Expert: Brad Sears - 1/25/2008

Question
QUESTION: I wrote about this problem before I did everything you told me to do, checked wheel cylinders, brake pedal travel and I went out and got a mew master cylinder not a rebuild bench bled it and I still have the same problem. A friend told me that if the proportioning valve is stuck this could be the problem.

ANSWER: It is possible but I have never run into that valve causing this. It seams to me that it is still an adjustment problem. But a few questions here. Is the car all stock? Has it been restored? Has it ever had power brakes?
Brad

---------- FOLLOW-UP ----------

QUESTION: The car is all stock however it as been restored. It came with factory manaul 4wheel drum brakes. The car is a restored matching #'s camaro so everything I've put back is oem

ANSWER: Was the brake pedal and assembly removed during the restoration?

---------- FOLLOW-UP ----------

QUESTION: No the brake pedal didn't have to be removed the floor was in good shape

Answer
Well I have kicked this one around in the old gray matter and the only thing that I can come up with is to first check the free play in the brake pedal. You need to do this with your hand. There should be between one half inch and an inch of free play in the pedal before you feel the pedal push rod contact the piston in the master cylinder. If that is adjusted right, and there are no leaks, and there are no flex lines that are ballooning under pressure, and the brake drums are not turned over sized and expanding under pressure, and there is no air in the system, experience tells me that we come back to an adjustment problem, too much clearance between the drums and the shoes. This takes more fluid to push out the wheel cylinders to make the shoes contact the drums.
Brad