'67 Torque Control Arm pivot assembly

[Leif A.]

While out for a nice Saturday afternoon drive yesterday to, not only enjoy the beautiful day, but to check out the OPs of my car getting ready for the Texas Regional in Frisco, I heard what sounded like something metallic coming lose from the right rear of the car...kinda like a nut or bolt bouncing under the car as it said "bye bye". When I got to my buddies place, I put the car up on his lift to do some final detailing of the chassis and to see if I could find the missing "bolt". What I found was the right rear trailing arm (torque control arm) had shed a shim (or two). I removed the remaining four shims and bagged them. Here's my question. I had a four wheel alignment done at the beginning of summer (about 1000 miles ago). I'm thinking that obviously the pivot bolt was not torqued correctly allowing the shims to work their way lose and some to fall out. In looking at both the '67 Shop Manual and '67 Chassis Service Manual, they show a pivot bolt, washer and nut as the only pieces involved with attaching the trailing arm at the pivot point. When I look in Paragon's catalog and LIC catalog they show multiple washers and a trailing arm bushing kit (s/s). The car is going back to the alignment shop tomorrow to be fixed under my watchful eye this time...should I be looking for this bushing or just the bolt, washer and nut. Also, is it safe to drive the three miles to the shop with all the shims out? I understand that the correct shims for a '67 should NOT be the slotted kind like the shop used but, rather, the ones with holes so that they CAN'T fall out. Thanks for your advice, as always, and hope to see and meet many of you at the Texas Regional this week...the weather is going to be fabulous.

[Donald A.]

Re: '67 Torque Control Arm pivot assembly

I understand that the correct shims for a '67 should NOT be the slotted kind like the shop used but, rather, the ones with holes so that they CAN'T fall out.

The trailing arm pivot bolt/nut does not torque to a level that will fix the shims in position. The shims are held in by the hole in them that fit on the pivot bolt. If you are going to use slotted shims, they are going to fall out, unless you fix them to the frame with holes and cotter pins like in later year cars. The C2 design was not for slotted shims. Obviously a real pain for alignment work but... that's the way it is! Just my opinion

[Leif A.]

Re: '67 Torque Control Arm pivot assembly

The trailing arm pivot bolt/nut does not torque to a level that will fix the shims in position. The shims are held in by the hole in them that fit on the pivot bolt. If you are going to use slotted shims, they are going to fall out, unless you fix them to the frame with holes and cotter pins like in later year cars. The C2 design was not for slotted shims. Obviously a real pain for alignment work but... that's the way it is! Just my opinion

Thanks, Don...appreciate your quick response.

[Joe L.]

Re: '67 Torque Control Arm pivot assembly

While out for a nice Saturday afternoon drive yesterday to, not only enjoy the beautiful day, but to check out the OPs of my car getting ready for the Texas Regional in Frisco, I heard what sounded like something metallic coming lose from the right rear of the car...kinda like a nut or bolt bouncing under the car as it said "bye bye". When I got to my buddies place, I put the car up on his lift to do some final detailing of the chassis and to see if I could find the missing "bolt". What I found was the right rear trailing arm (torque control arm) had shed a shim (or two). I removed the remaining four shims and bagged them. Here's my question. I had a four wheel alignment done at the beginning of summer (about 1000 miles ago). I'm thinking that obviously the pivot bolt was not torqued correctly allowing the shims to work their way lose and some to fall out. In looking at both the '67 Shop Manual and '67 Chassis Service Manual, they show a pivot bolt, washer and nut as the only pieces involved with attaching the trailing arm at the pivot point. When I look in Paragon's catalog and LIC catalog they show multiple washers and a trailing arm bushing kit (s/s). The car is going back to the alignment shop tomorrow to be fixed under my watchful eye this time...should I be looking for this bushing or just the bolt, washer and nut. Also, is it safe to drive the three miles to the shop with all the shims out? I understand that the correct shims for a '67 should NOT be the slotted kind like the shop used but, rather, the ones with holes so that they CAN'T fall out. Thanks for your advice, as always, and hope to see and meet many of you at the Texas Regional this week...the weather is going to be fabulous.

Leif-------


If the shims have only fallen out from one side of the trailing arm forward bushing, then you don't need to take it back to the alignment shop. Simply install a shim pack in the one side that has missing shims so that you get a TIGHT pack. To do this, figure out which shims it takes to accomplish this. Then, remove the thickest shim, install the thinnest, and drive the thick shim in with a hammer. Then, install the nut, torque to spec + any additional torque needed to align the cotter pin hole.

Your car was originally fitted with the "TWO HOLE" shims, not the type that are slotted on one end. The slotted shims replaced the "two hole" for PRODUCTION about late 1969-early 1970. They also replaced the "two hole" for all 1963-69 SERVICE. I do not recommend EVER using the "two hole" shims. They make alignment difficult and, because of this, you're unlikely to get a shop to do a really good alignment. "Good enough" is the best you can expect. Plus, if you insist on the "two hole" shims, the shop might charge you by the hour for the rear alignment and it's going to take them a long time for a "good enough" job.

If the shims are installed correctly, you will have absolutely no problem with them falling out. Correctly includes:

1) Driving the last shim in with a hammer for a TIGHT shim pack:

2) Tucking the outer ends of the shim packs down into the "pocket" in the frame where they are supposed to reside;

3) Torquing the retaining bolt/nut to proper spec.

The configuration of the fasteners is shown in the AIM.

[Leif A.]

Re: '67 Torque Control Arm pivot assembly

Joe,

Thank you, as always, for a crystal clear explanation as to what needs to be done. Totally understandable as to why they went to the slotted shims. My reason for taking it back to the alignment shop was that I don't know what side of the trailing arm the shims fell out of...I pulled out the remaining ones from the right hand side of the arm so as not to lose them. Am I correct that the missing shims could have fallen out of the other side and should, therefore, have it checked?? If not, I can simply order a shim pack from one of the vendors and accomplish what you have instructed on my own. What style lock washer is used? AIM just calls for a lock washer but doesn't state what style. What about driving the car before the shims are replaced?? The Texas Regional is this week.

Regards,
Leif

[Joe L.]

Re: '67 Torque Control Arm pivot assembly

Joe,

Thank you, as always, for a crystal clear explanation as to what needs to be done. Totally understandable as to why they went to the slotted shims. My reason for taking it back to the alignment shop was that I don't know what side of the trailing arm the shims fell out of...I pulled out the remaining ones from the right hand side of the arm so as not to lose them. Am I correct that the missing shims could have fallen out of the other side and should, therefore, have it checked?? If not, I can simply order a shim pack from one of the vendors and accomplish what you have instructed on my own. What style lock washer is used? AIM just calls for a lock washer but doesn't state what style. What about driving the car before the shims are replaced?? The Texas Regional is this week.

Regards,
Leif

Leif------


If you think that shims may have fallen out from BOTH sides of the bushing, then you need to have a shop re-align it. However, if you know that the shims only fell out from one side, then the shim pack you need on the other side of the bushing is "automatic"------it's whatever it takes to completely and tightly fill the gap.

Lockwasher is a standard split lockwasher.

[Leif A.]

Re: '67 Torque Control Arm pivot assembly

Leif------


If you think that shims may have fallen out from BOTH sides of the bushing, then you need to have a shop re-align it. However, if you know that the shims only fell out from one side, then the shim pack you need on the other side of the bushing is "automatic"------it's whatever it takes to completely and tightly fill the gap.

Lockwasher is a standard split lockwasher.

Thanks, Joe. Technician is trying to tell me that with the castle nut and cotter pin a lock washer is unnecessary...time to find a new alignment shop.

[Joe L.]

Re: '67 Torque Control Arm pivot assembly

Thanks, Joe. Technician is trying to tell me that with the castle nut and cotter pin a lock washer is unnecessary...time to find a new alignment shop.

Leif-------


In general, he's right. Lockwashers are VERY rarely used in conjunction with slotted nuts (incidentally, these are slotted nuts and not castle nuts). However, since GM used them in this assembly, why not do it the way they did it? I mean, how much do lock washers cost?

[Leif A.]

Re: '67 Torque Control Arm pivot assembly

Leif-------


In general, he's right. Lockwashers are VERY rarely used in conjunction with slotted nuts (incidentally, these are slotted nuts and not castle nuts). However, since GM used them in this assembly, why not do it the way they did it? I mean, how much do lock washers cost?

Agree...and, thanks for the correction on the type of nut used.