speedjohnson

I've got a loose left rear suspension...and I can't find the cause.

With the car jacked up, I can rock the wheel some 3/16" front to back and 1/4" up and down.

I installed new hub bearings a few months ago...and the freeplay does not seem to be at the bearing. I've got a new set of sperical bearing trailing arms/strut rods/toe rods and these all seem tight. The freeplay seems to be coming from the hub assy, behind the bearing...or possibly from where the axel meets the differential (Dana 44). I've re-tightened the axel nut with no effect.

It's allowing enough wheel deflection that I'm rubbing the inside edge of the tire on the outboard portion of the trailing arm bracket when the car squats.

I've got the car at the track this weekend and am just hoping to get this figured out before my race group goes out.

Any other ideas?

ToniH

You need to get under the car when somebody else rocks the tire. It should be quite easy to spot where the loosenes is. You need to isolate the problem to somewhere before any repairs or even smarter advice can be given.

See if the whole axle moves in and out, then it is possibly the Dana with a bad bearing or maybe a clip that holds the yoke (if there is one, not expert with rear ends).

But like I said when your under there you should be able to see what part moves and what does not.

h rocks

First of all, don't track the car until you figure it out!! If you have THAT much freeplay, something is very wrong, and dangerous. Even if nothing detaches from the car while underway, you will have an unbelieveable amount of rear steer. I would normally call it bumpsteer, but your situation is inherent, has nothing to do with suspension travel.

To state the obvious, did you absolutely get the hub seated correctly when you installed the Torx bolts from the backside? How about the large (39mm?) hub nut? (160#/ft of torque) For there to be THAT much movement in both directions leads me to believe that something's not attached properly. Let us know what you find.

speedjohnson

Yeah, if I only had a pit crew.

I did just now get some help. I do think that this might be coming at the Dana end by what I can see. It looks like the axel acts as the upper control arm in this suspension configuration. What holds this axel in place?

This will be a non-chicane race and will be some fast strightline speeds...would hate to loose an axel. sj

ToniH

OK, I checked from the factory service manual and there is "a yoke shaft snap ring retainer" which holds the yoke to the rear end. Also a worn yoke bearing could be causing this.

BTW. the spindle nut h rocks mentioned earlier is 36mm.


[Modified by ToniH, 8:30 PM 7/2/2004]

94 Trip

Check your U joint. I replaced the hub only to find out it was the $17.00 U joint instead.

MtlSphere

Ouch! I hated to read about that! Last weekend while lowering the rear end of my Vette I noticed the left rear wheel had excessive play on all axis'. Thinking wheel hub I called Napa...$202.00, then Autozone, $149.99, then logged onto ebay...$117.00 with shipping. It arrived Thursday and I'm just getting up to install it in a little while. It's been raining for days here and there's supposed to be a break. I want to drive my baby! But I would hate to have just installed a new hub only to find the ujoint was bad. I'm thinking I would have noticed that while I was under the car. The really interesting thing was that the hub was giving no indication of impending failure. Other than a bit of a handling problem (thought I was just due for an alignment), there was no noise usually associated with a failing bearing or u-joint). Are these things built tough or what? I'll post my findings later this evening.

Frodo

I'd like to add my 2 cents worth about u-joints and worn hubs. About 6 months ago I replaced all 6 u-joints and since logged less than 5k miles on them. A couple weeks ago I found a bad left rear hub, LOTS of up-down play, and while replacing that I had the half shaft out to make things easier. Well... one of the u-joint bearing caps fell off, hit the floor, and some of the needle bearings fell out. As I was trying to reassemble the bearing I noticed an odd wear pattern inside the cap, heavy wear on one side. I took the other cap off and found similar wear in that one. My guess is the bad hub bearing threw the half shaft out of center causing the shaft to put excessive wear on the u-joint. At any rate, when changing the hub it might be worth the effort to inspect the u-joint caps for excessive wear.

MtlSphere

I had a ful day with a lot of irons in the fire but I did make time to finish the Vette.

I found upon removing the wheel, cotter pin and retainer that the spindle nut was loose. I bitched a blue streak about that one but I was hoping that all I had to do was tighten it up to take the play out of it. Torqued it down still had the play...rats!

I pulled the spindle nut and gave the hub a wobble. The flange came off in my hand. So now I know what the inside of a rear bearing hub looks like. I replaced the hub with the unit I obtained off ebay. Perfect fit! Torqued everything back into place and took her for a tester. As I was hoping the handling issue I had before is gone. The car tracks straight like it should.

All in all I don't have the feeling that changing the rear bearing hubs is a very difficult task. I put G&R's greatest hits in the CD player and I was finished before it went thru twice. Compressed air saves so much time!

speedjohnson

THANKS GUYS!!

It was the inboard u-joint...I likely would have never found it without some help from all of you...as it's realy buried inside the knuckle.

I swapped the joint out at the track...re-aligned the car with a string line...and went on to putting in the fastest race laptimes that I had ever done!

I qualified 4th on grid behind a Porsche GT3 Cup car, a Viper Competition Coupe and a Monte Carlo. I pulled the Porcshe and the Viper off the line and then was able to put some lapped traffic between us. I finished 2nd in Super Production...How's that for a 20 year old C-4? WoooHoo! speedj

MtlSphere

Too COOL!

I love to read about Corvettes passing Porsches!

I think I would take the car to the alignment shop and just have them measure the setup you put on the car so you can reproduce it the next time you race!

speedjohnson

I'll e-mail you a 3mb video clip if you'd like to see the start...up close and personal.

Again, thanks all for the tech tips. sj