Mr Fufu

I'm wanting a heads up on the following issue with my '67 coupe.

Whenever I apply the brakes I get a loud high pitched "screeching" sound. This only happens for a short time, just as I apply the brakes. As soon as the pads 'bite' into the rotors, the noise disappears. The car stops straight, there is no fluid leaking, and otherwise the brakes appear to work just fine. However, this initial high-pitched noise has been getting louder and more obnoxious over time, and I want to finally get rid of it.

So, I took my car to a shop knowledgeable about Corvettes yesterday. They took apart the brakes and confirmed that the calipers and rotors are fine. The calipers were replaced with SS sleeved ones about 10 years ago, by the previous owner. The shop diagnosed the squeaking to be caused by the organic brake pads on the car. They suggest I switch out those organic pads for semi-metallic composition pads. In addition to the pad switch, I'm told they'll have to reface the rotors to remove the glaze deposited on them from the organic pads.

So far so good. Now to the cost. I'm told I'd need new brake pads all around, and about 3 to 4 hours labor to switch the pads, turn the rotors and put everything back together again.

My questions for you are:

1. Do you agree with the diagnosis? Have any of you had this screetching noise on brake application issue from using organic composition brake pads?
   
2. What should I be paying for new semi-metallic brake pads? I'm in Canada, so realize the cost to me will be at least 30% higher than for you good folks in the USA thanks to our weak dollar.
   
3. Should I look to replace only the brake pad set that is squeaking? Or should I be doing all 4 corners (i.e. new pads and turned rotors) at once?
   
4. Is the estimate of 3-4 hours labor realistic for replacing all pads on all four wheels, including turning the rotors too?

Any tips/feedback are much appreciated.

Cheers,

Alex

Bluestripe67

Did you feel that funny movement in your pants pocket? It was the hand of the shop trying to find your money. I made the same mistake several years ago of putting performance pads on my car. Screeching etc was the result. Removed them, bought basic pads from Paragon and went down the road and never heard a sound after that. Replace all the pads! No need to turn rotors etc. Dennis

ILBMF

I would also go with new stock pads from Paragon or Lonestar. Wouldn't hurt to scuff the rotors by hand with some 80 grit before the new pads go on.

R66

I have never had organic pads squeal unless they were worn out and the metal backing on the pad was dragging the rotor. But, I have not experienced everything in my life time.

On a lift, I would not expect pad and rotor change out to take no more than 10 minutes per wheel tops (with air tools). Turn the rotors, maybe 10 minutes each very max. to grind.

But, don't forget you have to pay for the down time of the mechanics between jobs and the overhead of the management and facilities as well as the country club membership, bar bills and etc.

I would not mix organic and metallic pads on the front or rear, but at least the 67 has a dual master cylinder.

Then again, in the great capitalistic country of America (formally a democracy) the economy brake job for four wheels would cost you between $800 and $1500.

Nowhere Man

you forgot to say if the last shop who did the brake work riveted the rotors like factory.

63split63

If you take your car to a professional shop they are not likely to do a budget job on brakes or suspension . I would never do brake pads without replacing or re surfacing the rotors , checking all hoses , lines and master cyl for leaks and rust and a road test when complete .
If you do it your self you can cut corners .

Bill

ILBMF

A lot of shops now have the equipment to turn the rotor right on the car, but if you only have that initial squeal I would try new factory style pads right from a reputable vender and scuff the rotors with the 80 grit emery cloth or sand paper.

Edit: if the rotors are smooth and not grooved at all on hand scuffing

Powershift

If I recall, there are "anti-squeel" pads/insulators that you buy to adhere to the back of the brake pads. I have them on my own car.

If you change pads, use the regular type from the sources mentioned earlier (Paragon, Lone Star, CSSB Inc, etc).

Don't let anyone turn the rotors unless they REALLY know what they are doing and then make sure they perform run-out checks on the rotors afterwards to ensure that it is within the Corvette specs. Otherwise a recipe for problems. If needed, hand sand with #80-100 grit paper and a sanding block to break any glaze. Don't cut the rotors unless they are badly grooved...........and then only if you know what you are doing.

Probably a good time to also flush out any old brake fluid, especially if DOT 3/4.

Larry

GTOguy

As an auto technician, the quote you received is pretty much spot-on. Be advised that squeaking is usually caused by glazed pads and rotors, and can come back if the conditions are right. It's all harmonics, like you get when you run your finger around the rim of a crystal wine glass. A quick and dirty way to fix it, at least temporarily, is to scuff up the rotors, with some every cloth or even to take a brake lathe bit and scratch some grooves across the rotor. To break up the glass-smooth surface. Old drum brakes sometimes have a spring wrapped around them to dampen vibrations and stop the same noise.

Bluestripe67

ILBMF amd Powershift are thinking with common sense on this. Dennis

MikeM

Be me, I probably wouldn't touch the brakes until I got ready to stop and then "use" them. Thereby, eliminating the squeak/squeal.

When doing brakes on disc brake cars, I've never had the rotors turned, even if they had some scoring less than 1/3 across the face of the rotor. I don't believe turning them is necessary as the pads will very quickly wear in in just a few stops.

I commercial shop can't afford to do this for obvious reasons. I recall one time I replaced pads on disc brakes and got a squeal. I put some of that dope on the back side of that pad and that fixed it.

I've even re-used brake fluid soaked Corvette pads with no problem. Straight, quiet stops.

Don't do what I do. Just relaying another way to do things.

I never ceases to amaze me what people spend on maintenance through commercial locations.

BD104X

I'm confused by the logic on the pad material- usually semi-metallic pads last longer and are more aggressive than organic but the biggest downside is that they are more prone to noise. I also feel that to do a brake job properly you need to turn the rotors, and in my experience cutting that corner leads to noise. If you were just changing pads on a very gently used car, I could see not turning them, but being as you are chasing a noise issue I think it would be foolish to skip that step. The 3-4 hour labor estimate seems high to me, but If the shop is using an on-the-car style lathe to turn the rotors, they can be time consuming to set up, but I've also heard from several people who own classics that they feel like they get taken advantage of by the shops willing to work on them. Maybe time for a second opinion from a recommended shop.

Frankie the Fink

I redid EVERYTHING on my '63 original drum brakes except the hard lines and turning the drums (they didn't need it) for under $300 worth of NAPA parts and a Saturday morning's work and disc brakes are easier IMO. I would think 3-4 hours labor would be at the extreme upper end for the job by a "knowledgeable" Corvette shop...

phil2302

Exactly right ^^
Why fix what isnt broken.
Make sure all lines, hoses, fittings, M/C do not leak.
In the absence of any pulse, shake or vibration when pressing the brake pedal the rotors are most likely just fine.
If there is a shake or pulse the rotors will need to be cut (if there is enough metal to still do this) or replaced.
All 4 wheels of my 66 have the original riveted rotors. I changed the calipers once in 1986 and the pads twice in the last 30 years but the 50 year old rotors remain.
Change the pads and rub the glaze off the rotors like others have already suggested and it should be fine.
Choose which ones you like but I prefer organic pads vs the semi metalic. I think the metalic pads will wear the rotors faster.

Mr Fufu

Thanks everyone for sharing your experience and views on my brake squeal problem.

As mentioned, the car stops straight and true, with no vibration. The only annoying issue is that momentary break squeal which happens each time I apply the brakes. I only put about 1,500 miles a year on the car, so it is lightly driven. I've been putting up with that damn squeal for about two years now and it needs to be fixed.

The shop where my car is being serviced has a good reputation and has been in business over 35 years. They specialize in Corvettes and older American cars, so I know they are capable. However, its also true that they charge more than some shops. I'm willing to pay a bit more to ensure a proper job is done right the first time.

I'm heading out to the shop today to see how they are getting on with my car, and to get a firmer estimate on the repair cost.

Wish me luck.

Mikado463

While probably not an issue (based on what you have told us) be sure they check for runout on the rear rotors. Because of geometry and the fact that they are fixed to the spindles, they can if out of true (no more than .005") create an air pumping issue within the caliper / piston interface (more pronounced with lip seal pistons vs. o-ring style)

Again, probably not an issue based on what you have said but question the shop anyways for if they don't know of this then they ARE NOT as competent as you think.

colo63sw

There is also a poor man’s way to try on this.
Change your driving style for a little while. Do more aggressive stops for a couple of days, this may deglaze the rotors. If you normally brake aggressively then be gentle for a while.
I had a C6 that would have a brake noise (especially on turns) after a hard stop; 50-100 miles of average driving/braking and the noise went away. Happened several times, very repeatable.

Good luck.

MikeM

Millions of rotors are probably needessly turned every year, not because they are warped but simply because there is brake pad residue stuck to the rotor surface. Maybe .0005 thick. Every time the clamped pad passes that spot on the rotor, it will grab and cause a pulsing sensation in the brake pedal.

The brake pad material stuck to the rotor is caused by getting the brake rotors hot and then holding the brake pedal on when stopped and the heat transfers some of the pad to the rotor. You can fix this three ways.

a) quit hammering on the brakes by not using them needlessly and severely

b) you can sand those deposits off the rotors

c) you can get out of the bad habit (a) and drive moderately for awhile and further brake action will eventually clean the rotors

FWIW, I have not seen a midyear Corvette with the problem just described. Not saying it doesn't happen, just haven't seen it.

colo63sw

Seems to confirm my 'poor man' post.

Mr Fufu

Good idea!

I'd rate my driving style as moderate, so perhaps a few days of aggressive stops are in order to see if this helps deglaze the rotors in hopes of quelling the squealing noise.