Trailing arm help needed
Thread Starter
Burning Brakes
Joined: May 2004
Posts: 782
Likes: 27
From: Bend OR
Trailing arm help needed
Assembling the rear suspension on the '66. Rebuilt arms, new bushings, new pivot bolts, new shims.
How tight should the pivots be? I don't find a torque spec. I have them pretty snug but when I move the arm the shims (one side) move with it.
Also, is the lower edge of the pivot cavity the droop stop when the shocks are not installed? Or is it the halfshafts or camber struts? In other words, do the half shafts and or shocks and struts need to be installed before the spring? I could figure this out but it's better to avoid the mistakes I'll inevitably make otherwise.
How tight should the pivots be? I don't find a torque spec. I have them pretty snug but when I move the arm the shims (one side) move with it.
Also, is the lower edge of the pivot cavity the droop stop when the shocks are not installed? Or is it the halfshafts or camber struts? In other words, do the half shafts and or shocks and struts need to be installed before the spring? I could figure this out but it's better to avoid the mistakes I'll inevitably make otherwise.
Thread Starter
Burning Brakes
Joined: May 2004
Posts: 782
Likes: 27
From: Bend OR
Rubber bushings.
Scott, I find no reference anywhere to cotter pins securing the shims(I have the original shop manuals in addition to all the other usual books). There is no place to do that. I also have pictures of some cars in process and I just see the (long replacement style) shims sticking out of the frame and touching the bottom edge. The assembly instructions don't show this either.
Scott, I find no reference anywhere to cotter pins securing the shims(I have the original shop manuals in addition to all the other usual books). There is no place to do that. I also have pictures of some cars in process and I just see the (long replacement style) shims sticking out of the frame and touching the bottom edge. The assembly instructions don't show this either.
Last edited by IGO200; Nov 18, 2007 at 12:37 PM. Reason: added info
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,918
From: Washington Michigan
The long cotter pin to retain the "slotted" shims didn't enter production until 1971, but it's a great retrofit; photo below shows it on Paul67's car - cotter pin is directly below and slightly rearward of the pivot bolt. 
Thread Starter
Burning Brakes
Joined: May 2004
Posts: 782
Likes: 27
From: Bend OR
Thanks John! I like that. It makes a lot of sense. I'll do that on mine today. Oh, there goes some more of those NCRS points! Everytime I make my care "better" It's worth LESS!
Oh, so can I install the spring with the arms at full droop resting on the bottom of the frame slot, without having the halfshafts in place?
Oh, so can I install the spring with the arms at full droop resting on the bottom of the frame slot, without having the halfshafts in place?
Last edited by IGO200; Nov 18, 2007 at 02:29 PM. Reason: addition
Thread Starter
Burning Brakes
Joined: May 2004
Posts: 782
Likes: 27
From: Bend OR
Still not comfortable that everything is right on this. I have shimmed the arm with a hard push fit in the shims, torqued to 40 pounds. I did not want to go to 50- it just didn't feel solid enough. The shims on one side still move up when I lift the arm.
I did l lube the bushing bolt with anti seize. Could this be the problem?
I did l lube the bushing bolt with anti seize. Could this be the problem?
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Drifting
Joined: Sep 2007
Posts: 1,369
Likes: 0
From: Detroit MI
Still not comfortable that everything is right on this. I have shimmed the arm with a hard push fit in the shims, torqued to 40 pounds. I did not want to go to 50- it just didn't feel solid enough. The shims on one side still move up when I lift the arm.
I did l lube the bushing bolt with anti seize. Could this be the problem?
I did l lube the bushing bolt with anti seize. Could this be the problem?
As for the trailing arm pivot bolt, you should try to use the same amount of shims in each of the 4 places or at the very least, the same number in the smae places. i.e., outer slots versus inner slots. I try to put the very skinny shims in between the thicker shims so i can pound them in tight. Then i tighten the bolt down and because i pounded the shims in, i know everything is sandwiched in very tight so i can tighten the bolt to 50 lbs or so.
I can't remember when the cotter pins came in to play, but its definately a good idea. Just drill a small hole in the frame in front of the reinforcement "steel strap" that wraps around the outer edges of the T arm hole just as JohnZ said.
