'67 Mustang - My power brakes aren't working. I have to press almost to the end of the pedal range to get brakes to start working.

Power discs on the front. Drums on the back. Fluid reservoir is filled up and not decreasing since last week. I took both back wheels off and found a seized right rear self-adjuster on the drum brakes. Unseized it, but still have the same problem.

What do I try first??? Bleed the brakes??? Buy a new self-adjuster to put into the back drum???

It seems like if I "pump" the brakes, I can build up pressure in the power brake system, but it doesn't hold.

No leaks anywhere to be found in the lines.

Any comments??? Thanks in advance.....gpateman

 

Hmmm....

Normally, if you have to pumpthe brake pedalto get a "good pedal", this is due to air in the system and pumping the brakes is actually pressurizing the air within the system.... but the pedal should hold after you've pumped it.... unless the diaphragm in your PB booster is shot and is leaking.... can you hear air escaping from the PB booster?

I'd bleedthe brakes first, but I'm thinking you may have a bad booster.

Dave

 

If it was a bad booster the pedal would be hard as a rock.. It sounds more to me like you have some air in the system. Or you may have an adjustable brake plunger.. I think thats what its called.. You may need to pull the master cylinder off and adjust the rod out or in a little to make it work correctly. Get on autozone.com and look up the instructions for replacing a master cylinder. It will give you the scoop on adjusting the push rod in the master cylinder..

just my $.02

 

I can't hear any air escaping.
When I pump the brakes 3 or 4 times driving down the road, I can build pressure each time........it will hold some pressureif I pump on that 4th time and hold the pedal down........but if I release the pedal and wait a second and try to press brake again - no pressure - all of the pressure is gone again.

 

Air in system-bleed brakes.

 

+1 Best and cheapest place to start. I'd repair that rear wheel and anything else first. Brakes are THE most important thing in your car. I never screw around with them. Fix them and fix them right.

 

Thanks for the replies......I'll bleed the brakes and replace the self adjuster on the right rear brake........if I'm still having trouble, I'll post again.......thanks for being so quick......this forum Rocks!!!!

gpateman[8D]

 

As I have learned over the years, start with the cheapest and easiest fix and work your way up from there

+1 on the bleed (easy and affordable!!)

 

Why do you have air in your brakes all of a sudden/

Bleeding the brakes is just the first solution. You need to determine why there was air in there to start with. Look at your rubber lines for cracking and repair / replace on condition of craks. Also sometimes the act of pumping them up temporary fixes a bypassing MC shuttle valve. Personally, I think your MC is failing and you should replace it.

 

bleed them. then mabe check if you have vaccume from your manifold, if you have a real radical cam this can sometimes be an issue. check the hose from manifold to booster. its most likely just air bubbles in the lines