One thing that has worked well for me is to remove the sharp edge on the leading and trailing edges of the linings before installing the new pads. I used to grind them down at a 45 degree angle on a bench grinder, about 1/8" deep, but that causes a loss of squeegee action after driving through standing water. I've found it is sufficient to rub the edges of the linings on the concrete floor or brush them with a flat file, ... Anything to remove that "fingernail on the blackboard" sharp edge. It seems if you can prevent the squeal from occurring during the break-in period, the lings have less of a tendency to squeal for the rest of their lives.
The flat file should also be run lightly across the piston surfaces and the fingers of the calipers where those items contact the backing plates of the pads. The goal is to insure the pads make full, solid contact and are not held crooked by a tiny spot of rust or dirt buildup. The caliper mounts must be free of rust so the calipers can slide freely back and forth. The mounting contact points should be lubricated with high-temperature brake grease. It is also very important to put grease on the pad backing plates where they contact the calipers and pistons. The pads are going to vibrate. The grease allows them to vibrate freely without transferring the vibration to the calipers where it would become audible.
One of the most important things to watch out for is getting grease, (even fingerprint grease) on the braking surfaces of the rotors and pads. Some picky shops will discard pads that get wheel bearing grease on them, but it is usually acceptable to simply wash all the parts with brake parts cleaner before the final assembly. Once the brakes get hot from normal braking, that grease will soak into the linings AND into the porous cast iron rotors and cause squealing. At that point it can no longer be washed out.
If the car won't creep downhill on its own, or if you can not push it by hand on a flat surface, the brakes are dragging / sticking and will wear out in a hurry. There are a number of things to check for that. The first is to crack open the bleeder screws on the calipers and the steel lines coming out of the master cylinder to see if trapped fluid pressure is the cause of the problem.
Friday, September 10th, 2010 AT 9:01 PM