The 77 is making a clunk, clunk, clunk noticable on the drivers side, Vibration at 50-60mph & Rear camber is way out , much greater on the pass. side. History of repairs are in order from oldest to newest.
HD rear spring & diff cover. ( the rabbit ears were cracked on the original) also adj strut rods installed.
Rear end Diff rebuild by Corvettemasters on 8/99 which included new posi clutch pac, but the yokes were not changed as they were claimed to be in good shape (orginal).
Rear bearings by Van steel: done 8/99 along with rotors & calipers.
Brute force u joints for half shafts & drive shaft 7/92,
Replaced pass side control arm bushing myself with the kit that lets you crimp the ends by nut & bolt. ( you know which ones if you have researched this job yourself). The drvrs side wasn't removed as I ran out of time & energy( & sawzall blades) with the pass side.
All was well & good & I figured that I would never have to deal with that part of the vette again for at least a good 10-20 yrs with a little luck. Wrong!
Now I have this clunk & vibration, Camber is way out of wack. I put the car up on jack stands & ran the motor & placed her in gear to see the wheels spin. I know they were hanging but the noise was very prominent and I could see the tire (new tires today with a half assed alignment) moving up and down (6 oclock to 12 oclock ) with each rotation. The pass side had very little mvt when spinning. I removed the tire on the drivrers side & still the same. The u joints visibly looked good but the control arm bushings were really worn as I was able to obtain a lot of mov't by hand. The bearings are fine. So i'm thinkin 3 things wrong here.
1. One or 2 u joints are gone.
2. the yokes are gone.(this is what I think).
3. The rear bushings are so bad that its causing the camber to be so far off that its causing these problems.
4 or all of the above as my luck goes.
Any help & thoughts are welcomed.

 

Replace the lower control arm bushings, yokes can only wear a fraction of an inch and wouldn't cause the camber symptoms you describe. My suspicion is the control arm adjustment cams are not holding your camber settings. Get the camber adjustment replacements that do away with these cams and use threaded ends that allow adjustments similar to ties rod ends, VBP sells 'em.

 

I also recommend tossing the original cam adjustable strut rods for heim ends on an adjustable center link. You can buy the pieces from race parts house and save a few bucks. Email me if you are interested in a source.

 

I already have the threaded end adjustable strut arms & they are adjusted way in to pull those tires in.mY best adjment now reads -2.9 camber to the drivers side & -2.8 for the pass side. Do you think that the bushings & not the yokes would cause the symptoms the car is displaying?

 

Not a good idea to run the thing with the wheels hanging down, it puts a lot of stress on the u-joints and doesn't give you an accurite pic of what is going on when the car is rolling. To do that you need to get jackstands under the TAs so the wiight is carried on the TAs

 

Good point. I realized that after I did it. I'm thinking of removing the half shafts and running it to see if the noise originates from the diff. but also wonder if it will as there will be no weight or resistance to the yokes. I can though see what kind of play I would get on the yokes . Would they pull out fron the diff case at this point if the c clip was gone or do I still need to remove the diff cover.. I'm wondering if the trailer bushings are the culprit here.??

 

It sounds to me as if you have several things to address here. I usually try not to change things that don't need to be changed, but it sounds to me like you have enough variables working against you that you need to start over by replacing all the bushings in the rear susp. Then you know everything is good and you are not just shooting in the dark.

As for those adj. rods; I don't know if they are worth anything or not. I had a car with them and they walked out until the car had a severe vibration anything over 45 mph. When I got home I found the problem and tightened the lock nuts; ran the car a few weeks and guess what. They had backed off again. I have since sold that car and did not run out to buy those adj. rods for my present car. I am just not convinced they are worth the trouble.

 

Side yokes are easy to check and you dont need to run the car. - jack the rear of the car up in the air and have an assistant grab the tire at 6 & 12 - have him rock the tire.

• If there is more than 1/8" (and many consider this excessive) of yoke travel in and out of the diff - the yokes are worn.
• check other locations as well - is there slop in the lower strut rod connections when doing this
• look at the halfshaft flange at the trailing arm and watch closely...does this flange move independant of the trailing arm? if so there is some bearing wear

 

When you say control arm bushing I think of the bushing where the arm is attached and pivots at the frame pocket. You say you replaced the bushing on the passengers side only. I must assume you also re-shimmed it and replaced the bolt with new, right? The driverside was started, but left due to stubborn shims, correct? You don't say anything about checking movement of the bearing assembly by checking tire movement in the 3-9 o'clock direction. The car obviously needs to be up on stands while you do this. Then, check movement moving the tire in 12-6 o'clock direction. This will give you an idea of your yoke condition. I assume all the shims are in place on both sides of your T-arm pivot bolt? If it is shimmed properly, you will not see more than slight t-arm movement when applying alternating force in the 12-6 o'clock axis.

The noise could be just about anything. If you can get the weight on the t-arms with the wheels off it will help you in your effort. I placed a 4X4 post on jack stands and under my t-arms to observe everything in the natural position. Let the t-arms carry the weight and compress the spring. I recommend putting stands under the frame corners as a back-up as well. With the tires off you can turn the IRS with the engine running and observe. While the car is in this position you can do an alignment using the rotors. If you have a laser level, place it on the rotor and shoot a beam along the frame and measure. Keep the beam parallel for a dead straight track like for drag racing. Place the level on the rotor on 12-6 o'clock axis and check for level. Of course your car needs to be on a level surface. Both beams should be the same distance from the frame.

Your adjustment of the strut rod 'way in' as you describe is only compensating for the true problem. Set everything as it should be and identify the part that is the problem. Keep a close eye on movement in the t-arm mount location in the frame pocket.

 

I did the trailer arm bushing on the pass side using the same measured thickness of the old shims for both sides of the bolt . The bearings are in great shape as no mvt was seen at that end. The yoke has some small amt of play but I need a 2nd person to move it for me so I can try & get a measurment. I have discovered a LARGE amt of movment to the trailng arms in the 6 -12 oclock mvt originating from the bushing area. So now I am almost sure that this is the cause of the problem. Even if it isn't they need to be repaired anyway so this will be my next move.

 

You could probably just pull the old shims and replace and realign, but it would come back to haunt you. This is why I prefer to replace everything new at one time and be done with it. Good luck and keep us posted on your results.

 

In Hindsite It would be the right thing to do I'm even going to redoo the pass side again as I think there may have been a failure on that side also. (very loose) I'll update.
Thanks guys

 

When you install the shims, plan on tapping the last one in with a hammer. Everything gets loose after awhile anyway, so better to start with a tight fit. If you do not do this, you will not be able to torque the t-arm pivot bolts without drawing the frame in to take up the slack. Honestly, I believe too much importance is placed on the shim pack. Generally, an even stack on each side does the job. That IRS job is a can of worms and a real PITA. Since you will have it all apart anyway, might as well do a clean-up with fresh paint. This way there will be a visual enhancement for you effort. Good luck!

 

The spindles are fine The big culprit was the bushings in the strut rods. The ones on the inner side were completly gone. Bare metal was all that was left. I got a set of urethane ones from ecklers & put them in. Bingo works fine for now wheels are cambered upright no noises. . The only problem I will have is that the bushing set isn't the right size. the outers fit great around the shock mounts but the inners are also for that size bolt not the smaller diameter of the existing bolts so I will have slack until I can locate the proper size bushing, until than all seems well. What a PITA it was locating these. I had it into a local mechanic that said he couldn't find them so I took the car back & did it myself. I went to Ecklers today 50 miles each way only to be dissapointed by the size error, went to Napa after a phone conversation which they said that they had it in stock only to go there & find that it wasn't even for the struts, & than to another big auto parts store that was useless .Thats when I put in the Ecklers set . All day long on this frickin thing in 95degree heat. I lost 4lbs in sweat..really. I'm going to have to order a set of bushings from Van steel or VBP & wait till it gets a little cooler before doing this job again. I'm getting to old to work in this heat (56 yrs old) . Oh yea it cost me $28. for the bushings & about $20 in gas & tolls but still better than the $375 the guy in the garage wanted to charge to fix it.

 

Glad you were able to find the weak link and replace.