Issue: I cannot gain and hold pressure in my front brakes.


Things I've done: new booster, multiple master cylinders, ALL new brake lines, ALL new brake hoses, new calipers, new pads new wheel cylinders.

Bench blend all the masters. Bled the brakes over and over.. Solid fluid coming out of the bleeders...


Any ideas? Any solutions?

Thank you,
James

 

Ideas, yes. solution, maybe.
When you replaced the master cylinder did you bleed the rear brakes also?
If there is air in those lines it will compress until the pressure in the system is equal and by that time the pedal is down near the floor. Usually bleed RR, LR, RF LF. Also make sure the rear brakes are adjusted to correct clearance. Let us know if the ideas were close to the solution.

 

Yes the rear brakes were also bled. I bled all brakes in-between each new part I put in and yes in that sequence ( farthest
To closest to the master) the back gains pressure and stops so I'm almost positive it is adjusted correctly. I'm thinking of putting in a Proportioning/ combination valve to equalize the pressure.. Any thoughts?

 

If you used direct replacement parts you should not need an additional valve to make it work right. If you were modifying the brakes then an additional valve may be required.
I know you worked your heart out and a$$ off on this, but I think there is still an issue with either a part or the way it was installed. Since both front brakes don't bite you would have the same error on both sides. Not likely. So it is more likely that the error is found at the master cylinder.
Is the brake pedal play properly adjusted?
If I understand this correctly the mastercylinder has 2 chambers, one for the front brakes and one for the rear brakes. Both chambers would have to be bled correctly.
Do you have ABS? If any air got into the ABS hydraulics you will have issues.
My Haynes manual for the Windstar says to open the bleeders and let the fluid flow for 5 minutes. Then follow with bleeding the system by pushing the pedal 25x for each wheel. And pushing/ releasing it slowly.
Good thing that brake fluid is cheap.

 

I have to think back on some of this.
I don't remember if the master cylinder is perfectly level where it is mounted on the booster.
If it is not-- most of the time the front of the master cylinder is higher than the rear and this allows any air trapped in the master cylinder to remain there unless the vehicle is jacked up from the rear and the master cylinder is now level at which point if you depress the brake pedal about 1 inch and release it slowly several times and repeat the procedure . this will have the same effect as bench bleeding it, but with the system closed. Many times I have been fooled into thinking all the air was out only to find it wasn't. If you have a vacuum pump with the clear vinyl tubing connected to the bleeder fitting you will see air moving back and forth in the tubing and that can tell you if all the air is really out.

 

Does your pedal go to the floor?
Bob

 

I bench bled the hell out of the master until no air bubbles came out. I'll try the letting the bleed for 5 mins. Yes the pedal goes right to the floor with mo resistance

 

I had an issue similar to this with an older ford, turned out to be the eh valve if you have one it will be located on the frame rail,under the drivers seat. Looks similar to a mini master cylinder.worth checking out. If you plug both ports on the master cylinder and then have a hard pedal the issue is not bleeding or a master cylinder.
Bob

 

When I plugged the front brakes of the master I have a pedal when I plug the rear and only have front hooked up or have both hooked up I have no pedal. That valve connected to the frame only hooks to the back brakes and the front brakes are the issue.

 

Can you do this?
With everything connected and full of fluid, have someone step on the brake pedal and watch the front calipers to see if the pistons come out far enough to lock the rotors.
Then release the pedal and watch the amount of movement the inner pads retract. It should be very little.Have someone pump that pedal and watch them again closely. If the caliper pistons come out enough to lock the rotors after pumping that pedal there has to be air in the lines. How are you bleeding them? Are you using 2 people to do this? Many times guys say they have bled the air out ,but they are doing something incorrectly. No offense intended, but we are at the point where we can't take anything for granted. Have you had one person in the car holding the pedal down while you open the caliper bleeder fitting and closing it before they let the pedal up? Not being there, do you have the bleeder fittings on the upper part of the caliper so the air can rise to the top and be expelled when pressure is applied at the master cylinder?
If the brakes worked fine before the parts were changed then there is something wrong caused by the parts or the procedure.
You have done the smart thing by asking for help. Even the experts ask for help when they have a problem.