Hey Guys,

I am losing brake fluid out of my metering block on my 84 T/A. It's very obviously wet and as far as I can tell, I don't believe that my lines are leaking. However, there is a plastic switch or something that sits on the top of the metering block right in the middle. There is what looks like a wire or maybe very small vacuum line going to it. I cant seem to find a parts store that even knows what it might be called. Might any of you know? Is it something replaceable or am I going to have to go junk yard diving? Thanks!

 

That's the switch that lights your "Brake" warning light when the brakes fail. It's not replaceable separately, only by replacing the combo valve.

More likely, your leak is either the master cyl (very common), or the little plug thing in the end of it. A trip to the car wash will help make it easier to nail down.

 

well, I did clean it up pretty well and it does appear to be leaking right in that switch. I'll clean it up again and see if I can tell ant better this weekend.

 

I haven't been able to get to clean it yet so for now I make sure my brake fluid is always full. Now my brake light is coming on all the time and I know for a fact it's not the E-Brake that's causing it. You menitoned that tha'ts the light for my brakes "failing"...Could that switch be bad? Or could that signify that maybe I have air in my lines somewhere? Where can I get a new combo valve/ from? Is that something I can buy or will I have to go junk yard diving? Thanks!

 

You're continuing to fill your reservoir and your brake light is on. Appears the switch is working fine and is telling you exactly what you already know.

Find the leak and fix it. Leaking at the switch is unlikely but not out of the realm of possibility. First make sure the cover to the reservoir above it is on correctly with rubber gasket seated all around the edges, reservoir not cracked, cover in good shape. Brake fluid on or near the switch likely leaked from above.

 

Mine was leaking from the underneath the cap due to a bad cover gasket. Make sure that when you are stepping on the pedal you don't have fluid spewing out from underneath the cap.

 

Alright, I'll go and double check everything. The resevoir is not wet on top or the sides which would indicate a leak from the top and the seal inside the cover is still soft and pliable and makes one hell of a seal when I try and pull it off. Going on what you all have been saying, it's the bottom of the master cylinder that's leaking. I hope you're right (and I hope not because they're expensive hehe)!

 

Well, I took it into the shop today and they looked at the leak. Turns out that the switch on the proportioning valve has an o-ring on it that went bad. New o-ring and poof, no more leak! They also bled the breaks which really stiffened up my brake pedal.

The bad news is the brake-light is still intermittant. So, it's either a vacuum problem or something to do with my E-brake that hasn't worked in 10 years...no cable even as each time I put a new one on, a bolt on the underside of the car shreds it. But, I know the brakes work...which is good. hehe