CBR786

I have a 993 as well as a 964 the problem I have because I have two air cooled cars as well as other daily beaters The P cars get rarely used.

I have ALCON big brake upgrade on the 993 and the other day I was removing brake pads to install new ones and was shocked to to see that the brake caliper pistons which are 6 pots had rusted and some of them have seized.

On speaking to a brake specialist I was told that lack of use and no servicing of the calipers will result in eventual failure of any brake caliper as the brake dust is corrosive. I have yet to pull my 964 from its sleep and look at the brakes on that car. Both P cars are stored indoors with a dehumidifier running constantly.

What I wanted to know is has anyone else come across brake caliper pistons that are rusted so bad that they might need new pistons ?
some people wash cars and dry bodywork and put car back in garage with wet brakes which might lead to rust.

cjoenck

It happens but not after one winter is storage. I am using OEM pistons and calipers and have no issues after many years of summer use only in Illinois.
I think you got some bad material and possibly cheap and fake imports.
Just my 2 cents.

Rocket Rob

I too have had good luck with stock parts. How often have you been changing your brake fluid? Over time, it absorbs water. I change mine every 2 years.

cobalt

I just recently worked on an SC that had all of its calipers and MC rusted solid. The car sat without use for over 10 years. It wasn't worth rebuilding so all components needed to be replaced. This was back in the day of cast iron calipers. Aluminum calipers used on these cars shouldn't have as much of an issue. Although a rule of thumb is at a minimum flush your brake fluid at least every two years and once a year minimum if you track it. I would also consider changing all of your fluids at least every two years if you use the car or not.

porsche mania

Another tip for long term storage is to push that pistons back into the caliper on all four corners. They won't corrode under the seal. Just remember to pump them back up before driving off the next time you use the car. You may need to remove some fluid from the mc to be able to push all the pistons back without over flowing.
Some of my cars have sat for extended periods without having the issues you have though. I always make sure mine have had a a wheel off wash and a thorough dry before putting them away. If you drive in winter then your better off just using the car all the time. There is no cure for salt and crap on a car that is then put away in a nice warm garage, it will corrode less if you just use it all the time.