Brake fluid leak

[jpctln]

For a few days now I've had a light browninsh leak that I thought was the usual oil leak but it's actually brake fluid, as I found out today, because it sort of splashes onto the ground unlike oil. It seems to be coming from that plug directly under the master cyllinder. It's a hex-shaped metal piece with a pushable-type button in it (sorry I don't know much about brakes or what it's called), but it seems to be pumpin out of that, dropping onto the clutch pedal bracket, flowing down the clutch cable, and finally leaking on the ground. Why has it just started to leak out of that plug? And what is causing it?

 

[shttygtstang]

you need a new flux compasitor 1912 awaiting

 

[jpctln]

Hey good one. Anyone know what I'm talking about?

 

[Michael Yount]

My brake cylinder's different than yours, but I know that brake fluid leaks are nothing to take lightly. I wouldn't drive the car until it's fixed. If it's leaking enough to see it on the ground, that's HUGE by brake fluid standards. Sounds like it's time for a new cylinder with switches/fittings.

On our cars, there's a brake pressure switch in the junction block below the cylinder which goes bad sometimes, causing leaks just as you describe.

 

[jpctln]

I found a picture of the cylinder assymbly. The fluid is leaking out of where the arrow is pointing to. I guess that's called the junction block, as Michael was saying.

Edit: I just found out it's called the proportioning valve.

 

[Matt90GT]

That is the front plug for the PV in in the combination valve. It is prone for failure because it has a rubber plug in the center of it. What happened is it fell out, thus causing your leak.

When you convert to rear disc brakes, you remove the stock PV behind that cap and install an adjustable unit along the firewall replacing the coupler there. Then you purchase the FMS M2450A plug (solid brass plug with NO hole in it) to replace the stock cap with a hole in it. If you are going to go rear disc, do this to solve your problem.

If you are going to keep your brakes stock, you can go purchase a new combination valve from ford ($50 or so dollars) or hit the junkyard and get another cap from any 87-93 car. Be sure the rubber plug is in there. The cap is under pressure, so be careful when removing as the spring and piston will shoot out.

 

[jpctln]

Thanks for the reply, btw.

How do you go about removing just the cap? By cap, you mean just the hex shaped piece with the hole in it, right? Is it a good idea to bleed the whole system after changing out the pv/cap?