brake question

[mih0001]

Just recently got a car that had warped rotors on the front. Not a big deal, so I took it to the neighborhood Just Brakes where they replaced the front rotors because they were at the wear limit, got rid of all the old brake fluid replacing it with new fluid, and replaced the pads and mounting hardware.

All that was fine, probably should have done it myself, but i wanted to make sure there wasnt anything else going on. My question is; they strongly recommend having the front calipers rebuilt (for $104) so that the rotors dont start warping again. Would this happen? I've never heard of anything like this, but then again brakes are something I usually leave to the pros.

[Brando]

A caliper having a piston stick may lead to uneven rotor/pad wear. Usually warped rotors come from:

-Prolonged driving with a failed wheel bearing
-Slamming on the brakes at high speed
-Overheating the rotor while using the brakes excessively

As for a sticking piston in your caliper causing your rotors to warp... I'm not sure about that one.

[Dave L]

If it warps the rotors or not it may be worth getting them rebuilt. If they are sticking at the best you will wear through pads. It might be worth a second opinion, especially if its a chain brake place, they may just be looking to ring up the bill

[mih0001]

yeah I suspect its a run up the bill, however if there is some merit to it, i dont mind paying the money

[Razorback1980]

Take a look at Brandon's list of things that warp rotors. In each case you will notice that each one of those items build up heat. A sticking piston will do the same thing as well as eat up your brake pads. Now keep in mind I am NOT saying that your calipers are sticking...that may or may not be true, but heat from any source will warp a rotor whether it's from a bad wheel bearing or excessive brake use at the track or something different. If a piston tends to stick, the pad rubs on the rotor constantly and never backs away causing it to be excessively hot. I would still consider a second opinion. One way to tell would be to drive the car and then take a thermal heat gun and measure the temp of each rotor and see if one is hotter than the other. That will tell you for sure.

[Dave L]

Or simply touch the wheels. I had a bad caliper on the back of my daily driver. the wheel with the sticking caliper was noticeably warmer.

[Lawrence Coppari]

Ditto what Dave L said about the noticeable temperature difference.

Aside:
If it were a rear wheel getting hotter, it could also be a bent stub axle which was my situation several years ago. I thought it was the caliper and got rid of a perfectly good caliper only to have the same problem until I discovered the bent stub axle.

[mih0001]

thanks for all the input, i will do a temperature test today.

[schwank]

Seriously, why rebuild your existing ones when you can buy already rebuilt ones with no core charge for cheaper than the price you posted for a rebuild.

I picked them up from another well known porsche parts supplier in texas for 49 each... and kept my old ones for a future rebuild.

[924Sman]

I have seen more warped rotors due to excessive heat such as track use then the driver applies and holds the brakes and or pulls the emergency brake before allowing the brakes a good cool down first. The car use before you may be the reason but seriously doubt the calipers need changed, assuming they work fine now.

Dal