eddie jr

Well, for some unfortunate reason the brake light is still on after my brake repair. I blew an axle line so i replaced both axle lines from the rubber flex hose and the rear left wheel cylinder as it was leaking a bit.

I bled the rear right first doing the up-down scenario since gravity bleed wouldn't work initially. Did quite a few repetions long after fluid came out. Then it started gravity bleeding great so i let that one go for a bit. Then gravity bled the left one for a while (always watching the MC).

Then when i went out for a drive, the light was still on and stayed on the whole way. THe pedal seems pretty good and does not go down really far and does not feel spongy. It also stops pretty damn quick...............so any idea what is up with the light still being on???

thanks.

eddie jr

Anyone? I am pretty stumped here.

1988-305-tbi

I THINK THERES A SENSOR/SWITCH ON THE PROP VALVE THAT TURNS ON THE BRAKE WARNING LIGHT, TRY MESSING WITH THAT TAKE IT OFF PUT IT ON .. SPRAY CONTACT CLEANER ON IT

eddie jr

Well, before my little holiday i tried bledding again....nothing. I then took the harness fo the pressure switch and it went out. I then put the parking brake on and it went back on. So the witch is tripping it for some reason. I don't know if maybe some air did get in there but i would think that the brake pedal would be spongy.

Wild Weasel

There is a switch in the prop valve. The switch is a slider. To turn it off, you will have to do a little playing with the bleeders in the front and the rear. Try bleeding a little off the front brakes to slide the switch the opposite direction. When you lose fluid in the rear the switch slides to turn on the light. You have to slide it the other direction to turn off the light. Sometimes it takes just a bit one way or the other to turn it off.

squirted1

iTrader: (2)

a couple heavy pedal applications should re-center the switch. there will be a light "pop" when it does that you will feel in the pedal

eddie jr

Well, I ended up bench bleeding the master, put it back on, bled the rears, noticed fluid got inside one drum (turns out it was leaking through the backing plate not the wheel cylinder, but there was a small tear in the rubber boot). So i then replaced the wheel cylinder and even with the reservoir closed it drained in a matter of minutes when other times gravity bleeding wouldn't even work . So off came the master again to bench bleed, bled all 4 brakes, and guess what...............light is still on!!!

Hard pedal applications did nothing unfortunately. Pedal does feel good though.

naf

iTrader: (7)

The light is controlled by a ground wire to one of two places. A switch on the prop valve and one on the parking brake. If you pull the lead off the prop valve and the light remains on the problem lies at the parking brake switch (or a short in the wiring somewhere grounding the circuit).

Losing fluid at the MC will trip the switch in the prop valve. IF everything is back full and properly bled the switch SHOULD reset itself after a few brake pedal applications. Your prop valve does have some age and depending on how dirty the fluid was, trash could possibly be preventing the switch from resetting. Perhaps a light tap or two may help.

eddie jr

Tested the PB switch and it is indeed the pressure switch setting the light.