# brakes on a chevy C-60



## mark24409

Can any one shed some light on reparing the brakes on a 73 chevy C-60. the system is a single line master cyl. that runs to a vacuum boost chamber under the driver side of the cab. then out to the wheels. I have replaced the master cyl. wheel cyl. and all lines including the vacuum line from the eng. to the vacuum boost chamber.the pedal is hard but no brakes. I fear that the only thing left is the vacuum chamber. if this is the source of my trouble can I rebuild it or must it be replaced. or I'm I missing some thing simple.


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## paul soccodato

what your refering to is a vacuum booster, which i doubt is your problem. there should be a proportioning valve in the system somewhere, its most likely your problem. when you changed the lines and wheel cylinders, did you bleed the system?did you get fluid out with pressure?


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## mark24409

thanks for your ideas on my brake problem. i have bleed the brakes a couple of time to make sure i got all the air out. As for the proportion valve, i never gave it a thought. thanks i'll give it a try. hopefuly thats the cure to my proablem. I've had a few people tell me that the brake systems on those old trucks can be a bear some times if they start to give you trouble.


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## jakegypsum

Mark, You may not want to hear this but to me it sounds like the vacuum booster is in need of replacement. I have been around many makes and have seen similar problems like yours. They have all shown the same when a problem like this comes around. (International, Ford, GMC, Isuzu). Normally when the brake pedal becomes hard as a rock, it is the booster that is failing. As for rebuiding them, it all depends on availability of parts. I have always purchased rebuilt replacements. Rebuilding something like a brake booster has never been cost effective to me. Good luck. Jake.


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## SCFALL

Mark bad news but I would also say its the booster, I have replaced a dozen of these over the yrs. without the booster its like having manual brakes. You cant push the pedal hard enought to work brakes sorry for the bad news Scott


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## Alan

First, there is no proportioning valve on those systems. I've got a GMC5500 that I repalced all the lines on so I can speak from experience. In addition, on an all drum system there is no need for one. Brake bias, if even a consideration, was engineered into them by varying wheel cylinder size. I'd put my money on the booster, also called a "hydro-vac" is bad.


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## mark24409

*thanks for the info*

Thanks to every one for there replies, I have gotten the breakes fixed. Stops great now , I did have to replace the booster. I'm hoping that it is the end of my brake proablems for a while. since the entire system is now new.:waving:


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## DZLSNOWANDICE

Should be I had to replace the booster on my Dads old 1970 chevy c-60. good for another 100,000 
Frank


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## db688

i have a chevy c60 dump 1976 with a vacuum booster and a single line from the master cylinder . the brakes where none exsistant and the peddle would nearly be bottomed out before any brake would grab. I replaced the master cylinder and had a had a very hard peddle . but the brakes worked until it suddenly released a bit of pressure and now one or more are hung thanks in advance for tips


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## Randall Ave

Possible wrong MC, if you have a hydravac system, the master can not have a check valve in it. Or the hyravac needs to be replaced, these can be a bit$% to fix.


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