Boost Leak In Brake Booster

[jmcboost]

So, I've been trying to track down a nasty whistling noise when I boost over 10psi. It was coming from inside the car and I couldn't pinpoint it. I finally found a definite leak coming from the break booster. I can feel the air coming out of the area where the brake pedal meets the firewall.

So my question is, is there a seal that would cause this to happen, or do I need to replace the whole brake booster? I noticed the TSRM shows a seal/gasket that goes in between the firewall and the booster.

Also, as far as I can tell the leak only happens the most when the brake pedal is fully depressed. If I pump the brake pedal, the leak seems to goes away.

Any help would be great!

 

[jmcboost]

Ok, so I just found that there is a check valve on the vac line that goes to the brake booster. Man, I hope that's the problem. I didn't even think about that. :3d_frown:

 

[dumbo]

Yah that check valve is there so the brake booster holds vacum. If its leaking your turbo may have pressurized your booster. Weird though that you feel air coming out at idle. Do your brakes still work good?

 

[jmcboost]

No, I can only feel air when I do a boost leak test. So I'm pumping air into the intake manifold and I can feel the air coming out of the brake pedal area. I did a 2JZGE-t swap and don't have check valve on at all. So I'm pretty sure this is the problem. I didn't know about the check valve until just a minute ago. But it makes complete sense.

Oh, and brakes work great. No problems.

 

[dumbo]

Put the check valve in.