TR-6 Trailing Arm Brackets

It's now taken me 2 years, but I finally think that I've got the camber on both my rear wheels right and I thought the list might benefit from some of the 'science' I've applied to the task. There's been some traffic on the list last spring about this subject, but I haven't seen a comprehensive approach to this yet. I hope this helps.

First some background. Last year, I installed new trailing arm up-rated rubber bushings, springs and rubber spring packings, only to find that the rear camber was still excessive - with the driver's side sagging more than the other. This spring, I mixed and matched the trailing arm brackets - using the same mirror-image combination on both sides - the net result being the proper camber on the passenger side with some sag still remaining on the driver's side. Finally, I remixed the brackets on the driver's side alone to get that right. I now have both sides at the proper camber angle - primarily through using various trailing arm bracket combinations.

Since there are 36 possible trailing arm bracket combinations with the one notch, two notch and three notch brackets - either in the 'up' or 'down' positions, I measured the bracket and trailing arm geometry, applied some trigonometry, and then created the following table to determine the range of camber adjustment possible using the 36 combinations. Please note that the camber angle shown in the table is the RELATIVE angle between bracket combinations, the actual angle you'll end up with depends on the camber angle you're starting with. Also note that the negative camber angle DECREASES as you go down the table. By the way, 3U means positioning the bracket with the three notches up, etc.

Here's the table:

The actual angle you achieve may differ somewhat from that listed above because the rubber bushings distort when you force the bushing bolts through to meet the new bracket holes.

I found that it's best to change only one bracket per trailing arm at a time. If you want to leave the ride height alone, change the inner bracket. If you want to raise (or lower) the ride height while changing the camber angle, change the outer one. To use the table, figure out which bracket you're going to leave as is and then find the next combination that allows you to do this while achieving the approximate camber angle change desired.

In my particular case, the combination I ended up with was: passenger side; outer = 1D inner = 2U, driver's side; outer = 3D inner = 2U.

I should point out that it is very possible to change out a bracket while leaving the rest of the rear suspension intact. To do this, place the rear of your TR on jack stands, jack up the trailing arm so that you can support it (and take the spring pressure) with a secure support under the trailing arm, place your jack under the arm where it joins the bracket, remove the bushing bolt, remove the nuts on the bracket to frame bolts, raise or lower the jack so you can get the frame bolts out, remove the bracket and install the new one. Make sure you replace the alignment shims as you found them. There is some grunt work involved in getting the trailing arm back into the new bracket and aligning the bushing bolt holes (I've found that a pipe clamp is a great help in forcing the trailing arm back into the bracket) but the whole job can be accomplished in about an hour and a half.

Couple of cautions: make sure the trailing arm is securely supported while you do this; that rear spring can cause a severe injury if it lets go. Secondly, go this bracket change-out route only after you've renewed the trailing arm bushings, springs and rubber packings as required.

Many Thanks to Brian for his efforts!

Brian Lanoway
73 TR6 CF6985U
Winnipeg, Canada