Technical Disc brakes building pressure

I have been experiencing the brake pressure building up on my 34 Dodge with disc brakes. All of the components are 2 1/2 summers old and use. Just wondering if you guys can help me out on what would cause this and what is the fix.I know this is the problem because I have jacked it up when I got home and the wheels spin tight. After it cools down they seem to be ok.
thanks,
Joe

 

Shorten the brake pedal rod just a tad bit. More times than not, is the fix for that.

 

I had that problem on my 66 Suburban, first test after power disc install the truck would slow down coming up to a stop. A little free play adjust did the trick.

 

Probably not the problem on this, but I've run into collapsed brake hoses on stockers with some miles on them. You can't tell by looking.

I'll second the no play in the brake pedal. I've also seen the bleed back hole in the MC plugged too.

 

Are you running a vacuum booster? If so the rod between the booster and M/C needs to be adjusted or shortened properly so you have a slight gap, same goes for the brake pedal to booster rod.
If your running manual brakes then the brake pedal to M/C rod clearance is all you need.
Always use a good strong pedal return spring.

 

Being that it worked for 2-1/2 years, I would first look at the brake pedal pivots to see if they may possibly be binding and in need of lube and at the same time check that the return spring is doing it's job. If that seems OK, follow up with the previously posted advise on checking free play and brake hose condition.

 

Has the problem been there all along for 2-1/2 summers?
Or was it fine up until now as the problem just started??

 

quick test, put some 1/16th fender shims between the master cylinder and booster, take it for a spin and see if it changes.
if so, the rod between the booster and cylinder needs to be adjusted.
(speaking from experience....)

 

man, that is a great idea!

 

If the master cylinder under the floor, do you have a 2# residual valve in the line?

 

Some calipers come with phenolic pistons. They swell up after a few years and start causing problems like this.

 

The reason the piston needs to fully retract is there's a tiny hole in the bore that allows residual pressure to return to the reservoir, when the pedal is depressed and released there should be a small " geyser " of fluid shoot up in the reservoir. If you can't see this take place your relief hole may be plugged up,( I have had this happen)

 

I appreciate the info, there is a lot to take in. There is no booster and the pedal is under the floor. I just remembered that when we took the disc brake ***embly apart to put steering stops on that my buddy noticed the caliper cylinder was not working correctly due to a ridge or similar. He ground it out but This is Speedway stuff so perhaps I need to change out. I will start with some of the suggestions. Thanks, Joe