Leak from square plug under dash

[GadgetPhreak]

I noticed that there is a square plug that is leaking brake fluid under the dash but can't find it in the parts diagrams. I pulled this image from the web and circled the area where the square plug is located. I also ordered a repair manual from EI but it doesn't arrive until tomorrow and I want to get another parts order in soon. Can you guys identify what it is that's leaking and offer suggestions on how to proceed?

Thanks,
Ben

[pcolette]

That's actually a rubber bumper that the clutch and/or brake pedal arm rests against when not depressed. My best guess is that your clutch master cylinder, located directly above, is leaking at the piston end (hidden from view) and is dripping down the inside of the pedal block until it hits that rubber bumper. The clutch system uses brake fluid. The master cylinder can be removed and rebuilt relatively easily. The rebuild kit is #7103265090 and is about $40.

[GadgetPhreak]

Thank you.

That's what I hoped as I'm already re-building the clutch master and slave cylinders.

Ben

[GadgetPhreak]

What is the general consensus on re-building vs. installing new Master and Slave Cylinders? I want to build this to last the next 40yrs so my inclination is to install new. But there are a lot of other areas to address so I don't want to spend money needlessly either.

Thoughts?

Ben

[Haf-e]

I would rebuild the cylinder and see what happens - if it still leaks then consider having the cylinder redone with a stainless steel liner. There are replacement cylinders available but I would prefer a one rebuilt with a factory / oem kit and the stainless sleeve instead of an pattern part made in India myself.

[Jimm391730]

Our 710M had a leaky clutch master when we bought it; I "rebuilt" it with the new seals. But it still leaked ever so slowly, and years later I decided that for $100 I'd just replace the cylinder and be done with it for a long time.

[GadgetPhreak]

Jim,

Did you re-build or replace the Slave Cylinder at the same time?

I hear that it's best practice to do both together, I haven't checked to see if the slave is leaking yet..

Ben

[Jimm391730]

Did you re-build or replace the Slave Cylinder at the same time?

Nope, I've never touched it in the 12 years I've own the 710M; nor had to do either for the 15 years I've owned the 712W. But I have tried to flush they hydraulics (lockers, brakes; can't remember if I done the clutch, or had it done) every few years. Flushing with fresh fluid, getting the old fluid and any contaminants out may be worth a lot to the health and longevity of the systems.

[HawaiianGauer]

Did you re-build or replace the Slave Cylinder at the same time?

Nope, I've never touched it in the 12 years I've own the 710M; nor had to do either for the 15 years I've owned the 712W. But I have tried to flush they hydraulics (lockers, brakes; can't remember if I done the clutch, or had it done) every few years. Flushing with fresh fluid, getting the old fluid and any contaminants out may be worth a lot to the health and longevity of the systems.

Sorry rookie question here...is flushing as simple as disconnecting a line "at the end" and pumping the clutch or brakes until no more fluid comes out? Or is there a preferred, specific method?

[rmel]

No need to disconnect the hydraulic line, there's a bleeder valve on the Slave.
Flush liberally! I flushed all my hydraulic lines this winter to find a fair amount
of crud in the clutch system, took over a 1/2 a bottle to clean that out. A lesson
learned to flush regularly e.g. once every two years.

One reason rebuilds fail is pitting in the bore, this is a good sign the fluid absorbed
a fair amount of water. Brake fluid is Glycol-ether and is hygroscopic -- absorbs water.
If you don't see any pitting chances are the cylinders are good for another decade or two.