IRS upper control arm bushings

TWM

Registered User
...have the IRS out of my car and disassembled. I noticed that the upper control arms appear to be interchangeable side-to-side, but the inner end bushings are not centered in the control arm. Is one in backwards or is the inner pivot on the cradle offset on one side to compensate for the bushing alignment. Or, are there two different part numbers for the left and right side????

Thanks for your thoughts on this.

TWM
 
Left and right upper rear control arms are the same. The bushings have an eccentric in them, for extra camber adjustment. I don't think all of the 89 - 91 cars had the eccentrics originally installed.


cheers,
Ed N.
 
Same thing

I had mine apart a month or two ago. I had the same experience and if I remember right the frame end of the arm is not centered on the knuckle end. It was my impression that this bushing not only adjusts camber through the eccentric center piece but also keeps the upper arm perpendicular to the hub through the reverse installation of the inner bushing from side to side. Moral of the story, yes the arms are the same, the bushings are the same but the bushing goes in differently from side to side.
If you decide to change these out, they are a bit pricey (I paid ~$45 each) and can be tough to get out. I dismantled each using a chevy wrench (big hammer) and some sockets until I was down to the inner sleeve. Then I put a hacksaw blade through the shell and put the hacksaw frame on afterwards. After a little cutting (being careful not to cut into the arm) I was able to collapse the shell enough to get it out. The new one slid in with just a little convincing...Good luck...my wheel hop is significantly less now that I replaced the knuckle and upper arm to frame bushings...

Anthony
 
fast Ed N said:
Left and right upper rear control arms are the same. The bushings have an eccentric in them, for extra camber adjustment. I don't think all of the 89 - 91 cars had the eccentrics originally installed.


cheers,
Ed N.
Ed,
Thanks for the info. Now the question is this: Since the bushing isn't centered in the control arm (front-to-back, not the mounting hole eccentric) it would seem that one side would have 'caster' since the inner pivot on one side would be further back than the other side.

...sorry for all the questions, but I'm going to make up a set of tube/rod end upper control arms and I can't quite reconcile the front-to-back location of the inner pivot.

:confused:
TWM
 
Coast to Coast SC said:
I had mine apart a month or two ago. I had the same experience and if I remember right the frame end of the arm is not centered on the knuckle end. It was my impression that this bushing not only adjusts camber through the eccentric center piece but also keeps the upper arm perpendicular to the hub through the reverse installation of the inner bushing from side to side. Moral of the story, yes the arms are the same, the bushings are the same but the bushing goes in differently from side to side.
If you decide to change these out, they are a bit pricey (I paid ~$45 each) and can be tough to get out. I dismantled each using a chevy wrench (big hammer) and some sockets until I was down to the inner sleeve. Then I put a hacksaw blade through the shell and put the hacksaw frame on afterwards. After a little cutting (being careful not to cut into the arm) I was able to collapse the shell enough to get it out. The new one slid in with just a little convincing...Good luck...my wheel hop is significantly less now that I replaced the knuckle and upper arm to frame bushings...

Anthony

Anthony,
Thanks for your input. ...good to hear that someone else has the same question. I'll be spending a long night in the garage with a square and tape measure.

TWM
 
Back
Top