Brake booster problem?

R

ren_loves_jea

Guest
I've been having a hissing noise from my brake master cylinder area after I shut down my engine. The noise dies out after about 10 seconds or so.

I followed the brake booster testing instructions in the Helms, and I passed the functionality test, where if I hold the brake when the engine is off, then start the engine, the brake pedal would sink. But I failed the leak test, where I would hold down the pedal and shut down the engine, the pedal is supposed to stay down, but mine comes back up.

What can I do? Replace the whole booster? Is there some way to repair it? I did replace my master cylinder a couple thousand miles ago. Could it be that there's some gasket or seal that I'm missing? My brakes feel completely normal, no loss in fluid at all. Any suggestions? Thanks.
 
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