I have a SQUEEK in the back---I think!!

[zog]

My 86 coupe just turn 97,000 miles....at almost the same instant it developed a soft, low pitched squeek (like a rubber bushing rubbing on something). I only here it with the windows down, and as I am leaving a parking place, whether going forward or backward. It last for about 2 or 3 tire revolutions and quits. Does not do it again until I park the car....strange, huh??? Any ideas???
I crawled underneath the car, bounced it up and down, and can't find it....

 

[zog]

Surely someone has this kind of problem....please help

 

[vette-dude]

Well, since no one has answered I will venture a WAG. I once had a similiar sound that drove me nuts (well more nuts) and it turned out to be a Ujoint. Bouncing the car up and down did not make it happen but moving slowly fore and aft did. Have you ever changed your ujoints?? look at then and see if there is a rusty looking powder around the caps where they fit onto the trunnion. If so they are bad and you can spank them, send them to their room, or replace them ( your choice). That's my guess. Anyone else??

Randy

 

[jmccloud]

Far left field

U-joints are most likely but consider:

I had a squeek like that in a non-Corvette but a similar cause could apply here.
The squeek was present only during or briefly after a rain. If passengers were in the back seat, it really wailed. Replacing the trailer arms and a lot of other suspension helped NADA. Probably spent >$400.
When replacing the rear disk brake pads as routine maintenance, there it was!
The emergency cable was worn clean where it ran next to the tire. Pulling the very small amount of slack the other side of a bracket to give tire clearance cured the squeek. Evidently the dampness of the rain caused the two clean rubber surfaces to vibrate but when dry they didn't. Next tire replacement the original size is going on rather than the wider, lower profiles now on it.

Or from a more usual source, have you checked the brake pad wear indicators? Sometimes they start to squeel more noticably at low speed.

 

[zog]

Thanks for the reply

Seems like it makes sense that it is the u-joints. I just replaced the brakes, so it can't be the wear indicators....

I also changed the rear end fluid and used the GM posi-stuff, but I opted to use Mobil 1 75-90 gear oil (2 quarts). I had assumed that stuff was pretty good, but could it be the rear end????

 

[Moonunit 451]

I'm down with the U-joints. The original ones on the propeller shafts at least did not have grease fittings on them. I replaced the ones on my passenger side shaft due to squeking at 109,000. If you get the back end off the ground and spin the wheels you should be able to isolate the problem. I got mine up a hoist and it was easy to track down.

 

[zog]

What type of u joints did you buy. I was amazed that Chevy wants $50 each...Parts America only wants $14 each...the GM units do NOT come with grease zerks, but the Parts America ones do have the zerks...I love my Corvette, but GM is a real rip in some cases.....

 

[vette-dude]

ZOG,
You should replace the ujoints with ones that DO NOT have a grease joint. The trunion is cross drilled for the grease channels and with the HP of a Vette they will fail. Just my $.02.

Randy

 

[zog]

That's a god point, and I had not thought of that....do you know of any brand that does not have the zerks, without gooing to GM at $50 a pop??

 

[Moonunit 451]

Can't handle 230 hp? Hmm, vette-dude, not saying you're wrong, but do you have any referance to back up your statement ? I really need to know if this was a bad move on my part

 

[zog]

I have found that many of the companies(ecklers for example) sell the replacement u joints with the zerks. For about a quarter of the cost, that's what I'll go with.....

And, of course, as I removed the u jopints, I noticed that the spring has started to delaminate...another $300...love that Corvette!!

 

[vette-dude]

Moonunit451,

All I can say about the no zerk subject is I left a half of a drive shaft somewhere at the MEMPHIS International dragway that was a result of a driveshaft ujoint failure with a ujoint that had zerks (not a fun ride as car was going 112 mph and it took out the rear end, trans, fuel lines, and brake lines). Replaced it with a Denny's driveshaft and solid joints, added another 100HP to the motor and never had another failure. Maybe a 230HP engine might not need the solid joints but I would rather be sure that if I added some HP I don't break a joint on the half shaft. I have yet to see anyone properly grease a ujoint or maintain them so I don't see the use for a zerk type ujoint assy. The concept is ideal but the actual practice of PM for the joints is lacking. A solid joint, properly lubed when installed should last for over 100,000 miles in normal use so why use a crossed drilled weak ujoint in a High Performance vehicle? Just my $.02.

Randy

 

[Moonunit 451]

Thanks vette-dude. Taht certainly is worh considering. Was that your main or your propeller shaft? How old were the u-joints? Just curious?

 

[vette-dude]

Driveshaft broke. Ujoints were new two passes before they let go. It weren't a pretty sight!!

Randy

 

[Moonunit 451]

Thanks Randy, I'll keep that in mind when I do the others.