Brake light

Sometimes if the hourglass shaped rod in the proportioning valve goes to a fully closed position on either the front or the back line, it will want to stay there. You have to remove the valve, dissassemble it to a point where you can physically help it back to center, then put it back on an rebleed the system.

EDIT: If there isn't a warning light sending unit, then the shaft may not be hourglass shaped.

mustangdave said:

Sorry I wasn't clearer. I was talking about the warning light on the dash.
So is the distribution block rebuildable; mine seems to be stuck. I have rebled the brakes numerous times trying to recenter whatever it is with no luck. I have seen plenty of replacement proportioning valves but never a stock distribution valve.

Click to expand...

It’s possibly stuck but not probably. Some can be hard to recenter. Which one aren’t working, front or back? Let’s say its the back ones that had the leak. The proportioning block has slid over and stopped fluid going to the back. How to correct this is to...

1. Fix the leak in the back brakes.
2. Make sure the back bleeders are closed.
3. Fill the master cylinder.
4. Open and leave open the bleeders in the front.
5. Climb into the car; turn the ignition on so the dash brake light is on.
6. Push the brake pedal moderately until the light turns off, but you don’t want to go to far and slide it all the way over and cut off the front brakes.
7. Close front bleeders.
8. Fill M/C w/ brake fluid.
9. Open the brake bleeders in back first. Leave open until fluid comes out on its own.
10. Fill M/C again
11. Open front bleeders until fluid comes out on its own.
12. Do the normal bleed procedures have someone pump brakes and hold while you crack the bleeder until the pedal goes to the floor. Repeat on other 3 wheels.

Just a little FYI... I never thought gravity bleeding brakes did anything, but working as a mechanic in a general automotive repair shop has made me a believer. It GREATLY reduces the amount of time 2 people are screaming pump "them" and "holding". Sorry for the long detail post but easiest way for me to make sure I was clear.

Graham

Yeah, last time I had to recenter one I was able to get a small screwdriver down that hole and help it along back to center. You will have to loosen the brake lines so when you are pushing the shaft it will release the pressure in one direction and suction from the other. Some types have a bleeder at the front which is handy if you are lucky enough to have to push it in that direction.

The problem that get them stuck is when they are fully closed in one direction. If they are only partially closed they will recenter as blk02 stated because the fluid will have a path to start to build pressure in the line, pushing the shaft back to center. However if you have been driving with a major breach in the line the shaft will fully bypass the port, closing any path to those lines, requiring a manual recenter. The valve isn't exactly "stuck", it is actually doing it's job.