Washing Car causes Brake Pedal Pulsing?

I washed the car on Sunday afternoon, then put it away in the garage. This morning, I went out and noticed a film of rust on the rotors. No big deal, right? I've seen that before. Well, when I went to drive off, the brakes seemed to "stick" a bit. That is, it took just a bit of extra throttle to get the car rolling, as if the brakes were rusted in place, and I need to apply some force to free them. I drive a few hundred yards, and when I apply the brake, there is some definite pulsation to the brake pedal. What happened? A quick visual inspection of the calipers and rotors revealed nothing obvious. Any thoughts on what to check first?

This happens to me if I don't drive the car right away after washing. Sometimes they stick pretty good and you can hear them kind of pop loose when I back out of the driveway. Do a few high speed braking runs and it should clean them off.

Normal after wash and put away wet. High speed braking will clean them out 80mph to-0 X 3

Quotes source post: 9831387

Yes, check when your local Porsche dealer service department can skim the rotors. Sorry, but things went downhill when you parked the car after the wash with the brakes wet. The pads rusted to the rotors. Apparently bad enough that the coefficient of friction at various places around the rotor(s) is different. In some cases use of the brakes without bringing the car to a halt can remove this rust with no aftereffects. But that you feel pulsing suggests very strongly to me it is too late for your car's brakes. This happened to my VW Golf and I tried a brake bed in operation which didn't help. I do not recall when it happened but the car was still under its 50K mile warranty and the dealer refused to resurface the brake rotors and I was too cheap to spend the money to have the rotors resurfaced, so I lived with the behavior for some time. Fortunately the pulsing was just noticeable during light braking and since I tend to avoid light braking (accelerates brake wear) this was not a hardship for me. The brakes still pulsed lightly when I sold the car with over 120K miles. (I might add the buyer, a woman, during the test drive noticed the pulsing right away... she was a light braker.) Sincerely, Macster.

I always drive the car after a wash, to put heat in the pads to dry them. I try to never let water touch the race pads, unless it's racing in the rain.

I ended up going through a series of progressively harder stops to "re-seat" the pads. This seems to have worked fine. The pulsing is gone and braking is normal. I usually drive the car a bit after washing, but was out of time on this particular Sunday. I'll be sure to squeeze in a quick drive next time.

Quotes source post: 9833027

That's good news. Just remember to *always* drive the car after a wash to dry the brakes. If the brakes are rusty from sitting exposed to rain when you first get in the car use the brakes enough to remove the rust but avoid bringing the car to a complete stop to avoid the risk of some kind of uneven material deposition causing that old pulsing that another brake bed in won't cure. Sincerely, Macster.

When doing emergency stops to fix this or bedding/breaking in the brakes, never come to a full stop. Get to about 5mph and then let off the brakes. Going to a full stop stop can cause the rotors to warp.

Im sure you found out after a mile or two it turned out ok.... what did you do? shut the car off at the end of the driveway and run in and post this post?

the brakes need to be dried off. so take it for a spin. after all, it is nice and clean after the wash.

Quotes source post: 9835930

Actually, I drove it all the way to work, then put up this thread. It's a short drive, on back roads, and I don't usually do too much braking. When I got to work, there was still some pulsation. On the way home, I did a number of progressively more aggressive stops, and that seemed to clear things up.

Quite simply- 996 brakes suck and are "lemon" quality. Oh but they look nice, except for the pitting on the rotors you can never get rid of (pointed out to me by mazda driver in autozone's lot). Long story short- I paid $90k new for my '99 cab. Literally the first time I washed it, the next morning I get the brake pulsation and mechanics start telling me the rotors are warped. I gave up when my parking spot near a stream with alot of fog proved to do the exact same thing (new pitting and new pulsation each morning). Now, I'm getting the sticky pedal thing, and I'm told it's probably from rust in the booster from water getting in. And yes now every time it rains I see that the drains are partially clogged. But what really gets me is => the booster (and ultimately the engine) is at the mercy of these amateuish drains that you can't easily clean out. Compressed air? Come on, I've seen the convoluted route diagram of that tube, which was clearly an afterthought. And insult to injury- there's no attempt to keep water away from those drains, no seals around the cowl. A couple inches of rain multiplies up to a couple feet of water funneled into those drains. Reliability problem. Now headed over to the cab forum to describe how the cab top was DOA upon delivery (brand new) and then how the "emergency" operation does not work, if anyone wants to follow me. Oh but it looks nice (the hidden cab top), if you can get it down.