79 truck with hard brake pedal

[bradf74]

Ok now that re-read that it does draw a chuckle...

79 been sitting up for about a year. Just got it running. Manual discs in front and drums in rear. Drove it about 5 miles on a shake-down run and the brake pedal got stiffer and stiffer. By the time I got home I had about 25% brakes with Maximal effort the pedal would only move half an inch.


What do I replace first?

thanks

[N2TRUX]

WOW! That's a good one. Normally I would say your vacuum booster is bad, but you don't have one. I didn't know that they even offered manual discs in 79.

Check your wheel cylinders and report back.

[wheels67]

Agreed. Caliper pistons/ wheel cylinders are frozen. Gonna have to pull rear wheel and drum, have someone press brake pedal and see if cylinders push out.
For front pull wheel and unhook caliper and pads to see if piston is working.

It is kindof weird to not have a booster for 79.........master cylinder is next....

[bradf74]

I got in it today just to move it in the yard and I had a good pedal. I got rear wheel cylinders to change out but then I remebered that my brake light (in the cab) has been on since I got the truck running.. could it be a prop valve?

[spinem]

go faster! haha jk. but wow. thats a stumper.....hummmmmm guessing pistons are shot... but why would it progressively worse? worse /w/ heat maybe? damn man. thats a good one, maybe the proportioning valve?

edit::::YESS!!! CHECK THE PROP. VALVE!

[bradf74]

How do I check the prop valve?

[jchav62]

I would bleed the system. I had a similar problem a while back with my old '51. Turns out it had air in the system... in driving, air would expand, locking the brakes. Sometimes I would have to pull over and open a bleeder screw to get back going again...

Good luck... and if I were you, I'd add a power brake booster.