many points total would a complete polyurethane kit result in?
Some times form over function is a deciding factor, however in this case making the right choices now can result in several hours of labor and many dollars saved.
Thanks in advance for your advice.
Dawn Goodyear

[Richard G.]

Re: 1981 Rear suspension bushings

Gary;
My assumption is the bushing are the Trailing-Arm-Bushings that you are interested in/
Check out this recent thread:
https://www.forums.ncrs.org/showthre...g-Arm-Bushings
Think it covers everything you will need to know about polyurethane.
Condensed story is don't even consider polyurethane.
Rick

[Joe L.]

Re: 1981 Rear suspension bushings

We are well into the restoration of our 81 BG car. The rear differential was leaking on the right side. Upon removing the differential we discovered that the side yolks were hitting the center pin for the spider gears. It had mushroomed to old shafts to the point that we spent many hours with a dremmel grinding them down to remove. We took the differential to a well know shop. Talking with the shop the first question asked was how are your bushings? Mine were very worn.
Original bushing were rubber and we can no longer find them. On page 101 of the TIMJG it states check the bushing and see if they are rubber.
My Question: We have found polyurethane kits in black. Not original. Is there a source for rubber bushings or should I just take the points hit? Looking at other bushings on the car they appear to be original and all are showing age. We are replacing all of the bushings. How many points total would a complete polyurethane kit result in?
Some times form over function is a deciding factor, however in this case making the right choices now can result in several hours of labor and many dollars saved.
Thanks in advance for your advice.
Dawn Goodyear

Dawn------

I'm assuming that you are referring to the bushings on either end of the aluminum differential crossmember. If so, the GM bushings are discontinued. However, OEM-style, rubber material replacements are easily available. This same bushing was used on many other GM vehicles of the period. The Moog part number is K6116. NAPA part number is 2674302.

I would not use polyurethane replacements under any circumstances.

If you are referring to any other bushings, advise.

Additional information: the original aforementioned bushings were GM #527595. These were discontinued in April, 1994 and replaced by GM #527593. The latter were discontinued some time ago. Some NOS examples of the 527593 might be found. However, I think the Moog or NAPA bushings will be fine and will not be discernibly different from the GM bushings.

[Gary G.]

Re: 1981 Rear suspension bushings

We are looking at the strut rod bushings. We do have a set of NOS for the cross member.
Also looking at the trailing arm bushing.
THanks Dawn

[Joe L.]

Re: 1981 Rear suspension bushings

We are looking at the strut rod bushings. We do have a set of NOS for the cross member.
Also looking at the trailing arm bushing.
THanks Dawn

Dawn------


Strut rod bushings are still available from GM under GM #3829519. Also available from Corvette vendors like Dr. Rebuild and aftermarket sources.

Trailing arm forward bushings are also still available from GM under GM #3743857. Also, available as above.

The trailing arm bushing retainers and plates are GM-discontinued. In most cases the plates can be re-used. The retainers can be obtained as described above.