macinslaw

How can I tell where my issue lies on my brakes?

Here's the deal:

when you pump the brakes, engine off, the brakes build pressure and hold it.

When you hold the brake pedal and start the car, the pressure fades. When I pump the brakes when engine is on, pressure builds slowly, but soon fades if held.

I do not know what DOT fluid is in it, just bought it. checked brake pads, good meat. I'm thinking that the master cylinder is not air tight, please advise. I am not loosing brake fluid.

Scott

p4nc7

iTrader: (1)

Seems one of the seals might be leaking. did you check the area under the brake master cylinder/booster? There's a framerail if you look down, and if pain is cominf off due to an oily residue, then you're leaking. I'd advise getting a new unit.

macinslaw

Really? I had no idea! Can you give me a little better direction as to the location? And this would mean a leak from exactly what, the booster? Master cylinder? Or between them?

Thing is, I don't seem to be loosing vacuum or fluid.

jr426

With power assist brakes, If you pump the brakes with the engine not running you lose assist and the pedel will get harder to push.
If you start the car with your foot on the brake you will gain assist and the pedel will get easer to push.
If you pump the brakes fast enough the engine might not make enough vacuum to maintain assist.
This is all normal, if you have air in the lines you should be able to pump up the brakes and not fade down untill the pedel is released, and a bad master cyl will fade kinda like a brake fluid leak would.
The master cyl can leak internaly so it can be bad even though it's not leaking fluid.