f16nooch

I had rebuilt the rear end of my 79 a few years back due to a seal leak off the right side of differential. Put new trailing arm bushings, shims, half shaft u joints, leaf spring, strut rod bushings, shocks, etc. Things have been fine back there for a few years. Lately the power steering seems to leak at the control valve and also has what I can describe as a "dead spot" where I can turn the wheel and not get any steering response until I turn a bit more. Nothing too dangerous, just noticeable sloppy play of steering wheel with no front end response.

Just recently, if I accelerate, I feel the rear end sway to the left and if I decelerate, the rear end will sway to the right. Read a few posts about possible positrac issue, so I had replaced diff fluid with the Lucas 85W140 and 1 bottle of the GM additive. Went for test drive afterwards and did multiple figure 8s to lube up both clutch packs. Still get the rear end swerve. Also, inspected both trailing arms and shims, cotter pins, bushings, bolts; all seem in place with no anomalies. Also, just put 4 new BF Goodrich TAs on, but the problem existed before the new tires.

My question: can this be related to the power steering issue or am I overlooking something? Can it also be a rear wheel bearing issue?

Thanks for any responses in advance.
Nooch

DUB

I had a Corvette in my shop several years ago that did the exact same thing...and when I finally got deep into it....the four nuts that hold the entire trailing arm assembly together were all loose....and allowing one wheel assembly do do whatever it wanted.

DID you install your own trailing arm bushings...and if so...what type??? Rubber or poly??? And if they are the rubber design...and you did them....did you use the correct tool to compress the bushing together and stake/flare the inner sleeve as designed???

DUB

f16nooch

According to my records, I installed the "bushing kit, trailing arm, Poly, 63-82 w/sleeves from Ecklers, part number A7147.

Avette4me

Take a good look at your rear spring.

f16nooch

Interesting you say that. As part of the rebuild, I installed a new leaf spring from Mid America, part #602860. My old factory spring was a 10 leaf while the Mid America one was a 9 leaf. In order to keep the rear end at an acceptable sitting height, I had to install the extended bolt kit at each end. The extended bolt (Mid America part #602850) was 7.25 inches vs the stock length was 6.5 inches (part #602848). Not sure if that is what you had in mind.

Also, I've owned the car since 1980 and about a year after owning the vehicle, I spotted the leaf springs separating like a deck of cards where one of the bolts near the diff had come loose from the mount. I had fabricated an additional bracket on both sides of the spring to prevent that from ever happening again.

I will check it over again.
Thanks.

Oldguard 7

Could the c clips come off from the diff side yokes? I ask b/c he stated he had this swerve issue prior to installing new tires.

Avette4me

That type of thing is more what I was thinking.

f16nooch

I will definitely confirm that as well. Will get back to you.

thegazman

I had a similar problem on my 79 and this was causing it.

MajD

Before I rebuilt the rear end in my 79, the rear would picth out to the right on gradual cornering. When I got into the project, I found out that the two drivers side bolts holding the diff to the cross member had backed almost completely out and there was about 1/2" or so gap between the diff and the cross member. Don't know if that was causing the problem, as the yokes were also worn out, but it may be worth checking out.

OMF

Check to make sure the trailing arm spindle bearings are still good. Jack it up and check for wheel movement at 12 & 6 o'clock.

f16nooch

Thanks for your findings. Currently have to head to China for work, but will jump into this when I get back.

f16nooch

Roger that; will check for that play.

f16nooch

Dub,

Saw you were online and wanted to ask you a question about a trailing arm rebuild. I was looking into this rear end swerve problem and found that both of my TA bushings had disintegrated which looked like whitish blue black parts all broken up sitting in the frame hole where the TA bolt passes through. I had installed these Eckler poly bushings back in 2005 and really only drive the car a few hundred miles each year which surprised me that they would so this. Did have the rear end aligned after all work was completed back then.

I had installed a new steel leaf spring as well, but unfortunately it forced me to have to use 8 inch extension bolts to even make the ride height close to what it should be, but it was still slightly high. Not sure if this contributed to the rapid decay of the bushings.

So I have both TAs out again and planning on installing VB&P poly bushings as well as a single mount monospring from them of the 300# flavor. I have read many of your posts and wanted just to confirm the poly bushings do NOT require extreme compression before staking with the flare tool, only a light pressure according to the VP&B instructions. Also, use shims as required on the bushings to attain a 0.010" gap between outer washer and edge of poly bushing? Planning on reinstalling shims the way they came out which was pretty much equal distance on either side of the TA as they sit in the slot and this was for both left and right wheels.

Any other words of advice or wisdom would be greatly appreciated and thanks for your time. Beers on me if I ever come to NC or if you ever come through Memphis.

Nooch

OMF

OK I'm nowhere close to DUB on the rebuild stuff, But I do know how to hold a wrench.....
I just did this on my car, so you remove all the inner parts and leave the outer metal sleeve pressed into the TA. The kits come with some lube, and say to put it on sparingly, but I made sure everything has a nice healthy coating of the lube, I used a combo of the sticky stuff lube and some white grease.....I think DUB has his own recipe for lube too IIRC. Assemble the parts (poly bushings and steel sleeve inside the bushings) and use a large flat washers that come in the kit on either side of the bushings (lubed well also.) No Staking is required with the poly bushings, just lube, assemble, install shims, and tighten.

Hope that helps...

f16nooch

Thanks for that and it is pretty much the way I read it. Just can't seem to understand why the poly bushings I installed back in 2005 had disintegrated in such a short time with very limited driving on them.

'75

There have been many reports of poly bushings ending up like yours. Also most don't recommend using poly in the trailing arm due to it needing to twist as it pivots.