I am having problems with my 1960 F100 rear brakes. What's going on is when I press the break pedal the rear breaks expand to stop the truck...Great. The problem they will not decompress keeping the rear breaks locked. I have changed the Master cylinder and Wheel cylinders the only way I can get them to release is break the bleeder screw, and squeeze the pads together then try again. if it sits a couple of days they will decompress on their own. My thoughts are that maybe there is a blockage in the lines just letting fluid go one way or maybe I have been given the wrong break pads???? Not sure anyone have any ideas.
Have you replaced the flex hose on the axel housing. I've seen these hoses break down internally. It actually acts like a one way valve. When you step on the brake, you have a tremendous amount of pressure which forces fluid to the wheel cylinders. But when you let off, you only have the force of the return springs to push fluid back. This may not be enough to overcome the internally damaged flexhose. Good luck.
On the rear I have metal lines all the way to the wheel cylinder it was like that when I got the truck. I have tried to upload pic but can't seem to get them to load not sure what I am doing wrong it ask me for the URL of the image?
There should be a flexhose that connects the steel line from the truck frame to the steel lines that run to the wheels. This allows the rear suspension to move up and down. Another possible trouble area could be the contact surfaces on the backing plate. On older cars and trucks they sometimes get ridges worn in them. The brake shoe gets caught on the ridge and can't retract completely. These can usually be filed or ground smooth again. Good luck.
If it is only the rears doing this, it is something in the line from the junction block (where lines from the front brakes join the line to the rear) to the rear. If it is both rears doing this, it is probably not a problem with the steel line on the rear axle.
One thing to try. Next time this happens, instead of opening a bleeder at the wheel cylinder, loosen the line right at the master cylinder. If this does not let the rears release, you have isolated the problem to the line to the rears. Then find the flexible line that goes from the steel line on the frame to the steel line on the rear axle. Loosen the connection between the steel line on the frame to the flexible line. If this does not let the rears release the problem is in the flexible line or the tee fitting on the axle. Replace the flexible line and remove the tee fitting, clean it out (I have seen debris from a bad flex line plug a tee) and reinstall it.
Also another thing to look for is a pinched or crimped steel line.