Trailing arm install

[James H.]

Well it came out without much profanity. Now that its time to go back in, is there anything I should watch out for on the 67. Planned on putting shims back as they came out.
Jim

[Alan D.]

Re: Trailing arm install

Jim hope you measured the old bushing's thickness. Most repo's seem to be a little larger so all the original shims will not fit any longer. However if that turns out to be the case just take an equal amount off each side from the original shims.

[Wayne P.]

Re: Trailing arm install

I would replace old bolt and nut with a new one. Don't fully torque till the weight of the car is sitting back on the ground. My two cents worth. Good luck. Ps check for rust in the kick up pockets good time to repair .
I started to replace trailing arms and ended up replacing the frame.
$$$$

[Brian M.]

Re: Trailing arm install

Use slotted shims. JMHO.

[Larry M.]

Re: Trailing arm install

Use slotted shims. JMHO.

A good idea. But frame should also be drilled and the EXTRA-LONG cotter pin installed at the same time. This will help to keep the shims from coming out when car is driven.

Larry

[Jack H.]

Re: Trailing arm install

EXCELLENT advice (slotted shims) but only good IF your objective is driveability and low maintenance vs. factory/correct concours judging results...

The early cars that used double hole vs. hole + slot style shims are checked by savvy chassis judges for this level of factory authenticity.

[Gary J.]

Re: Trailing arm install

By using the slotted shims you are taking a chance of them falling out. If it were me and I had the orginal ones that would be what I would use. It will a little more aggravating installing the original one, but you would have a piece of mind that they would not be falling out.

[Larry M.]

Re: Trailing arm install

By using the slotted shims you are taking a chance of them falling out. If it were me and I had the orginal ones that would be what I would use. It will a little more aggravating installing the original one, but you would have a piece of mind that they would not be falling out.

Gary:

If you use the slotted shims AND the "long" factory installed cotter pin, they will not fall out. They are secured by the pin. The slotted shims have a secondary hole just for this purpose.

I believe GM started doing this around 1970 (+/- 1 yr).

Larry

[James H.]

Re: Trailing arm install

I'm hoping to reuse existing shims BUT can someone show a pic of how a long cotter pin holds the slotted shims from coming out.. I dont understand.
Thanks for all the information. Unfortunately I didn't measure shim thickness.

[Terry M.]

Re: Trailing arm install

Gary:

If you use the slotted shims AND the "long" factory installed cotter pin, they will not fall out. They are secured by the pin. The slotted shims have a secondary hole just for this purpose.

I believe GM started doing this around 1970 (+/- 1 yr).

Larry

One of the stranger AIM issues. The holes in the frame for the cotter pin began to appear during the 1969 model year, but the factory didn't begin to use slotted shims, with the cotter pin to hold them in, until the last week of 1970 production -- end of July 1970. Go figure.

BTW: The cotter pin passes through both sides of the frame pocket and through holes int eh slotted shims designed for just that purpose.

[Steve L.]

Re: Trailing arm install

One of the stranger AIM issues. The holes in the frame for the cotter pin began to appear during the 1969 model year, but the factory didn't begin to use slotted shims, with the cotter pin to hold them in, until the last week of 1970 production -- end of July 1970. Go figure.

They probably had 100,000 old shims in stock that they wanted to use up.

[John H.]

Re: Trailing arm install

Here's the trailing arm shim cotter pin - it's at about 5 o'clock from the end of the pivot bolt, and is 5-3/4" long.