1967 Rear Suspension/Alignment Question

[Carl R.]

Hi Yall!

I recently replaced the passenger side rear trailing arm on my 1967 car with a rebuilt assembly. When inserting the trailing arm into the frame "window", I was able to replace all of the rectangular shims except a 1/8" shim. I considered this was probably due to a previously worn bushing being "thinner" than the new bushing. All of the shim pack was located lateral (outboard) of the trailing arm itself.

Now after driving the car around the block I noticed the steering wheel is no longer "centered"; tracking is good but not perfect as before. Obviously the car needs re-aligned. My questions are:

1. Should I try to reinsert the 1/8" shim I could not replace before (by somehow prying medially on the trailing arm)? Can this be done without diassembling hte suspension? Isn't the trailing arm pivot bolt under great stress with the spring loading it?

(the service manual is rather vague on this point - how did the factory do it?)

2. Do alignment shops usually add/subtract these shims when aligning? (I have seen/heard horror stories about "creatively bent" strut rods)

Thanks yall!

Carl

[Joe L.]

Re: 1967 Rear Suspension/Alignment Question

Carl----

Wear or deterioration of the trailing arm bushings will not affect the overall "thickness" of the trailing arm bushings measured from the washer-like retainer on one side to the washer-like retainer on the other side. I suspect that your replacement trailing arm or the bushings installed in it were dimensionally different than your originals. Or, the bushings were installed incorrectly.

I would not attempt to "pry" apart the the frame area in which the forward edge of the trailing arm resides. Sometimes, however, it is necessary to use some force to insert the shims so that you have a tight shim pack on both sides of the bushing, which is essential. Although I can understand that the shim packs might be a little different after installation of a replacement trailing arm, I am surprised that you have a 1/8" shim "left over".

I have never seen a circumstance in which the shim pack for a particular trailing arm needed to be entirely on one side of the forward bushing; something seems way out of whack here. Also, the trailing arm pivot bolt(which goes through the bushings) is under no particular loading with the rear spring installed. Alignments are commonly performed, with shims added, removed, and repositioned, with the spring and all other suspension components installed in the car. All that needs to be done to do this is loosening of the pivot bolt castle nut located on the outboard side of the frame.

Finally, the rear trailing arm alignment shims control rear wheel TOE IN/OUT only. The strut rods, and their adjustment cams, control rear wheel CAMBER. The strut rods are sometimes bent by incompetents to adjust camber.

[Joe L.]

Re: 1967 Rear Suspension/Alignment Question

Carl----

Wear or deterioration of the trailing arm bushings will not affect the overall "thickness" of the trailing arm bushings measured from the washer-like retainer on one side to the washer-like retainer on the other side. I suspect that your replacement trailing arm or the bushings installed in it were dimensionally different than your originals. Or, the bushings were installed incorrectly.

I would not attempt to "pry" apart the the frame area in which the forward edge of the trailing arm resides. Sometimes, however, it is necessary to use some force to insert the shims so that you have a tight shim pack on both sides of the bushing, which is essential. Although I can understand that the shim packs might be a little different after installation of a replacement trailing arm, I am surprised that you have a 1/8" shim "left over".

I have never seen a circumstance in which the shim pack for a particular trailing arm needed to be entirely on one side of the forward bushing; something seems way out of whack here. Also, the trailing arm pivot bolt(which goes through the bushings) is under no particular loading with the rear spring installed. Alignments are commonly performed, with shims added, removed, and repositioned, with the spring and all other suspension components installed in the car. All that needs to be done to do this is loosening of the pivot bolt castle nut located on the outboard side of the frame.

Finally, the rear trailing arm alignment shims control rear wheel TOE IN/OUT only. The strut rods, and their adjustment cams, control rear wheel CAMBER. The strut rods are sometimes bent by incompetents to adjust camber.

[Carl R.]

Re: 1967 Rear Suspension/Alignment Question

Ahhh..something would be amiss here...all is not well in Mudville....

I debated trying to re-install the shim myself but decided that would be pointless and masochistic since realignment is required anyway. Now I have to find a shop to entrust with the little yellow car...

Thanks for your help Mr. Lucia!

Carl

[Carl R.]

Re: 1967 Rear Suspension/Alignment Question

Ahhh..something would be amiss here...all is not well in Mudville....

I debated trying to re-install the shim myself but decided that would be pointless and masochistic since realignment is required anyway. Now I have to find a shop to entrust with the little yellow car...

Thanks for your help Mr. Lucia!

Carl