PST POLYGRAPHITE BUSHINGS ASSISTANCE NEEDED

billkrz

Veteran Member
Apr 25, 2015
128
Waynesboro, Va
Has anyone used the PST Polygraphite Body Mount Bushings on their second gen Camaro? My body shop recommended these and installed them during the restoration of my '73. Now, when I drive the car and hit bumps or go up a driveway, it occasionally feels like something is moving under my driver's floor area. Could it be these bushings?
Thank you in advance for any suggestions!

Bill
 

cadillac_al

Veteran Member
Apr 22, 2015
1,100
Maine
My first thought is the subframe bushings may be loose. But, my subframe on my 78 Seville loosens up every couple years and I have to re-tighten it. I don't get a sensation of moving, it just feels a little rattley on rougher roads. I don't quite dare to use thread locker because I may want to change those bushings someday. I don't know what else could cause a moving sensation under the drivers floor.
 

CorkyE

Veteran Member
Lifetime Gold Member
Nov 4, 2004
11,781
Ringgold, GA
Definitely crawl under there and take a look, see if the bushings are squished or distorted. I'm not a fan of polygraphite for that reason. Also check the condition of the A arm bushings and put a wrench on your suspension bolts/nuts.
 

billkrz

Veteran Member
Apr 25, 2015
128
Waynesboro, Va
Thanks for the suggestions fellas! Sounds like it is not the PST polygraphite bushings but the tightening of them. I think the torque is 75-80 pounds, correct?
 

Lowend

Administrator. .a car, a man, a maraca.
Staff member
Lifetime Gold Member
Mar 25, 1999
16,809
San Jose, CA, USA
I ran the PST's for subframe bushings... they work fine as they are in a non-rotational application. BUT - I would be wary if the shop broke lose one of the captured nuts when they installed them.
Subframe bushings are a miserable job to do, and you absolutely have to use some sort multi hour soak of penetrating prelube before the old bolts. Folks who don't know with just black em with an impact gun and sheer off the spot weld holding in the factory nut.
 

billkrz

Veteran Member
Apr 25, 2015
128
Waynesboro, Va
Thanks for your input. I guess if I put my torque wrench on them, I should be able to tell if the captive nut is loose pretty easily, right?
 

8pack

Veteran Member
Lifetime Gold Member
Aug 29, 2007
3,047
Western, MA
I have those bushings on my car for the last 20 years and they still look new. They are pretty solid, way harder than rubber. I have not issues like you described, as others have said check to see that they are tight as well as anything else attached to the frame under there...

Are your rear differential Ubolts and front and rear spring shackles tight (but not too tight with the shackles or they will bind)? A loose rear end might give you that same feeling.
 




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