Brake noise--even after new pads (twice)

[UNC036]

Originally Posted By: morris
turn rotors each time. wash with soapy water. sounds to me like you guys took the blue pill. i was a machinist for 25 years, not automotive. aircraft. this deal about turning on the truck is hokum. ill bet i could turn one on and one off, that you couldnt tell the difference. one time i resrfaced a rotor on the car, didnt have a lathe, with a dotco by hand it turned out fine. cars are NOT rocket science.


Hokum Huh???

A Soap and Water Wash after truing a rotor, whether on the car or on the bench lathe prevents the rotor from contaminating the pad.

I'll take that bet... Cause my dial indicator doesn't lie.

Brake rotor run-out has changed since the day of asbestos pads. Asbestos used to be 7 thousands, it is now down to 2 thousands, and with Nissan requiring no more than 1 thousands.

It is not so much eliminating the run-out on the bench lathe, but matching the rotor to the hub assembly's run-out.

Have a look here: http://www.procutinternational.com/index.aspx

Hope it helps, Jim

 

[mrdctaylor]

Just to follow up with everyone...

I found a suggestion on another forum about how to "bed" new brakes. I gave it a try 2 days ago and the squealing/squeaking has not returned! I hope it is gone for good. The advice I followed was this:

- Get the car up to 60mph, brake as hard as possible w/o locking up the wheels down to 20mph.
- Repeat once or twice.
- Go from 20mph up to 60 while slightly holding in the brake.

I did this and I've had no issue. I let the previous set of pads go about 2500 miles and they never stopped making noise. This got it to stop in just a few minutes and so far they are still quiet. Hopefully it will stay that way.

 

[mechtech2]

For normal street brakes, just drive normally.
It may take 50 to 500 miles to seat things in .
It would not hurt to have an aggressive stop here and there.

Race bedding techniques do not apply. Pad deposition to the rotor is way different when racing.

 

[Surestick]

Originally Posted By: mechtech2
For normal street brakes, just drive normally.
It may take 50 to 500 miles to seat things in .
It would not hurt to have an aggressive stop here and there.

Race bedding techniques do not apply. Pad deposition to the rotor is way different when racing.


I've always wondered about the usefulness of bedding in the pads, at least as far as the pad leaving material on the rotor.
The first time the car sits in the rain the rotors are going to develop a coat of rust that must leave behind a "clean" rotor once the pads scrape it off.

 

[doitmyself]

There's tons of brake bed in procedures on the net. I remember Bendix's 30/30/30 one the easiest. Like Mechtech2 said, aggressive is not required on street systems. And, improper bed in can mess things up.

I disagree with Morris that you need to turn the rotors every time. Many people skip this step and GM even has a TSB recommending not to turn them unless circumstances dictate it.
Per GM TSB:
"Rotors are not to be resurfaced in an attempt to correct the following conditions:

- Noise/squeal

- Cosmetic corrosion

- Routine pad replacement

- Discoloration/hard spots"

TO THE OP....Good luck on your fix! Hope it works.

 

[RH+G]

Im surprised soo many people turn rotors still. I havent turned a rotor in about 10 yrs and never had a problem I think it comes down to the tech doing the job on what they feel comfortable with.

I have seen shops turn rotors that brand new are bout 50 bucks each. I dont see the point in that but to each is own. I dont even buy premiuim rotors anymore cause the standard quality rotors hold up very well. Unless its a car that is hard to change the rotors or tends to warp rotors.

Dealer is another story when doing warranty work. U have to follow their procedure even if u disagree. Cause warranty claims are soo annoying when they reject it and u look like u didnt know what u doing even thou the car has been perfect since u fixed it