3 Disc brake warnings

[Bruce Rock]

Just replaced my rotors, pads and hoses. The following problems came up:

1) The rotors were Raybestos RPT and the pads were Powerstop Evolution Plus Ceramic pads. The pads had the following brake-in procedure:

IMPORTANT: BREAK IN NEW BRAKE PADS/ROTORS USING THE PAD BEDDING PROCEDURE AS FOLLOWS. PROPER PAD BEDDING CAN PREVENT ROTOR WARPING.

The break in procedure is critical to brake performance. The reason for a proper break in is to establish an even layer of friction material deposited on the rotors from the brake pads. It is very important that this initial layer of friction material is evenly distributed.

Break in the pads as follows:

5 aggressive decelerations from 40 mph down to 10 mph in rapid succession without letting the brakes cool and do not come to a complete stop. If you're forced to stop, either shift into neutral or give room in front so you can allow the vehicle to roll slightly while waiting for the light. The rotors will be very hot and holding down the brake pedal will allow the pad to create an imprint on the rotor. This is where the judder can originate from.

Then do 5 mod*erate stops from 35 mph to 5 mph in rapid succession without letting the brakes cool. You should expect to smell some resin as the brakes get hot.

After this is complete, drive around for as long as possible without excessively heating the brakes and without coming to a complete stop (Try for about 5 minutes at moderate speed). This is the cooling stage. It allows the heated resin in the brake pads to cool and cure.

After the brakes have cooled to standard operating temperature, you may use the brakes normally.

After doing this procedure I had to drive the last 5 miles home with a dragging brake. The rotor temperature on the passenger side was 107F, while the drivers side was 500+ F.

After letting it sit over night, I took off the wheel thinking I had a stuck caliper. To my surprise, the wheel could be turned by hand. After a short local errand, both rotors were 90F at a ambient of 70F.

I believe having new pads and new rotors does not allow for the expansion that occurs from the energy of the aggressive stops.

NOTE: On-line the procedure has changed slightly. It reads moderate to aggressive.


2) I changed out the brake lines due to the number of members reporting problems with the bracket mounted on the knuckle. I had not noticed any pulling while braking and the rust I could see wasn't bad. I sprayed brake cleaner down the hoses. The cleaner would not run down the hose removed from the passenger side.

3) The lower caliper slide pin has a rubber sleeve. The high temperature wheel bearing grease I used caused it to swell up and bind. Went back with Silicone brake grease.

[Bruce Rock]

CORRECTION: My Wife took the Vue for some local errands. Passengers side rotor was 107F, Drivers side was over 300F. Removed caliper, The lower guide/slide pin could not be moved by hand. Replaced caliper and bracket with rebuilt units from Autozone. The lower guide/slide pin (having the rubber sleeve) was looser than the top one. I had to remove it to satisfy myself that the rubber sleeve was installed. Subsequent trips resulted in both rotors being around 100F.

A stuck caliber may have been the original problem and not thermal expansion

[atikovi]

Originally Posted by Bruce Rock

3) The lower caliper slide pin has a rubber sleeve. The high temperature wheel bearing grease I used caused it to swell up and bind. Went back with Silicone brake grease.

Petroleum based grease is never used on brake parts for that reason and they can run at high temperatures and contaminate pads and shoes. Ceramic based lubes are best for high temperatures. I prefer this stuff: