Brakes: Brakes Building up Pressure

[rew]

Hi,
Trying to figure out why my brakes on my 55 E7 PU are building up pressure until the brake lights come on. I've tried changing brake light switch, fluid, just don't know what's going on. Can I get some help from the experts...

Thanks
Randy

[TWChamp]

Make sure the brake pedal is adjusted to come all the way back and the push rod for the master cylinder is adjusted to allow the piston to fully return to uncover the small hole that lets the fluid return to the reservoir.

[BRUCESTUDE]

Also check condition of brake hoses; old rubber lines can separate internally and cause a "check valve" condition.

[studegary]

I also think that the most likely cause is what TWChamp posted.

[Ron Dame]

I also think that the most likely cause is what TWChamp posted.

I agree, but check those hoses anyway for safety's sake.

[wdills]

TW Champ is right. You can't adjust the pedal according to the shop manual. When your pedal is all the way up, make sure the push rod going into the master cylinder is loose enough where you can feel a little movement when you giggle it with your fingers. Not a very scientific description, but it works. Had the same problem on my Hawk and Dad's 50 Champion.

[RadioRoy]

Also make sure that there is a return spring on the brake pedal linkage so that the master cylinder is not the only thing that is returning the brake pedal to the top.

[wdills]

To add to Roy's comment, make sure that spring is installed in the correct direction. I got one car with the spring installed where it was constantly applying the brakes.