Today I brought home my first muscle car; a 71 chevlle. There are some problems I have with it however, mostly /w the brakes. For some reason theres no brake light switch in the car, no idea why, and the pedal is WAY harder than should be for power brakes. They do work, if I stand on them.

The guy I bought it from said he added disks to the front, and what I'm trying to figure out is whether or not he was messing with the master cylinder and booster. The brake pedal doenst look like its returning all the way. Under the Dash there is a factory bracket that has two holes in it for- im guessing here; a cruise control switch and a brake like switch. at the bottom of that theres a small rubber bumper. The brake pedal arm is about an inch and a half from that at rest. Should it be touching the rubber stop?

Secondly are there any casting numbers that I can look for on the Booster or the Master cylinder to see if they are correct? I can see a portioning valve down below on the framerail. If he changed from Drums to Discs in the front and didnt change that would it cause my problem?

Btw if anyone could tell me the stock wire color under the dash and what harness its in so i can get a switch in this car and hopefully drive it for a few days before its snows here in michigan.

thanks for the help guys.

Most people don't remember to swap the proportioning valve for the drum to disc swap. You need to make sure it is replaced with the correct one. As for the brake pedal, there is a post coming from the brake booster and it needs to be moved to the higher hole on the pedal (or lower I cant remember for sure but you can do a search... Im almost positive it is the upper). The two holes on the bracket in front of the brake are for the rear brake lights, you will need to move this switch too.
POZ

Something else to consider. If you're running a cam with a lot of overlap, the engine won't produce enough vacuum to allow the booster to work. It needs 18-20" of vacuum to work as the factory intended it to. This will make you dirty your shorts when you try to stop. Hydraboost or an electric pump will solve this IF this is the cause. A bad booster will cause a hard pedal too. Try this where there is no traffic, drive car, downshift to 2nd, letting revs increase while coasting, if brakes improve it's a vacuum problem.
Hope this helps.
Rick

I was trying to test the booster in the drive way last night. I reved up the engine and let the throttle close quickly to see if I could generate some vacuum. But without loading the engine and not having enought vac hose on hand to get my vacuum gauge where i could see it while applying the brakes made it hard to see if it was working. This didn't seem to help any. I did check the Vacuum on the motor and warmed at idle i was barely making 15"

Currently the motor has a dead cylinder due to whoever had it before me understanding that headers get hot and pulg wires are not made of asbestos. Im going to fix that and go throught the idle mix and speed before I mess with the brakes any more to see if I can get any more vacuum out of it.

Right after I go try the 2nd gear thing.

I did a search on the the brake pedal arms, the consensus seems to be that with the setup I have the push rod needs to be in the lower hole; which it is. I will not even attach to the upper hole, the angle from its attachment to the booster rod makes it interfere /w the firewall.

I was having a problem with getting the brake Light switch to contact the brake pedal arm, I have it kludged up for now so i can drive it if i want. But does anyone know a source for the bracket thats supposed to attach to the unused upper hole on the arm?

It was a hoot to drive tho, the cars got problems but none of them is major, and I heard the greatest thing EVER the other day after I finally took the wife for a ride.

"So what do you think honey?"
"Oh its great, I like it"
"You want me to make it faster?"
"Oh yea."

My wife rocks.
:thumbsup:

The piece that activates the brake light switch is called a "striker" which is a sheetmetal part that attaches to the brake pedal. I have no clue if they can be bought anywhere. The alternate method is to make something yourself that attaches to the upper hole in the brake pedal. An other way is to put a long sheetmetal screw into the end of the plunger of the brake light switch that will contact the pedal.
As for the firm pedal, it could be that you have a bad booster. When they go bad the brakes are really hard to work. Another possibility is that the booster and master cylinder are not properly matched. Some master sylinders have a deep hole in the rear of the piston, which I think is for non-power brakes. The cylinders that I have seen for power brakes have just a little dimple in the rear of the piston. It would take only a few minutes to check that out. Some boosters have an adjustable pushrod, but most Moraine boosters seem to be non adjustable.

Turbine,
How'd the brake situation work out? Any solution to your problem?
Rick