Brake booster filling with fluid, what gives?
 

My brake vacuum assist is filling with fluid and in turn, the engine is ingesting the fluid via the vacuum line.

Now, I am no brake expert, but I know that is not supposed to be happening.

Does this sound familiar to anyone? What's the story?

Also, what's the upgrade path to the GM master cylinder with the 2001 two bolt booster?

One, or maybe both seals, on the pistons in the master are leaking. Fluid is getting past the seal and into the booster, helped along by the vacuum. Fix it sooner rather than later, because if the seal goes completely your going to need holes in the floor to stop Fred Flintstone style.

So you are thinking that it's the MC, *not* the booster?

I am I correct in assuming that fluid should not be escaping the MC via the pushrod under any circumstances? It shouldn't be building up in the well between the two, outside of the MC, right?

Now that I think more about it maybe it is the booster. Fluid definitely should not be coming out of the master at the pushrod, you're correct. But I guess if the front seal on the booster is leaking the vacuum could pull fluid from the master. Whether that means the seals on the master are bad too I don't know.

That's the same place I am stuck... I am not sure which component is the problem and which is the symptom...

Brake booster and the master cylinder should both be inspected. I spoke with my tech here and he said they could both have problems.

Thanks for the info. I was afraid that was the case... they are not cheap, either of them.

:baby:

Please update us with the fix! :D

:guitar:

I am afraid that at this point, the "fix" is just going to be to throw money at the problem and replace both the booster and the master cylinder.

I don't want to spend too many days debugging it.

my vote would be for the mc I've replaced both and I don't think fluid would even make it to the booster if the mc wasn't bad.. I haven't changed one on a toyota but have on a few other (lesser) brand vehicles ;^) so it may be slightly dif. Just my two cent.