Lyndwood

I removed the drivers side rear trailing arm assembly on my '74 tonight, went fairly smooth all the nuts/bolts broke free. what bothered me is that all the shims where stacked on the inside of the frame pocket with none on the outside of the TA? Is that normal, shouldn't the shims be on both sides of the TA? I plan on having the new suspension re-aligned when done but wondered if what I found may mean there's' a problem somewhere else I need to investigate?

I will be removing the passenger side tomorrow night so I'll see how the shims are stacked over there.
paul

cagotzmann

It will vary car to car. But the problem you will face there is no where to go if you need more toe-in to align correctly. With out knowing the actual toe settings you cannot determine if there is a problem.

How is the wear on the rear tires ?

doorgunner

Is the driver-side rear tire wearing normally?

Does the camber of the wheel look good?

If so, don't worry about the shims....put them back the way you found them.

Handle the passenger wheel/trailing arm the same way judging the tire wear etc.

Blue Juice

Paul,

Check the lengths of your half shafts to ensure they are the same.

My '76 had two different lengths of half shafts (both 3" diameter). Presumably because a shaft was incorrectly replaced at some time.

You can get two different lengths of half shaft!!!

Don't know why or any other detail because this was a number of years ago, so I can't remember dimensions, but it was a similar problem to what you have found that revealed this. I just couldn't get close to correct toe without almost all the shims on one side being stacked together.

I remember calling a local Corvette guy here (UK) and he dug out some used shafts and started measuring lengths and he was surprised to find a difference. He sent me the length I needed to match the good side that had almost equal shim separation and the other side lined up perfectly.

Easy Mike

Toe is set with the inner shim pack. The outer pack only serves to take up the space between the arm and the frame and keep the inner pack tight.

It is unusual for a car not to have an outer shim pack, but not necessarily impossible.

Did you keep/index the inner stack before you removed it?

Lyndwood

yes I kept the stack so I can replace them with new stainless ones. I am just unsure if I should just put shims in equally on each side during re installation & let the alignment guy reset them how they should be or put them all back in on one side again?

I can't use the tires as a guideline as they had been rotated around by the previous owner (on & off) several times as it sat in his garage so he thinks the tires are mixed up (front to back)? 2 tires are worn on the inside pretty bad but not sure if they were on the front or the back when it was last on the street years ago?

Easy Mike

Install the inner packs based on what you took out. That gets you back in the neighborhood of correct toe.

Use the remaining shims to pack the outer space.

You can add or remove as needed at the alignment shop.

Lyndwood

Ok heres an up date from tonight's dis assembly of the passenger side.
and other things I found?
removed the passenger side trailing arm & found all the shims stacked on the outside only, so the drivers side had all the shims stacked on the inside of the arm and the passenger side had all the shims on the outside of the arm? also noticed the center mount bolt under the rear looks like it's cocked on an angle, could the rear be shifted?
the guy I bought the project off of said it needed rear trailing arm bushings & maybe hub bearings, so much that he didn't want me to test drive the car.I bought it anyway since the frame was cherry & it ran good + he through in $500 of new rear suspension parts from corvette america with the sale (new rear struts,ta bushings,shocks,shock mounts + all new hardware).
I found both T/A front bushings intact & un-worn? the hub bearings have no play & spin freely with no noise or binding? I did find worn lower shock mount rubbers,worn/torn torsion bar rubbers,1 blown u-joint on the p-side half shaft, 2 loose (hand tight) u-joint cap bolts on each side of the dif? 2 new (cross threaded) brake hard lines off the calipers & when I removed the calipers the brake pads fell into pieces on the floor?

so I am glad the T/Arms aren't a write off.still gonna re-bush & paint them, but it bothers me that the shims are all on one side (the same side) of both arms & the center mount bolt is crooked?

cagotzmann

How do the rear differental carrier bushing look. This is the long crossmember mounting to the body / frame and the differental. If this carrier looks square the differental cannot shift. I would look at the frame to see how square it is. Until you reassemble it will be difficult to determine what else could be wrong.

You can do some simple alignment checks with a laser level and a bar across the rims. Then measure the distance from the front wheel hubs. A perfect rear wheel trust alignment will have equal measurements both left and right.

You might also want to spend some time on learning to do a DIY wheel alignment to further investigate what might be wrong.

The other thing to check is make sure both half shafts from the diff to the trailing arms are the same / correct length. Some people have reported PO repairs have used the wrong length half shafts.

dugsgms74

Hmm, alarms are going off! If the toe is set to one extreme on one side and the other on the opposite side something is wrong. Checking the half shaft length is a good idea but it sounds like something is bent. Hopefully not the frame but either the frame is bent or the diff is pushed off to one side for some reason, you'll need to do some looking around to find the root of the problem.

Lyndwood

ok found some more info out. the half shafts are the same length but the lower strut rods are 1/2" different in overall length. the passenger side one is 18.5" long and has big cast ends 1.750"OD around the bushing. the drivers side was 18" over all with 1.50" OD cast ends around the bushing?

the differential carrier bushings look fine and the cross beam they are part of is parallel to the frame just behind it. It is equally spaced from end to end & side to side, nothing looks out of place. Of course I didn't take any measurements but will do a corner to corner off the beam to a fixed point up front later this week, it should be the same length I presume.

Looking at the rear diff from under the car it is in the center as is the center support, what is cocked on an angle is the bolt that goes through the support to the top & bottom rubbers. Maybe the rubber supports are just shot and causing the bolt to be off center?

Lyndwood

ok my last question is do I or don't I have the TA hubs pulled apart to do bearings? the last owner thought the hub bearings may be bad because he heard a lot of noise in the rear,he also thought he needed TA bushings? after disassembly I found the bad u-joint on the half shaft + the loose half shaft u-joint cap bolts & worn out strut bushings. after removing the T-arms both front bushings are intact & fully functional, the hubs spin free with no binding & have no play, they feel great. I also found he didn't have enough wheel spacers for the american racing wheels he had on the car and the rear rotors were hitting the outer corners of the caliper, cut a gouge in the backs of the wheels ,must have made a hell of a noise!

plan #1 was to send them out to get refurbished and it would set me back $800 + the shipping. plan #2 is now to wire wheel and repaint the T-arms, install the new TA bushings,new equel strut rods & rear shocks I got with the sale of the car and put the saved money into all new o-ringed calipers/pads/hoses & rotors (kit from zips).

one T-arm was a GM replacement at one time,still has the sticker on the arm,the other looks to be original?

Lyndwood

both tA shims are to the same side. on the drivers side they are on the inside of the arm, on the passenger side they are on the outside of th arm.

doorgunner

My '68 project was similar. The half shaft was jammed on the passenger side and sloppy on the driver side. The frame measuring points were square. I reluctantly relocated the differential to the driver side 1/4"......everything lined up correctly.

NOT saying that's your problem though.

mikem350

Can you explain HOW??

doorgunner

I wouldn't advise anyone to do this.....it cured my specific problem.

I removed the differential crossmember which took 2 hours/using a six foot long "breaker-bar" attached to a two foot long tie-rod separator-tool.
I placed a transmission jack under the differential after I disconnected and removed EVERYTHING that was bolted to the differential.
I removed the two large bolts that held the diff. crossmember to the frame.
I allowed about three inches of space between the transmission jack and the bottom of the differential to give the diff. room to "drop".
The part that took an hour was separating the crossmember rubber bushings from the frame which took all my weight on the breaker bar.
The differential dropped onto the transmission jack.....I lowered it and rolled it from under the car.
I marked the crossmember with an arrow to show the direction the differential needed to be moved in.
I unbolted the differential from the crossmember.
I scribed a line across the center of the crossmember.
*In my case to correct my problem*................................ ..............
I scribed a line 1/4" from the two left OUTER edge bolt holes.
I used a tungsten carbide "cutting tool"to elongate/slot the original holes to the edge of the scribed lines.
I scribe a line 1/4" from the two right INNER edge bolt holes.
I elongated/slotted those two holes



I set the crossmember on the differential ....arrow pointing the correct direction.
I threaded the four bolts in partway into the diff.
I used a rubber mallet to bump the crossmember slots against the bolts.
I torqued the four bolts.
I measured the modified differential to make sure it measured side-to-side as it now should.
I reinstalled the assembly using wheel bearing grease on the two rubber crossmember alignment bushing to keep them from seizing in the future.
The halfshafts (which were identical in length) went into place perfectly.

I think I listed everything in the correct order.

my 76 ray

I'm a fan of if it ain't broke, don't fix it. But I do look at the effort to do it again. For example, I had my body off the frame so I replaced the brake lines and fuel lines because they would be so hard to replace once the body is on. It's your call but I would not have the trailing arms rebuilt since they sound like they are good. I'm assuming that since you have them off the car that they won't be rusted on if you need to remove them again.

Lyndwood

i decided to have them rebuilt because one looked original and the other was obviously replaced at one time, both felt good but the older one needed to come apart to be blasted & cleaned anyway so why do one...do them both and have piece of mind that they are done.

doorgunner

Probably a good decision on your part......

my project's T.A. bearings felt/sounded smooth......I took them apart anyway.....the seals were worn......the 44 year old bearing grease was starting to harden!