Originally Posted by willwren
If your subframe bushings are shot, I'd like to know why. I've never seen a bad one.
I am in the middle of this project right now. On the 93 that I recently acquired, the right rear subframe bushing has failed because the outer lip on the lower retaining washer is completely rusted away. From under the car, you can see the rubber looks a little mangled and is bulging out. The resulting symptom is a rather loud pop occurring every once in awhile when cornering / braking / accelerating hard or driving over a large bump / curb / pothole. Do not have any vibration issues.
On my 92, the subframe rusted and completely split apart in front of the right control arm. (I was expecting this to happen a lot sooner because 12 years ago the car was in an accident in which the battery exploded). Long story short, I decided to go ahead and get a new subframe for this car since it runs fine otherwise. I went to the local junk yard last weekend and found two cars where the subframes had been partially removed. At first glance, neither appeared to be rusted very badly.
When I pulled the bushings out to inspect, I found problems. The lower bushings have a metal outer sleeve which inserts into a socket on the subframe. The metal sleeve on all existing lower bushings on both subframes was completely rusted away – I mean only a pile of rust came out. The sockets on the subframe were heavily rusted too. The rear ones are deteriorated so badly that they wont hold new bushings. I am planning to weld repair the bad sockets in the frame I picked up.
The estimated $ for this project is subframe=$50, lower bushing (insulator)=6 X $6.52 ea (GMPD), local transmission shop will install frame for $150 ~ $200 (if I supply all parts), plus $ for wheel alignment.
Hoping my experience is just a fluke and not an omen for others. Both of the junk yard frames did not show any external signs of bushing problems. Even though metal sleeves were gone, the frame had not yet started to eat into the rubber real bad - however without the metal sleeve, I would think suspension might become a little more mushy. After seeing this deterioration, I am planning to do the same repairs to the 93 after I finish the 92.
Anyone else seen this?