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Discussion Starter #1
Hey guy's I have a question for ya.
How do you trouble shoot the differnt problems in the rear axle??
The reason that I ask is all the info that I have found on the web so far (what little there is) really is'nt to specific.
What I have is a loud, hard clunk sound that shakes the car whenever I start to roll away from a stop.
It also makes the car fell like the rear end is swaying back and forth until I get to about 10-15 mph??

Are there any good books out there that contain ifo on how to trouble shoot our corvette's?...Got Chilton's and Hayes...

One more thing how involved is it to change the U-joints in the half shafts....Chilton's make it seem a snap??
Thanks for the input
This is by far one of the best vette forums out there :cool:
Art
 

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I've never messed with the u-jopints or half shafts, but going by the looks of things it can't be too tough a job.

For you clunk, and the fact that you say the car sways at first, I'd think something is amiss around a trailing arm.

Suggest you block it up and have a looksee. Might be a worn and shattered grommet, or a bolt out someplace. I wouldn't drive again until I fixed that puppy.
 

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Discussion Starter #4
My C3 is grounded until I figure this out

Thanks for the info guy's this C3 is grounded for now.
Do you know of any non-destructive (don't have to tare it all apart) method to evaluate the condition of these components.
As well as any good serivce manuals/books that a c3 owner should have?
Thanks
Art
 

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Re: My C3 is grounded until I figure this out

cyclonejack said:
Thanks for the info guy's this C3 is grounded for now.
Do you know of any non-destructive (don't have to tare it all apart) method to evaluate the condition of these components.
As well as any good serivce manuals/books that a c3 owner should have?
Thanks
Art
With rear up on blocks, and the tires off, I'd start by looking everywhere that you think a bolt should be, and look for worn or missing bushings. Try to make stuff move by hand back and forth.

The Haynes book and others like it (PepBoys, Autozone, Sears) are not all inclusive, but they're good enough for most repairs.
 

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Re: My C3 is grounded until I figure this out

cyclonejack said:
Thanks for the info guy's this C3 is grounded for now.
Do you know of any non-destructive (don't have to tare it all apart) method to evaluate the condition of these components.
As well as any good serivce manuals/books that a c3 owner should have?
Thanks
Art

Before you take that puppy apart you could try one relatively inexpensive fix. I had a '78 Vette for 19 years and at one point I was sure the rear end was falling out of it. Whenever I pulled away from a stoplight it would chatter and the car would bounce around. It was especially bad on hot days. Anyway, a friend suggested this fix:
- drain as much fluid from the rear end as possible. Since there is no drain plug, you need to go in through the fill hole with a siphon.
- refill the rear end with a top quality rear end fluid.
- add a bottle of the GM rear end lub additive. Any GM Parts Counter guy will know what you mean.
- once you have the new fluid and additive in, take the car to a parking lot and drive it slowly in circles, ten to the left and and then ten to the right. Sounds crazy but I was told this helps get the additive and new fluid worked into the clutch pack, etc.

Anyway, I did this to mine and could not believe the difference. It was like the rear end had been rebuilt - no noises from the back end, no chattering or shuddering at startup anymore.

Worth a try.

:D :D
 

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BE SURE TO USE JACK STANDS ...................

1. jack the car up and on stands, then grab each wheel at 12:00 and 6:00 and shake. how much movement? if it moves your bearings are bad. then grab the wheel at 9:00 and 3:00 and do the same. if it moves, look at your differential yokes for movement. they could be worn.

2. visually look at each of the 6 u-joints, then roatae each wheel in neutral and watch them. even one that looks good may be bad. consider replacing them any ways.

3. check the bushings on your strut rods...dry? rotted?

4. check the mounts on the differential...dry? rotted? loose?

5. try shaking your trailing arms and watch where they mount . they should be very difficult to move . be sure your shocks are good.

6. as 64vette said....check that fluid. draw out as much old stuff as you can and replace with new...and be sure to add the posi fluid!!!!!!!!!! you can actually add two bottles of posi fluid. after you add the fluid, drive the car in a figure "8" for a couple of times to let it work into the clutches. that is the cheapest attempt to fix a problem.
 

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I had very similar behavior from my '79. It was caused by the rear wheel position. I had the rear bearings and spindles replaced along with many bushings. The right rear wheel would generate a clunk and a low speed whine just after this was done. The strut adjustment was not tigntened enough to maintain wheel alignment and these bushings were worn. I replaced both ends with new bushings, tightened the adjustment and that cured the clunk problem.

I traced the whine in the right wheel to a little looseness in the spindle/bearing.

You can jack up the car a see if there is any play with the tire still on.


HTH
 

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Discussion Starter #9
More info for ya

Last night a drove the car for a while after it has sat for a few days.....
What I noticed was that while the car was cold there was no noise,no clunk,no nothing...As the diff started to warm up it started to clunk, only at this point it was intermitent as I headed back home(only doing local low speed driving) the noise got louder...Could this be the posi???
I asked the old owner if when he had the diff fluid changed did the shop that did it add the "posi lube" he did not know.

So this weekend I am going to drain the diff and add new fluid..
Any sugestions as to the best way to siphon the old stuff out??? As a side note yesterday was alot cooler outside than the day I noticed the noise
Thanks
Art
 

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either have it done at a lube place, or buy an inexpensive vacuum hand pump and do it yourself. most auto parts places carry them.
 
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