I'm not a big fan of "squeak" and "bump" complaints, but here goes anyway...

In typical suburban driving I have noticed a pronounced "growl" when moderately to heavily braking from about 45 or 50 MPH. The growl only becomes audible and felt a bit in the pedal (but mostly audible) at speeds 10 MPH or less and only after a stop from higher speeds.

A lite braking glide-type stop is whisper quiet. Heavy braking from say 50 MPH to 35 MPH is also quiet.

It's only the last bit of heavy stopping that creates the growl.

The front pads have 15,000 on them and the rotors were good then, though I didn't cut them. The rear pads are original (78,000 miles) and had plenty left on them at 63,000 miles.

Alignment is spot on, tires are fresh and there are no steering problems or front end issues.

Transmission has the original fluid, though that's going to change soon. No other issues there.

My first guess would be the rear pads which I'll look at this weekend. ANy other ideas?

Thanks!

 

Hey Spurlee,
My two cents!
Sounds like brake pads. Fronts will always wear more than rears becuase of the bias applied in the braking system. Also, pads rarely wear evenly, one edge, usually the leading one will wear faster. I wouldnt be surprised if when you pull the front pad that one edge will be significantly more worn than the other. If that low edge is really low it may well cause metal to metal contact with the disc as it expands due to heating. Usually when the condition is marginal you only hear it at low vehicle speeds. Dont delay on this, you may need new rotors if this continues, if its light scoring you can have a brake shop resurface the disc. If not even OEM rotors wont break the bank and youll know youre all good.

Good luck, and remember this is one mans opinion based on your post,, not having seen the issue in situ.

Cheers,
Andrew

 

Parts of the disc brakes are moving. The pads 'float' on the rotors within the calipers, and the caliper itself has limited freedom to slide in/out on the rotors. When they become corroded or loose; sometimes parts become stuck or stiff to move, squeak, vibrate, or in your case; groan.

I use a combination of high temp lubricants to insure moving parts are clean and free, and sometimes will apply either shims or paste behind the pads to keep them from vibrating...

Here is a good page to read:Eliminating Disc Brake Noise

 

I also use hi temp paste behind the pad, it works well and is not a common practice anymore. I have never had squealing pads. I also wire brush the points where the pad carriers slide along the caliper and put some anti-sieze there. Hi temp grease on the pins, too and make sure the seals are good and seated correctly.

I think my moving parts in the front are good - I serviced them just 15,000 miles ago or so. I'm going to look at the rears first since they haven't seen service ever. Then I'll look at the fronts again.

Thanks!

 

Well you know most of the tricks on keeping brakes quiet. I bet you'll find something pretty simple when you dismantle the rears. Don't forget the e-brake mechanisms.

Keep us posted.

 

My brakes also growl with a metallic sound when coming to a stop.

That started after the brakes were turned & new pads installed 2 months ago. Since there are no brake low warning sensors, the pads have to be visually inspected, right?

The growl may be from the metal particles in the brake pad?

 

.

 

My guess is your growl is vibration of the new pads. The fix is disc brake paste. Read the earlier post link. gordo