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No brake pressure at all?!?!
#1
Oh wonderful experienced people please share your wisdom with me. Alright...I have replaced the front (rotors, calipers, and pads), back (wheel cylinders and hardware), and the power booster/master cylinder. I bled the master cylinder and all the brakes last night and had correct brake pressure for the first time ever! (car was not running when I did all that) I woke up this morning and had no pressure again what so ever. There is no leak of brake fluid anywhere. The fluid levels in the master cylinder are the same. I am thinking that it might be a vacuum leak from the power booster to the intake? please help me out Smile
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#2
Is the pedal hard or does it go to the floor?

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

[Image: 1_12_09_14_10_15_11.png]
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#3
Thinking bad prop valve.
Leaking internally causing a loop back to the master instead of pushing fluid to the calipers and wheel cylinders.

If the master is leaking into the booster you would see the fluid level drop in the master.
Usually no pressure would mean the master is bad, but you replaced it.

Unless the push rod is the wrong length and each time you pumped the pedal you damaged the master, through the booster.
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#4
When I completely bleeded the entire system the pedal felt exactly like it should. The pedal started applying pressure almost immediately. The next morning I got in and the pedal goes about 80% to the floor board then the last inch or so applies enough pressure to prevent the go from going. Is there a way to check the prop valve? or could I take it off and clean it up?
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#5
Do you still get fluid out of the bleeders? This would help narrow things down a little bit. The pedal in my car is really soft, but I still get pressure to half my brakes, just the rears don't work. My prop valve is completely blocking the rears. You can also check this by seeing if the Brake Switch is in the closed or open position (Just ohm across it) if it's closed it means your distribution valve has biased all the way to one side.

2013 Ford Focus SE Flex Fuel 5spd - Daily Driver
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#6
You still have air in the lines would be my guess, or a bad master (it happens). a vacuum leak would cause a hard pedal. Pop the lid off the master and look at the holes in the bottom and see if there is a bubble of air. Do you have good pressure at all wheels when you bleed them? What happens if you pump the pedal several time?
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#7
Alright did a lot of redoing on most of my brake system in general (also...replaced vacuum line to intake and redid back brake adjustment). I have a semi different issue now. When car is off I have full brake pressure after maybe one to two pumps of the brake pedal. When I turn the car on...the pedal almost goes completely limp. I have to pump a good 5-10 times to get barely any pressure at all. If I stop pumping and give it like a 5 second break the pedal is almost completely limp again. I am lost but I am just going to google it a lot more. Hopefully someone knows that little trick of the trade that I have no clue about. Thank you all!

(FYI I have not re bled the entire system again. Waiting on a friend to help me out in the next hour or so. Hopefully that will fix the issue?!?)
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#8
I would wait till you bleed the entire system. Also to the OP I had a similar issue where I had air trapped in the prop valve. even though no air would come out the wheel cylinders.
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#9
matrixx;128857 Wrote:I would wait till you bleed the entire system. Also to the OP I had a similar issue where I had air trapped in the prop valve. even though no air would come out the wheel cylinders.

+1

Doc

[Image: 6y14ea.jpg]

Project started 8-7-10
Completed: All new suspension, rebuilt 351C H Code bored .030 over with mild cam and intake, new 3.50 TracLok, custom exhaust system
Current "mini-project": interior upgrade Undecided
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#10
How long did you bleed each line? I spent almost 30 minutes bleeding each of mine (traditionally - not vacuum or pressure bled) before I was convinced that there was no more air in each.

Believe me: There were times I was convinced that there was no more air in one of the lines, and decided to pump it three or four times just to make sure. As if Murphy were watching, I'd get air in the system on the last test stroke. This went on for ages.

Good to have two helpers too - one to pump, and the other to fill the MC.

-Kurt

[Image: satellite-valiant-mustang-license-tags-signature.png]
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