Classic/Antique Car Repair/no brake pedal

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Expert: - 3/22/2011


Question
I just bought  a 1960 chevy belair with 305 engine and 700 r 4 tranny .The cart has 1970 nova  disc front brakes and a 1992 geo metro power booster and master cylinder .With the vacuum hooked up I have no pedal(goes right to the floor) .If I unhook the hose  on the 600 Holley then I have good pedal ? The resevoir is full/no air in lines /no leaks and brakes are adjusted good .Can you tell me how to trouble shoot this problem as I have tried everything my son and I know to do

Thanks In advance Bob

Answer
The first thing that comes to my mind is the size of the master cylinder bore. The metro bore is only about 3/4 of and inch while the Nova cylinder is over an inch. It is more than likely that the metro cylinder just does not displace enough fluid to activate the Nova discs plus what ever is on the rear of the car. Beyond that there could be a problem with the way the set up was installed, the proportioning valve, the pedal linkage, and more. But I would start by making sure that the master cylinder had enough capacity to fill the hydraulic lines and cause pressure.  

Classic/Antique Car Repair

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Brad Sears

Expertise

All automotive including antique and collectible. However if the car has been modified I can only answer in general terms and maybe get you pointed in the right direction.

Experience

Automotive tech instructor. Syndicated auto columnist 1970's though the early 1990's. Syndicated auto radio talk show, Ask Brad About cars, CBS Radio 70's through 90's TV Show "Last Chance Garage" 1980's PBS-TV syndicated. Auto instructor for the following companies: Fram Autolyte Holly Carter AMF Ford Motor University Of Conn Blue Hills Technical School Sugar River Technical Center Grew up in a family garage in Needham Mass and turned wrenches from the age of 14.

Publications
Manchester Union Leader, Nashua Telegraph, Motor Service Magazine, Yankee Magazine, Popular Mechanics (Saturday Mechanic early 80's), Los Angeles Times, New York Times, and lots more.

Education/Credentials
More than I care to remember. Basically Franklin Technical Institute in Boston, Northeastern University, Fitchburg State Teachers College, Tufts University, and a lot of factory schools along the way.

Awards and Honors
Moto Award winner. And much more.

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