1978 Squeak in Rear

[78pacecargirl]

I took my car to my mechanic because of an annoying squeak. It's audible while driving and is consistent with the rate of speed. Like a metronome, the faster I drive, the faster the squeak. When I apply the brakes the squeaking stops. In 2007 I had new brake lines, hoses and calipers installed to address chatter when I turned a corner. Turned out that problem was just old differential fluid. A costly repair that shouldn't have been. They did, however, find a broken clip that held in the axle, so that was replaced as well as the trailing arm bushings.

My mechanic remove the wheel and put the car in gear so I could see a slight wobble of the whole assembly, and hear the squeak of course. The pads are fine. It was closing time so he said he would work on it Monday. Please help me to understand what the problem could be. Warped rotors come to mind. These rotors are riveted and have never been removed/resurfaced to my knowlege. The wobble is present on both sides. Am I in for a large repair bill?

Thanks for any info you can provide. :confused

 

[bill81vette]

Check your u-joints,you might have a bad one or they may just need grease.

Sent from my DROID RAZR using Tapatalk 2

 

[AussieCorvetteNut]

Sounds like a bearing problem

Just a hunch, it sounds like the bearing is worn in the trailing arm assembly that holds stub axle.
If the bearing is dry, it can cause noise and get louder depending on speed, but could go away when it changes geometry when you brake.
I am only looking at this path as you said that your mechanic has already checked the runout /movement in the assembly.

Trailing arm work is time consuming if you don't have exchange units ready to pop back in.
They will have to remove the arms to press the bearings in.
A great opportunity to check all the U joints.

If the rotors were warped, your brake peddle would pulsate when you apply the brakes. If there was also too much rotor runout (warped discs) you would also get brake fade. C3 Corvettes can pump air into the brake system as the rotor runout acts like an air pump and pumps air back past the seals. If it were warped discs, there would be some other issues, so I doubt this is the case.

Hope this helps.

 

[Vettehead Mikey]

A C3 or C2 Corvette should never be operated in gear with the rear wheels just dangling- more often than not the u-joints at the ends of the half shafts will bind and cause the wheels to hop or wobble- exactly what you're seeing. Your mechanic should know this already.

The key to your problem is 'When I apply the brakes the squeaking stops' which indicates brake pad squeal on the surface of the rotor. Very common, especially when aftermarket o-ring calipers have been fitted rather than the factory chevron type seal. Have your garage remove the pads and look for glazing or embedded chips, stones etc. Have them deglaze the surface of the rotor with a 3M pad and give things a try. If there's still a squeak, there's several kits on the market to shim the pads and damp the vibration.

Given that this is not rocket science for a competent corner garage, I hop this is not the same place that misdiagnosed the differential fluid issue?

 

[Hib Halverson]

My gut feeling is that this squeak is either:

1) Faulty universal joint in the axle shaft on the side which squeaks
2) Faulty wheel bearing on the side which squeaks
3) Mechanical interferrance, such as a brake backing shield in contact with a rotor

If I had to pick, considering the age of the vehicle, that there is visible wobbling and that the squeak stops when the brake are applied, I'll bet on #2.

If you have one bad rear bearing, considering the age of the car, do both sides.

Setting up rear bearings is not easy. Not all repair shops will have the skill or proper equipment. Unless the mechanic who works on the vehicle has experience with C2/3 rear bearing work, I'd recommend purchasing "rebuilt" trailing arms. Zip Products, a CAC sponsor, sells them.

 

[78pacecargirl]

Distorted Hub

Thanks for the info, guys! Today my mechanic removed the brake caliper and rotor. When he manually turned the hub, the gap was not consistent all the way around. Note gap at top is larger:

I have no idea how this could've happened. The vehicle was never in a collision. Could the warpage be due to excessive heat? In any event, can I purchase a hub assembly that would include the bearings? What is a good source? I did not see anything from Zip. Also, I know it's best to repair both sides of a vehicle but in this case is it necessary? Thanks again.

 

[AussieCorvetteNut]

The trailing arm bearing is shot.

I have no idea how this could've happened. The vehicle was never in a collision. Could the warpage be due to excessive heat? In any event, can I purchase a hub assembly that would include the bearings? What is a good source? I did not see anything from Zip. Also, I know it's best to repair both sides of a vehicle but in this case is it necessary? Thanks again.

The bearing is shot. It would have started with lack of lubricant, then grit past the seals, heat and age would have done the rest.

Check with some of the other guys on the forum as to where you can get pre-assembled trailing arms there may be some others (you know local insider info), maybe Ecklers, Mid America, Corvette Central...have used all these guys and they ship to Australia with no problems.

Might want to also check all the U Joints and seals.
While the mechanic is there, check the width of the rear rotors, so you know if you need to replace them next brake reline. The reason they are riveted, is to stop movement and to eliminate rotor runout (what I was going on about before with brake fade).

This is nothing unusual for a Vette with age, but can be time consuming and expensive.

Godd Luck




Tony

 

[i10fwy]

My Guess is the Carrier Bearings

i10fwy

 

[Hib Halverson]

If the gap is larger at the top and that does not move as you rotate the axle, the problem is either with the bearing or the trailing arm.

If the larger gap rotates with the hub, then the axle is bent.

Either way, you're looking at at least removal of that one arm and replacement of the axle or the bearing.

 

[Vettehead Mikey]

If the gap is larger at the top and that does not move as you rotate the axle, the problem is either with the bearing or the trailing arm.

If the larger gap rotates with the hub, then the axle is bent.

Either way, you're looking at at least removal of that one arm and replacement of the axle or the bearing.

Exactly. Find out first before doing anything else.

The reason they are riveted, is to stop movement and to eliminate rotor runout (what I was going on about before with brake fade).

The rivets do not prevent or control runout. The hubs and rotors were riveted at the factory for convenience of final machining and shipping.

 

[78pacecargirl]

This is like learning a new language. Now I realize that hub/spindle/stub axle mean the same part. It's possible someone tried to hammer off the rotor at one time and bent the hub. Who knows? We're going to replace the hub and bearings and see if that solves the problem. I about had a heart attack at the trailing arm assy price - $949!!!

 

[Vettehead Mikey]

It's possible someone tried to hammer off the rotor at one time and bent the hub. Who knows?

Actually no. A bent spindle to the degree shown (irrespective of the cause) would also cause the rear wheel to wobble so badly that the car would be undriveable.

I about had a heart attack at the trailing arm assy price - $949!!!

And so you should. :ugh

Vette Brakes and Products | 1965-82 Left Hand Stock T.A. w/Rebult Bearing Assembly | Bearing, Wrebult, Hand

$399.

or for $329

Vette Brakes and Products | 1963-82 Left Hand Wheel Bearing Assembly | Wheel, Core, Units

if you want to exchange just the bearing and spindle assembly.

BTW- please re-read Hib's post and find out now whether it's a bent hub/spindle/stub axle or simply a bad bearing. It'll make about a $200 difference in the repair bill in your favour.

 

[jimbil208]

Making a noise when driving and the noise stops when the brake is applied is

what the indicator on the brake pad does when it is warn to low.

jimbil208