Brakes: someone please explain this to me

how did you bleed the air? start from the wheel farthest from master and go to the shortest. also make sure the bleeders are on top of the cylinder.

 

Yeah, the total volume of all those brake lines has to be no more than a few ounces (20 ft of 3/16" ID line equals 3.7 fluid ounces). Did you bench bleed the MC?

 

all bleeders are on top (they wouldn't fit any other way).
brakes were bled farthest to nearest.
Master Cylinder was bench bled until no bubbles would show front or rear.
I have since pumped about another 1/2 cup through that front brake and still getting air...? I have worn out the brake legs of two kids and am not getting anywhere

by the way, if I pump the pedal rapidly I can build up and hold pressure in the system. If I just stab it, all the way down.

 

Went High tech on it and broke out my vacuum bleeder. topped off the MC and drew 25 inches of vac on the driver side front. steady air bubbles in a flow of fluid. after emptying the 4 oz container on the vacuum pump 3 times (and keeping the MC topped off), I have drawn the conclusion that the MC must be allowing air in around the seals on the piston. there is nowhere else in the system that I can think of that could let air in but not let fluid out.

gotta stop now for family activities, but at least I have something to start with tomorrow...

 

With everything very quiet around, you may be able to hear where the air may be sucking in when a helper pooshes the pedal. Doing this recently, I heard an air leak in the brake switch itself. Just an idea.

 

Heres my 2 cents. Brake line is leaking air, If it were the mc both brakes would have air in them.

 

I just got back from about a 5 mile drive in the $ sink, even passed out a few jeep waves...

this morning I pulled out the second rebuilt MC I bought, filled it with fluid and bled it till I got no more air. I put it in the jeep, hooked up the lines and pedal, pushed the pedal twice and...



I got pedal even before I bled it

a few minutes of work and I was able to driveway test it... 4 brakes working in unison. this is great...

one last thing I will have to get used to, I have not been able to apply the brakes without pumping them since I bought the sink...

guess I'll be paying a visit to advance auto to discuss that "lifetime guarantee" they made such a fuss about when they sold me the MC:twisted:


lastly, thanks for everyone's input. right, wrong or indifferent, any ideas are welcome when battling mechanical difficulties:stout: :stout: :stout: