The Stovebolt Site Forums The Shop Area Driveline Bleeding Brakes

Have an 82 c-10, replaced leaking rear wheel cylinders and shoes, and hose. Refilled master cylinder and while trying to bleed system, found I can not open bleeder valve on either front caliper. Don't want to put penetrating oil on bleeder valves as it may contaminate brake fluid. Would a little heat be ok? Or should I just replace the calipers?

Never a bad idea to replace the calipers, Tommy. Odd that they won't break loose, though. Usually those are not over-tightened. I wouldn't worry about penetrating oil contaminating the brake fluid, though. You should only get a tiny bit (if any) in there if you just apply it around the threads. Something like liquid wrench or kroil might help.

Heat the bleeder screws with a Propane torch and touch a candle to the bleeder while it's hot. The paraffin will do a good job of loosening the thread, and it won't make it past the tapered seat of the screw to contaminate the fluid. Also, use a 6-point deep socket and a ratchet on the bleeder screw instead of a wrench.
Jerry

Any possibility they are left hand threads? Just a thought.

Not a chance.

Just remember brake fluid is flammable if you use a torch...don't want any accidents.

There used to be a repair kit to fix it when it breaks off in the caliper.
George

Calipers at Rock Auto: $15.32 right or left.

Ok, I got the bleeder valves open, just needed a little more pressure. Now the next issue, the Brake light on dash will not go out. How do I get the valve/ switch in the combination valve to center itself, so the light goes out? I don't remember having problems like this years ago when bleeding brakes.
Any help would sure be appreciated.

Hy Tommy, the shaft which activates the brake warning light inside the combination valve has shuttled over because of a difference in pressure between the two separate braking circuits. Some combination valves have electrical connections which can be unscrewed, if you have good access you could see if your connection will unscrew, if it will unscrew it and look down inside the switch, you should be able to look down inside and see where the shaft has moved one way or the other, the shaft has a low area on it which should be in the center of the switch port. I have had some success putting a small shaft down the hole, applying moderate down force and dragging the shaft back to its centered position. I hope that works for you, good luck. There are tools available that can be put in place before you bleed the brakes which hold the shaft centered while you bleed the brakes.

As 3B noted, you can remove the connection by unscrewing it and using a pick, small screwdriver, nail, etc; reach into the valve and recenter the plunger. Not too hard of a process. Good luck.

Opening bleeders one at a time on alternate ends of the system and gently applying the brake will also center the switch. Just use short, gentle strokes on the pedal. It doesn't take much force to move the shuttle valve back and forth.
Jerry