This is a 1 year old GM proportioning valve that was working fine till I pulled the master loose from the firewall. I have no idea why the below circled area would now be leaking? Its a slow drip,but it is not going away. Could fluid have gotten by the diaphram when i tilted the system forward? Or did the diaphram take a crap on me? The leak has slowed which makes me wonder if it will stop? I know it is not coming out of the lines. What is the purpose of this diaphram???
On some cars you would push or pull on the stem to properly bleed the front brakes, can't quite remember, in any case,rough handling shouldn't cause a leak. Over the years I've seen several combination valves fail, thouh not very common. Double check all threaded connections. Spray with brake clean and air dry, hold the pedal down and recheck before you buy a new valve. Good luck, Tom.
What you have is a common factory 3-way combination (combo) valve, and the part you show leaking is the metering, or hold-off valve, going to the fronts. The proportioning valve is at the other end going to the rears, and the center contains the pressure differential switch. The valve should not leak from just being tilted. If this is an important, needed, stock restoration/replacement part, I would buy another. If this is a custom system, I would pitch the valve and use only an adjustable prop valve, and no metering. IMO. Bob
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