chroot

How likely is it to warp your rotors by spraying them with water when washing a car? It's tough to wash my car when they're cool, because I have to drive to the carwash to wash it. I haven't noticed any warp, but when I (accidentally) spray them with water, they hiss and steam. Just wondering if this is something to worry about or not.

- Warren

bayarea408

if you drive your car rough and the rotors are very hot. and then you wash the rotor with cold water. the chances of warping your rotors is very high.

think about it.. HOT THEN COLD so fast, not a good combination.

Wesmaster

Actually, I think the rotors are plenty strong enough to resist warping from splashing water on them. The only real risk to warping rotors is parking with your parking brake on at a track event where the rotors have gotten VERY hot.

chroot

I have to agree with Wesmaster -- I know the parking brake can do a great deal of damage to a set of very very hot rotors -- the part of the rotor under the capiler is kept hot by the pad, and doesn't have the chance to air cool like the rest of the rotor, so the rotor endures a long, painful temperature differential.

However, splashed water evaporates almost instantly off the hot rotor, and doesn't really cool it down much at all -- it's still almost equally hot if you splash it twice. I've washed my car a few times, and had the rotors steaming, before I even considered that it might be bad -- and no damage has occured.

I think driving through standing water with the rotors hot might cause more of a problem -- but there are many other more pressing reasons to avoid standing water.

- Warren

Wesmaster

So you're answering your own question?

Mike Schuster

Actually, it is not hard to warp the Honda rotors. If you come into the pits after a hot lap for space due to traffic, or to switch passengers, you have a good chance of warping the rotors, burning the rubber brake piston seals and even melting the rubber air filler stems on the rims. I did this all yesterday and am having repair work done tomorrow. Give them time to cool down a bit first.

Mikey

I know of quite a few S2K's that have driven on the track in the rain. The brakes were super hot and constantly soaked in water, yet they didn't warp.

Warping generally occurs due to either:

very worn rotors
aftermarket track pads and heavy braking (track days, etc)
improper lug nut torque.

meat

Mike - you were not along in the hot pits with some hot brakes yesterday. Many people came in to swap passengers/gain spacing/etc and their wheel wells looked like someone had a campfire going in them!

chroot

Mike -- sorry to hear about your brake damage -- I guess all those instructors-only "pickup-and-switch" sessions are actually bad news. I'm guessing it's a huge pain to replace the piston seals. I noticed you had some vibration during your hard braking, and I guess that was due to your rotors.

- Warren

Mike Schuster

Yes, rotors. In the past with reasonable cool off laps I have been able to avoid rotor warps but have not avoided outer dust seal damage. They are just too exposed and replacement is expensive and time consuming. I am going to have the metal splash guards removed tomorrow which may help.