Possible brake issue

[Behold81]

I am wondering if when on boost I'm leaking in to my brake booster. Is there a knew at valve I need to check or insert to insure I am not pumping up my brakes after a thrash?

[mik_ok]

No possible connections I can think of.

What are your symptoms?

[Behold81]

Pedal after a thrash seems hard and can sometimes be a little vibratey (I know that's not a word).

I have heard people mention this on other forums about boost leaking to the brakes.

It's really annoying. The other possibility is a shot master cylinder.

[mik_ok]

Symptoms could be your servo leaking when you're not on the pedal. I had this problem on a Ford Ka once - sprayed in some lube and it was all fixed.

Not sure that can have anything to do with boost from your charger though.... ?

[stevieturbo]

Hook up a pressure gauge as close as possible to the servo.

And do you have a check valve on the vac line from intake to servo ?

When driving, after you shut the engine off, is there vacuum retained in the servo ? ie the pedal should still have assistance for a few pumps.

[Behold81]

So some progress/developments.

The hard pedal is not from lack of vacumm it seems. I say this because if I thrash it from say 30 to 70. Let's say 70 the car starts to judder and the pedal is solid and it feels like the brakes are applying and juddering and only a little travel applies the brakes fully.

If I cruise up to that speed it's fine no issues.

The symptoms takes 1-2 mins to subside.