P1800ES Brake warning valve

[2robert4]

After changing the brake fluid on my vehicle the brake warning light stays on at all times (which I assume means that the shuttle inside the Warning Valve has been forced over to one side due to over zealous pumping of the brakes). To try and remedy this situation I disconnected the harness from the sender and connected a warning light from the positive terminal to the sender so I could observe any change as I bled each side of the valve in turn to try and recentralize the shuttle but to no avail. The braking system works perfectly without any pulling or locking up and there are no leaks.

Can anyone shed any light on how I might sort this situation.

[hairyapple]

You've probably done just what you think you've done and jammed it into a corner. That's just a guess 'cause I'm not familiar with the workings of that valve, but it makes sense since everthing else seems okay (stop lights work?). Maybe some compressed air fed to it in reverse would free it up, or totally destroy it solving the problem altogether. I would locate a source for a working unit first, just in case.

[hairyapple]

Post Script: For future reference-the little compressed air rigs sold to "power bleed" the brake and clutch work quite well and are cheap. You could also easily build one from an old garden sprayer or something like that. Mine just runs off the pressure from a spare tire (5-10 lbs is plenty) or other air storage vessel. Saves a lot of back and forth.

[mike gilbert]

have you removed the warning switch from the valve? If not the piston cannot return to its normal position so it will never re-set.
Disconnect the wire, unscrew the warning switch with a spanner or socket and remove it completely then screw it back in again. This allows the piston inside the valve to return to its old position so that when you screw the pin back in, the circuit will remain broken and the light will be out.
Mike

[B20F]

Just one more thing before you install the brake warning switch back in: pump the brakepedal a couple off times so the piston can come back in it's centered position. And THEN put the switch back in. And when you refresh the brake fluid next time first remove the bsw to prevent this thing happening
Btw: no brake fluid will escape when you remove the bws.
cheers;
Peter

Fyi; at the moment you're only using about 80% of it's brake capicity. Only one rear brake will function and one pair off the front pistons each will. To activate the other rear brake and pairs off front pistons, you must reset the bws.

[c1800]

I was having trouble bleeding the brakes but I was able to bleed the brakes after I had taken the warning switch out of the junction block.

In any event I probably need a new switch at its electrical function is intermittent. It also has no effect on the dash light, but that's another project.

When screwing it back into the brass junction, there was no resistance from the spring loaded nylon plunger. This led me to believe that the piston inside was tripped one way or the other. However, based on the Haynes manual diagram it appears that the sliding piston is in the central position, based on what I could see with my inspection mirror
I.e. the sliding piston is showing the central groove.

Does this sound proper?

Also had a few drops of brake fluid when I took the switch out. is there a kit to rebuild the valve?

Any advice would be helpful. Thanks.