57 power brakes not working
August 28th, 2018, 08:03 PM
#1
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Join Date: Feb 2012
Location: Pittsburgh, PA
Posts: 76
57 power brakes not working
I have a 57 olds 98 with a vacuum brake booster. The brakes don’t seem to be working much at all and the pedal is very hard to push. The check valve is working properly and I can’t find a leak anywhere. Everywhere I’ve the diagnosis is that there isn’t enough engine vacuum. The vacuum booster is ultimately fed by a vacuum connection on the center carb (3x2 setup). The center carb engine vacuum and the mechanical actuated fuel pump/vacuum pump both supply vacuum to the brake booster through this connection.
My question is, shouldn’t the engine vacuum be irrelenvent because the mechanical vacuum pump is also supplying sufficient vacuum? The booster was just rebuilt last year so I’m skeptical it’s the booster itself, unless it’s stuck somehow.
My question is, shouldn’t the engine vacuum be irrelenvent because the mechanical vacuum pump is also supplying sufficient vacuum? The booster was just rebuilt last year so I’m skeptical it’s the booster itself, unless it’s stuck somehow.
August 28th, 2018, 09:09 PM
#3
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Join Date: Feb 2012
Location: Pittsburgh, PA
Posts: 76
Only 12-13 in but I think I can improve that by adjusting the jets. I have the vacuum fittings and vacuum lines that match the shop manual. The vacuum pump produces like 20” of vacuum which I would think would be enough regardless of the engine vacuum.
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