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#1
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69 Bonneville Brake problems
Has anyone had problems with new or rebuilt master cylinders?
I had a problem with the front brake locking up, proportioning valve was stuck, dirt in lines. Cleaned it and flushed lines, worked until this spring. Calipers sticking, replaced with rebuilds, lost all brake pedal, plus old proportioning valve started leaking, I replaced it a unit from an A body, didn't help then with a Wilwood manual adjustable unit. Still no brakes on front, just rears. Appears to be a bad master cylinder. So far I have had 5 different ones on it from new to rebuilt and one from a car that was working. Pedal goes to the floor on all of them. No loss of fluid, no leaks. Have bleed over and over , no better. The rear brakes will lock up, no front. Replaced calipers with a 2nd set, same result. However If I clamp off the front hoses, I get full pedal ! If i take the clamp off the left side I get good pedal, it still locks up the rear first, but it will stop the car. If i clamp the left and release the right side, no pedal, car wont stop. All these always lead back to a bad master cylinder, but everyone I try has the same result, low pressure seams to be the factor. Has anyone had this problem? Any suggestions.... |
#2
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I'd post pictures of your setup, especially the lines. Sounds more like something with the lines or the delay or proportional lines. maybe things are hooked up wrong.
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My Break Away Squad 1969 Fbird (Base, 350 & Sprint Cvt’s - 400HO & TA Hardtops) 1969 LeMans (2dr & 4dr Hardtop and a Cvt) 1969 LeMans Safari 2 seat Wagon 1969 GTO (2 Cvt, 2 Hardtops & Judge Hardtop) 1969 Catalina (3 Cvt’s & a 2dr hardtop) 1969 Ventura 2 Seat Wagon 1969 Executive 4dr Sedan 1969 Bonnie Cvt 1969 Bonnie 3 Seat Wagon (2 of them) 1969 Bonnie Brougham (4dr Hardtop & Cvt) 1969 Grand Prix SJ (2 of them) 1969 2+2 2dr Hardtop (Canadian model) |
#3
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Lines are all as they came from Pontiac. Only change is a willwood manual proportioning valve that didn't solve the problem
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#4
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Quote:
This would seem to indicate the problem is between the clamp and the right caliper? Does fluid come out when opening the bleeder on that caliper? When pressing brake pedal with clamp on and brake bleeder open, release clamp. What does it do?
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John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
#5
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Are the bleeder valves on top or bottom?
Had to ask because I've seen it happen more than once. Wrong caliper for that side puts bleeder valve on bottom. Which makes it impossible to bleed the air out. Clay |
#6
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Thanks everyone, problems solved, just air trapped in line
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