Cadillac Catera and Cimarron Forum Discussion, Just did the rear brakes in Past Cadillac Vehicle Discussion; My Cataer needed rear brakes since I got it 2 weeks ago. The rear passenger side was grinding quite badly.
My Cataer needed rear brakes since I got it 2 weeks ago. The rear passenger side was grinding quite badly.
I got 2 rotors and a set of rear pads ($60 for everything) and started the job. It's amazing how things were rusted. The problem was that the inner pad was not moving when the brake pedal was pressed as the pad was either rusted in or jammed in. The inner rotor surface was totally rusted showing that there wasn't any contact between the rotor and the pad.
The other side was the same thing. I used my Dremel tool to clean out in and around the area where the pads sit. It's amazing how well the car brakes now.
Anyone else have problems with the pads being stuck? Is this a common problem?
No, excessive run out is caused by uneven wear. It is easy to mistake this as "warpage", but that is not the case. Brake rotors are cast iron, cast iron does not warp.
Exactly how hot would a rotor have to become to "warp"? In racing applications, rotors become so hot, that they glow red when applied, and this happens repeatedly, for hours on end. They don't warp under those conditions, and they're certainly not going to warp on a street driven vehicle.
In racing applications, rotors become so hot, that they glow red when applied, and this happens repeatedly, for hours on end. They don't warp under those conditions, and they're certainly not going to warp on a street driven vehicle.
Brakes for racing applications are either carbon ceramic (where heat is of no concern), or heavily slotted/vented discs. Reading on the internet does bring up some articles of discs not warping, it's just pad material being applied to the rotor unevenly, but this is on new/newer rotors, not rotors that have lived a good life.
Steel/cast iron does indeed warp. It's usually when the metal is very hot and the metal is sprayed with water, causing uneven heat dissipation and the metal warps. Have you ever seen a pot on the stove that rocks from side to side, not sitting evenly on the flat surface? This is warped metal, and my old cast iron skillet that I have had for 30 years is proof of this.
Brake rotors are vented and slotted to allow even cooling of the rotor to prevent warping. I have had many vehicles that have had warped rotors. I take a new rotor and place it face to face with the old one and they do not sit flat against one another.
People say "run out" but this is just a fancy term for warpage, no matter how the disc was warped.
Not all race vehicles use exotic rotor material. Cross drilling is more for weight reduction than heat dissipation, and slotting is for degassing. Regardless, iron rotors can still get RED HOT, then cool, over and over, and not warp. Most rotors have a different metallurgy, and are a bit thicker than your old pan.
If rotors warped so easily when "hot and sprayed with water", then everyone who slowed down after coming off a highway off ramp in the rain, would need a 4 wheel brake job.
Call any rotor manufacturer, and ask them about "warpage". Ask about cross drilling and slotting as well.