Power Brake Conversion

[Reece71]

Our 71 C10 had manual brakes - disc/drum. We decided to covert to power brakes and got a conversion kit from Brothers. It had the booster, master cylinder and proportioning valve all together. We bled the master cylinder, installed it, connected the vacuum to the carb, bled the brakes and took it for a test. The pedal is extremely hard - you pretty much have to stand on it to get it to stop. It's like the booster is not working. Got plenty of vacuum, the check valve is working. I don't know what else I can check. My son and I have been working on this project for a few months and tomorrow is his last day of school is tomorrow and he is dying to drive it before he is out for the summer. Thanks for any ideas.

[wbc409]

I believe that on the brake pedal arm there are 2 positions for the master cylinder rod to attach to. One is for manual brakes the other for power.

It sounds like your booster isn't working

[Custom/Ten]

I don't know if this will solve your problem and I don't know what your setup is(more info might help) but brake boosters are supposed to be hooked up to the intake manifold with a 3/8in hose. Not to the carburetor. See if you can get hooked up the the intake manifold. Can give you more info later but try that first.

[wbc409]

The booster works off of manifold vacuum. You can get that from a port on the manifold or most carbs have a large vacuum port at the base for power brakes

[7tee]

Originally Posted by wbc409

The booster works off of manifold vacuum. You can get that from a port on the manifold or most carbs have a large vacuum port at the base for power brakes

This is true, even though I'd rather have my booster vacuum from the intake...

[jessemthompson]

Sounds like you got a defective brake booster to me. I know I've bought and installed a bad master cylinder in the past. It's man made and bound to happen.

[Custom/Ten]

Oops, CPU error

[Custom/Ten]

Still better to run straight manifold IMO but if he can't then he can't. Seems best to start simple. Your prolly gonna end up returning your unit but if you wanna test the booster you can remove the check valve and put a vacuum pump(pump not gauge) on it and see if it's able to hold vacuum. Also pump the pedal 10 times with the car off then hold it down and start the car. If it drops around a couple inches the booster is working.

Could always just be seized calipers or maybe fade from the rear, after all saying you have to push hard is relative.

When I did my power conversion my setup also came with a different brake pedal pushrod.

Anyway as already stated it's prolly just bad and your gonna have to return it but I thought you might wanna take ten minutes to make sure it's hooked up right and run a couple easy test before you go through the trouble of disassembling and returning. Good luck man!