TR6 Suspension Bushing Replacement.

[sqbsprite]

I finally got back to my suspension rebuild. I did not get much done during the Holidays. What I thought was a good repair to the diff mounts turned out to be not so good. The welds were OK but sloppy. I spent some time reworking them to be smoother under the rubber mount.


The bead of weld on the RH side was directly under the rubber mount. I also found a shop to weld my trailing arm that was cracked.


We added a gusset on the back side.



I glass beaded the arms and painted them silver using Rustoleum industrial aluminum coating. It looks like bare aluminum.



Here is a photo showing the new adjustable mount compared to the old. The bolts that hold the bracket to the frame are actually a little longer, so there should be no problem adding additional shims for toe-in adjustment.

I have the differential installed and next weekend I hope to get the trailing arms back in. I am going to take time to clean and paint the springs and brake backing plates. I had already rebuilt the axles last year, so they still look good.

 

[sqbsprite]

I have re-installed the trailing arms and in case anyone comes back to this thread, I wanted to note something that I think I saw elsewhere on this forum. When installing the adjustable mounts, do not follow the included instructions regarding the orientation of the adjusters. Make sure the adjusters are mounted to the inside of each trailing arm. If you mount the inboard adjuster toward the outside of the arm, it will hit the frame when installing the arm.

Now regarding shims; mine had too many IMO. the RH had 5 on the outer and 3 on the inner. The LH had 4 on the outer and 2 on the inner. I would think that it would have been the difference of 2 that was important. I guess whoever made the adjustment just added shims vs getting the net difference correct. Does that make sense? Either way, with new bushings I'm starting out with 2 on the outside and none on the inside. This should guarantee toe-in to start. Specs say 1/16" toe in. I'm hoping it's square with the frame so the thrust angle will be neutral. Any way, I'll sort that out when I get it back on the ground and check the measurements this weekend.

Same with the camber, I'm starting out with the adjusters in the center.

 

[poolboy]

You knew those shims were there not only for toe-in adjustment but also to equalize the left and right wheelbases ?

 

[sqbsprite]

Thanks Yoda. I'll be checking that as well, but there is no way to know what it left the factory with. I'm expecting to see a discrepancy on the RH side because I thingk someone hit something hard enough to crack the arm at the hub flange. One hole in the frame for the bracket looked a little oblong. That bracket had the most shims under it (5).

I would think that the factory would have welded the frame on a jig and it should have been really close. But, I have never seen one that I can know for sure had not had the shims messed with. I'm open for any and all advice. I'm going to see how close I can get it and then take to a shop to check alignment

 

[sqbsprite]

Okay, It is back together and ready for a road test. Here is what I found when I first took it off the stands and put it on the ground. After bouncing it up and down and rolling it back and forth to get it settled, the LH side looked like a VW with the engine removed. I measure 3.5 deg of positive camber. That might not sound bad but it's a 1" difference from the top of the wheel to the bottom. The RH side looked pretty good with just about .9 degress negative. I did not even bother checking the toe in at this point because the camber was so bad. I adjusted the LH side by running the adjuster all the way down on the inside pivot mount and checked it again. It was about half as bad. So I ran the outside adjustment all the way up. This got it to about .4 deg. positive which is within spec. For the LH side I was able to adjust the inside mount only and get it to 0 deg. I am puzzled at why the LH side was so bad without seeing any apparent issue with the frame. The LH side had too much negative with the old bushings.

Next was toe in. Here was good and bad news. The toe in was 1/16" which is good. The bad news is that both rears were angled to the RH side. This problem existed before the rebuild. and I thought it was due to the incorrect number and location of the shims. My starting point was 2 shims on each inside bracket. Since the toe in was correct, I added 2 more shims to each side but on the inside of the LH side and the outside of the RH side. This now looks pretty close. The road test will let me see if it is crabbing or tracking straight. If needed I will tweak things some more before taking it to an alignment shop.

Used a square to check measurement at bottom of wheel rim and top to calculate camber.



Using a toe-in gauge. simple but has proven to be fairly accurate on my other cars. The photos do not show the actual measurement. I posed them later without resetting the gauge. I know somebody will call me out on it if I do not explain.

 

[sqbsprite]

Today's road test went well. I followed the car with my wife driving. It tracks straight and the camber looks good. The ride height seems a little taller in the rear. The poly spring seats are likely the reason. I re-tightened all the bolts and will check them all again once I start driving it this spring. Now the front is in the air and the dis-assembly has begun. I wonder what surprises I will find. The PO had replaced the shocks and sway bar links, but I think the rest of the bushings need to be replaced.