Bad Sounds

[blasterfdc]

I have a 69 coupe with a terrible sound coming from the right rear tire. It is a clicking sound that increases with speed. Before this started when I would start off or go around corner slow the car would kind of jump or slip (hard to explain) I thought it was the rear suspension until this clicking started. Is it the half shaft u joints or is it wheel bearings??? I jacked the car up to check for wheel play but I don't have very much vette experience yet. The wheel has some movement when grabbed at the 12 and 6 o'clock but it looks like the whole trailing arm moves.

any help would be appreciated, just want to get back on the road.

 

[78SilvAnniv]

Hopefully other, more experienced members will chime in soon...
My first thought, since you say it is clicking and would sort of jump around corners sounds like a brake is hanging up. Does it feel like the R rear is locked and then when enough force is applied it loosens and rolls freely?
Perhaps it is the emergency brake?
Good luck with the problem.
Heidi

 

[Yoda]

blasterfdc ~ Welcome to the Corvette Action Center Community ~

Blasterfdc,

Start with something simple... try changing the rearend fluid and BE SURE to use the GM positrac additive Give that a try and see if it helps. I get my changed about every 3 years. The local Chevrolet garage does it for about $24 with the additive. My 81 doesn't have a drain plug, the plug is near the top of the housing and a real pain to get to and remove the fluid..

To test the bearings and spindles the rear end needs to be "Loaded" .. which means the rear tires need to be off the ground then you'll need to jack up the cross spring at the tire side to normal ride height before grabbing the wheel at 6 and 12, then 9 and 3 o'clock to check for movement. You get kind of an idea by checking it without loading it

Sorry for the rapid fire answer, but I have someplace I'm suppose to be here before long ..

 

[CQRT]

Best guess is outer spindle bearings?? You're generally right to check the 'wobble factor' but I think that's relative... If it gets faster and louder with increased speed, that's my vote. And a word of caution - -don't drive it very far, or very fast!
CQRT

 

[kennels]

Had the same problem. Turned out one of the springs on the parking brake had broken and was floating around in the drum.

 

[BeaterShark]

How sure are you it is from the right wheel area? Posi clutches can make clicking noises, and you did say it started while turning. A fluid change *may* quiet it down.

A U-joint could easily make clicking noises, but I'm not really sure how to diagnose. Sometimes it's obvious and sometimes it's near impossible to tell when there about done, although with the extremety of the noise, you should be able to see if there is a problem.

I don't believe the wheel bearings would make a clicking noise. A screeching or griding noise, yes.

How much of the history of this car do you know? Tell us as much as you can.

 

[Jack]

clicking sound that increases with speed. Before this started when I would start off or go around corner slow the car would kind of jump or slip (hard to explain) .

The jump-slip while cornering is classis symptom of posi-trac unit problem. As rare81 said ... change out the diff grease and do add the posi additive ... it's kinda hard to get to so $24 is a good deal. Drive it only far enough to get the grease & additive renewed ... that may solve both slippage & clicking ... then again, it may not.

The clicking may also be from the posi ... but could be ujoints / rear wheel bearings.
JACK:gap

 

[78SilvAnniv]

Not to dismiss any previously mentioned suggestions...

In the past I've had problems with my u-joints, rear wheel bearings and side-yokes/rear end gears and I don't associate a clicking sound with any of those problems I experienced.

My u-joints made sounds of a continuous high squeak. Like: squeak-a, squeak-a, squeak-a that would increase or decrease with speed.
The rear wheel bearings would sound like a low humm, sort of a grinding-humm, that would change in intensity from vehicle speed and direction, like slight curves on the roadway.
The side yokes made the most noise. (Are rear bearings involved in this, too? I do know my rear gears needed to be changed at the time we replaced the yokes.) This noise was a groaning, moaning, popping noise coming from the rear of the vette. Most noticeable when starting from a stop and turning corners.

I do agree a rear fluid change is a cheap maintenance item and possibly a cheap, quick fix, too...but I'd still check out the possiblity of the parking brake before going on to more expensive items.
Heidi

 

[blasterfdc]

bad sounds

Thanks guys, still diagnosing, I never thought of rear end problems.
The brake doesn't feel like it is locking up....
The sound is deffinately coming fromt the rear right tire area.
Never thought of the emergency brake, mine doesn't work so that is worth looking into. Thanks for that direction Kennels

and Heidi thanks for that input, it does sound a little like a squeak-a maybe. I think I am going to try to shot gun a few things before tearing apart the wheel bearings.

ie rear end fluid change, u-joints and grease the wheel bearings. Those should all be fairly easy task.

All thanks so much for all your input, I just want to get back on the road again.

Scott

 

[Jack]

ie rear end fluid change, u-joints and grease the wheel bearings. Those should all be fairly easy task. Scott

Scott:
Those are easy ... except greasing vette REAR wheel bearings. Vettes are quite unlike anything else (IRS)... REAR wheel bearings have to be removed (disassemble rear spindle shafts) to grease em ... disassembly & reassembly requires special tooling (have a pro service rear wheel bearings). Conversely, vette FRONT wheel bearings are easy, simple & straight forward to grease/service.
JACK:gap

 

[blasterfdc]

What about a tool I saw in some of the catalogs ie ecklers, that hooks up to the backside of the wheel bearing assy so you can grease them?

 

[Vettehead Mikey]

What about a tool I saw in some of the catalogs ie ecklers, that hooks up to the backside of the wheel bearing assy so you can grease them?

That's another thing to be added to my 'Bubba's favourites' list. It only greases the inner bearing, not the outer.

 

[blasterfdc]

so are you saying it isn't worth doing, I figured it couldn't hurt and is a lot easier and cheaper if it will help.

 

[Vettehead Mikey]

so are you saying it isn't worth doing, I figured it couldn't hurt and is a lot easier and cheaper if it will help.

Not worth doing. If it 'quiets' a bad bearing, you know it's just a Bubba fix and will need to pull it anyway. Fix it right the first time.

This tool, if abused, can also overfill the beaing cavity and pop the seal out. Then you have grease EVERYWHERE and still need to disassemble to fix properly.

My bet is you need to address your 1) posi lube 2) u joints. If you don't know their service history, best find out now instead of when stranded on a country road at 2 AM.

 

[blasterfdc]

I realize that it is not a fix at all, but isn't it good to grease the bearings anyway. Some of the catalogs state that it is in the service manual of a way to grease them. I was reading another string that said also to be carefull how much grease you do put in. It stated only put in 3 tablespoons.

I am going to address the posi lube (found a supplier for the posi additive) and the u joints. Just thought while the u joints were out it would be good preventative maintenance.

 

[JohnZ]

The GM Posi Additive is available at any Chevy dealer - GM #1052358.

 

[blasterfdc]

Thank you all so much. After a long day at tearing into it. It turned out to be the emergency brake spring came loose and lodged itself in the brake shoe. it was pretty beat up. now I am back on the road again, I guess I will have to order the parts to fix the emergency brake. What a relief. Again thanks to all of your help and guidance.

 

[Bob Chadwick]

I have the part about the posi-lube additive but what oil is everyone using in the differential? I've read 75 - 90 gear oil, 90 weight gear oil and I think I saw reference to a GM part # in one of the posts.

 

[JohnZ]

Any brand-name 75W90 or 80W90 hypoid gear lube will work fine, or the GM Diff Lube (#1052271); I use the GM lube, as I buy it at the same time I buy the GM Posi additive - just convenience. Whatever you use, you still need the GM Posi Additive.

 

[Bob Chadwick]

Thanks John. I got the additive yesterday and didn't even think of the lube.