Reseting a brake combination valve

[langleylad]

One of the rear disc brake pads ( SSBC conversion ) decided to fall apart on my 88 S10 2wd , shortly after when I applied the brakes the pedal almost hit the floor and the brake light came on for a short time then went off . I have repaired the rear brakes , now I need to reset the combination valve as the rear circuit has been closed and all the pressure is to the front . There is now a noticeable amount of drag on the front brakes . I've done some reading on how to reset the valve but it's not quite clear to me . So how do I do this ? please

[Mr4Speed]

I've seen such a thing happen where the piston in the combo valve got stuck in one end, and it won't go all the way to one end unless the pedal goes to the floor due to a failure or during bleeding. Tapping it with a hammer may pop it loose, but it's probably stuck because there's gunk in it. Taking it apart and cleaning it out would be best. There's not much to them.

[langleylad]

They are designed to shut down the system where the problem arose ( rear brakes ) . From what I've read I need to bleed the front brakes . This causes pressure on the rear system , which in turn centres the valve in the unit . Will try this method out shortly . The unit is not serviceable .

[NewEnglandRaceFan]

bleed the fronts, once bleed, crack the rear and have someone stab the brake pedal hard quick and fast.. and the person at the w/c ready to shut the bleeder fast.. then just a few pump um, hold um. and you should be good.

there maybe a pin to push or pull while bleeding on the p/v

[yellomalibu]

bleed the fronts, once bleed, crack the rear and have someone stab the brake pedal hard quick and fast.. and the person at the w/c ready to shut the bleeder fast.. then just a few pump um, hold um. and you should be good.

there maybe a pin to push or pull while bleeding on the p/v

I've heard this, as well. No steady, firm push, but like a serious "stomp" like you are trying to rip the brake pedal off the firewall.

[Beagle]

huh. Mine would set the light when the master cylinder died and reset when I put a new MC on it. I don't remember ever having to do anything else, but a new MC means the brakes get bled so there may be something to that.