74 LS4-454

Spoke to my Corvette buddy John (GoVetteGo) about a complication that I am having with my RR wheel and possibly the brake caliper on my 82 "dd".
I replaced the TA's on both sides a few weeks ago, did a make shift alignment until Tuesday, new tires are getting mounted today.
I noticed recently that sometimes taking off from a stop that there is a ratcheting loud clicking noise coming from the RR wheel, and will continue unless I apply pressure to the brake pedal, and then the noise will stop. Sometimes when at a complete stop and then making a hard right hand turn, the noise will start up again, and diminish when the brake pedal is applied. Sometimes hitting a bump in the road will produce the noise at a different level.
John determined that since when you apply the brakes, it appears to be brake related. He mentioned a possibility of rotor runout. And I agree with him. He is even letting me try two different brake calipers to see if the problem gets corrected. Also I will use a dial indicator to check runout.
The purpose of this thread is let you look at the pics and give your opinions about how the brake pads sit in the calipers, comparing the outer and inner pads in relation to how far the pistons are extending from their bores.
If you will notice, both RR & LR pics 1-4 show the inner pad resting right against the inner caliper wall, whereas the outer pad shows distance between the caliper wall and the pad. Both sides showing unequal distance between the two.
On the other hand, pics 5-6 show the two front calipers to have equal distance from the caliper walls with equal amount of the pistons showing in relation to the brake pads.
Not having the knowledge on the correct operation of the actual working of the pistons to the pads other than when applying pressure to the brake pedal that they push the piston against the pad to stop, should they be in equal amounts on both sides in the rear brakes?
Also the rear calipers are part's store replacement, the LR from Advance Auto last year, and the RR from AutoZone just recently.
Again thanking John for his expertise as usual, and for anyone who offers an opinion, much appreciated..................Tom

pic #1....RR caliper


pic #2....another view RR caliper


pic #3....LR caliper


pic #4....another view LR caliper


pic #5...RF caliper


pic #6....LF caliper

Tampa Jerry

I would check the parking brake. The springs can dislodge and the shoes or hardware can rub the inside of the calipers on the rear brakes. Jerry

74 LS4-454

When I installed the TA's, I adjusted the parking brakes shoes loose, (maybe to loose) with minimal drag against the rotor. I have the cable hooked up, but it is stretched and has to be replaced. So the parking brake is non-operational. And applying the brakes shouldn't have any effect on the parking brake shoes, unless as you mentioned the springs dislodged. It almost sounds like when we use to put baseball cards on our bike wheel spokes, but of course a more metal clicking sound................Tom

74 LS4-454

Have had the 82 on jackstands while I took my new tires to the "Boys " to get mounted. Picked up the tires and noticed quite a bit of stick on weights on the inside of the wheel(s). No biggie, NTB did the same a few years ago when I purchased tires from them. It appears these factory aluminum wheels that I have need a lot of weight to straighten them out. BTW, never had a tire vibrate or feel out of balance in the last 65,000 miles that I have put on the 82.
So I put the wheels back on and purposely put the tires with the most weights on the rear of the vehicle. Well as soon as I went forward there was and is clicking from both rear wheels, and now it doesn't stop when the brakes are applied. I am almost certain that the stick on weights (since they are two deep in some places) are making contact with the top of the brake caliper, hence the constant clicking from both wheels. So I imagine I could get out the dremel and shave the top of the weights just enough to give me clearance, or just use sand paper and not effect the balance of the wheels.
Also figured out why my rear pads were positioned like they were in the above pics. Apparently the rotor was not flush against the hub, because the wheel was off. When I held the rotor flush and moved the brake pads, they then appeared to even out.
So a slight adjustment on the stick on weights and I should be good.
It's always something, ....but the new tires feel great, can't wait to get it aligned and back to "dd" status.........Tom

Gordonm

If your weights are hitting the calipers you should be able to see it quite easily when you remove the wheels. There will be shaved wheel weights and you should be able to see evidence of rubbing if they are indeed rubbing. Rotor runout should always be checked. I do this on all brake issues and caliper replacement.

74 LS4-454

I will be the first to admit that I haven't used a dial indicator before, need to learn how to set it up to get a correct reading. I imagine you-tube should have a video on the proper procedure.
My unscientific method that I used was attach 5 lug nuts to the rotor (minus the dial indicator) and turn and pull on the rotor.
Of course that does not take into consideration if the rotor is indeed out of round.
Its just that it seemed odd that when I put the wheels back on, the clicking noise was more intense from both wheels rather than just the right rear. Won't be using the 82 this week as it a short week for me. So it will give me time to correct the issues at hand and learn how to check rotor runout.
I do think and hoping that it is the wheel weights, as there is not a lot of clearance between the caliper and the wheel for one strip of stick-on weights let alone one strip on top of another. If that is the case, was also thinking of lightly tapping on them so they compress enough to give me more clearance.
Thanks for the reply Gordon, appreciated......... Tom

74 LS4-454

Took the rear wheels off this afternoon and sure enough you could see where the wheel weights were starting to get shaved as Gordon mentioned. Call Pepboys, no problem, bring them over. Drove over, saw the tech that did the balancing last week, explained the situation to him, he dropped what he was doing and rebalanced both wheels in 5 minutes. Used the old style weights on the inside of the rim, and left on the stick ons that were not effected. Perfect balance as reading came up 00 00 for both wheels. Fast service I was happy....

Came hone put the wheels back on, and went for a ride. No more clicking like last week, but am still getting a clunk combination click sound when I accelerate quickly, and it seems only to be coming from the right side. Stab the brakes and the noises fades away or stops. Accelerate quickly and does the same thing. When up to speed, no noise. Also went to the school parking lot and drove around in circles both left and right hand at a very low speed to hear anything unusual. Even had the door open with me hanging out Nothing unusual that I could determine, other than some minor squeaks and they could be coming from the poly bushings in the strut rods.
But the way when this noise does happen, there isn't or appears not to be any shaking or vibrations coming from the suspension. so something may be rubbing somewhere.... Hope its not any u-joints or anything in the rear....
Going to the dealer Monday for my alignment and will let the tech check out the noise. And the new tires feel great even without the alignment very responsive going back and forth from left to right, and right to left at a decent speed. These new Radial TA's feel way better than the old ones I took off. So we shall see what Monday morning brings........

74 LS4-454

Got the 82 aligned yesterday, see the results in my alignment thread.
Driving to and from work yesterday, raining all the way, the squeaking from the rear suspension appears to be non-existent. So there are some parts that apparently needed some type of lube to quiet them down. Will have to see how they react when everything dries out.
The louder click-clunking sound also has seemed to diminish, hardly heard anything from the right side rear. Can only think that since that wheel was out of spec for the alignment, could it be possible that the halfshaft was torqued in such a way causing undo pressure on the u-joint, therefore creating the noise I was hearing???? And now that the 82 is aligned, everything is where it should be and operating correctly. I'm not sure on my own question, but will have to complete more rides to work to determine if my theory makes any sense.
All-in-all, running and riding great and for 132,000 miles, that's not to bad at all!!!