I had an intermitant clicking in the rear of my 75. It was always at slow speed and was hard enough to feel in the seat of your pants. I was leaning toward the rear end (hoping a fluid change would fix it) and took the car to my local mechanic requesting he pull the rear cover and take a look. He called and told me I deffinately needed rear wheel bearings. (He told me he road-raced vettes in the 60's and had a lot of experience with them.) Both sides were bad, but after getting a price I decided to do the right side only, which was clearly the worse of the two. They installed a rebuilt (i think) trailing arm assembly. There is a tag on the bottom that says "Genuine GM Restoration Part". I picked up the car and all seemed good. Not long after the clicking returned, worse than before. I wasn't surprised, because they told me the left bearing was bad as well. The car sat for about two years like that only being driven about 500 miles. I decided to tackle that job myself when I had more time. This summer it got to the point I couldn't ignore it any longer - you could hear metal scraping on metal. Well the wife was visiting her parents with the kids for the past two weeks so I ordered a rebuilt trailing arm from ZIP's and installed it (PITA). I took the car to a new goodwrench service center (nice guys) for an alignment afterward and the clicking is STILL :U there. When the goodwrench guy calls me he says the right wheel bearings are loose as hell. This is the GM part that was put in by the mechanic. Is there anything else that could allow the spindle to move in and out? The tech said the trialing arm isn't moving and the spindle nut looks tight. What else could it be? Remember, I've only put 500 miles or less on the car since it was installed.
thanks for any help you can give me. :cheers:

 

If you jack the rear wheel off the ground and grab the wheel at 9 and 3 you should be able to feel bearing looseness if it is loose as hell. If you don't feel movement there, grab the wheel at 12 and 6, if you feel movement there, it is probably in the yokes. As for the clicking, I would change the diff fluid and add 2 bottles of gm posi fluid and do some 8's before I did anything else.
bob

 

You did'nt mention u-joints. How are they? They often "click" when going bad.

 

I could shake the wheel at 9 & 3, 6 & 12, 8 & 2, you name it! I put it on jack stands and rotated the wheel by hand, trying to see if the u joints were loose - everything seems tight up to the differential - then I get about an 1/8" of movement each way.
On the rear fluid - I'm having the GM tech do that while he has it today. One idea - if the spindle nut wasn't torqued properly, could that cause the bearing to be loose?
greg :confused:

 

The torque on the bearing nut is 100 ft/lbs. If you have access to a dial indicator you can measure the amount of end play in the bearings. You should have less then .003" for a good fit. Usually they're set to .001". Does the spindle nut have the cotter pin through the slotted nut?
Gary

 

Usually u-joints click a lot and then clunk a little before dying completely, mine clicked at low speed, and then at a higher speed the noise disappeared, probably the clicking drowned out by the noise from the rest of the car. let me ask you this, after your mechanic put the one trailing arm on, did he or someone else do a rear alignment??? at the trailing arm pivot point does the bushing look fairly new, do the alignment shims look shiny or some look newer than others. if not i would say your mechanic pumped some grease into your old bearings and maybe used a little clean up & spray paint on your old trailing arm and then pumped some cash from your wallet.


[Modified by Gary79, 6:17 AM 8/7/2002]

 

Gary;
My family and I have used the shop that did the work for many years. They will sell you everything you need and anything they can talk you into, but in my experience they do the work they charge for and are fairly competent. They let you get under the hoist with them and see what they're doing. The trailing arm they installed has a GM Restoration Part sticker on it, and it has a new dust sheild and rotor. The shock mount is new too, so I'm sure they had as much trouble as me. :smash: The tech at the goodwrench center where I took it yesterday for a rear alignment said it didn't look as nice as the one I just got from Zip's. It also looks like they replaced the right side U joints when they did the arm. (I need to find that repair order). Anyway, when they did the differential service yesterday he said it looked like the original fluid was still in there. They replaced it and put in the additive. I took the long way home and wasn't able to reproduce the clicking. I still have the bad bearings in the right trailing arm though. He wouldn't even do an alignment on it because he said it was so bad there was no point. When I find the work order I'm going to go back to the shop and see if they step up. Next alternative would be to get another (free?) trailing arm assembly from their source and do it myself. The problem is, it's been 2 years and the shop has changed hands since. We'll see.
Greg