Need Brake Help - 00 F250 4x4

[3g00clipse]

I have a ford f250 7.3. Last week i noticed that there was gunk and brake fluid all over the rear passenger side wheel and the brakes were REALLY soft but caught a little bit right before the floor. I changed the caliber and pads because it seemed like on of the pistons in the caliber was leaking. After I did this nothing got better just worse. The pedal goes all the way to the floor and I have no brakes at all, once in a while it will grab right befor the floor, but only the rear brakes will work. I have bled all the lines and there is no more air in them, I don't know what else to do so I am asking for some input on what to try next.

[3g00clipse]

It is a 2000 and a 4X4, forgot to mention that.

[RightWingNutJob]

The obvious questions.....Did you check all of the other brake hoses and brake lines to make sure that there's no other leak(s) in the system? Did you bleed all four brakes or just the rear ones? Are all of the brake bleed valves closed tightly? Do you have a brake bleed set up with a bottle so that air doesn't get sucked back in when you let up on the pedal and before you can close the bleed bolt?

While you were changing the calipers if the Brake Fluid level in the Master Cylinder resevoirs went down too low, air could've come in through the MasterCylinder. If it did, you probably now have air in the whole system and need to bleed all four brake calipers, and the ABS.

Even if the master cylinder didn't get too low, your truck has four wheel ABS - you probably still have air in the the brake system that doesn't get cleared out by old style brake system bleed of slowly depressing the brake pedal until the bubbles stop coming out. You may need to have the brakes bled with electronic tool that actuates the ABS controller while your bleeding the brakes and forces any other "hidden" air out.

One other thought - when I was young, an old timer told me to always put a brick or a piece of 2 by 4 under the pedal when bleeding the brakes. It prevents the pedal from going too far. Without any back pressure, you can damage the master cylinder because the bake pedal can travel beyond its normal range and breaks the diaphragms inside. (This applied to vehicles from 60's & 70's. Not sure about 21rst century ones, but I still do it just to be safe.)

That's a long shot - I'd double check for any leaks, buy more brake fluid, and bleed all four brakes more than once, and get the ABS bled too

[3g00clipse]

I bled all the brakes, that only thing that it might be is the abs. But the light isn't on, would air in the abs cause the light to come on?

[Rick M]

My guess is bad master cylinder due to over travel when the wheel caliper went out. As mentioned in a response above when those cups start traveling in areas not normally used it tends to damage them and you get bypass, blow back, leakage, whatever you want to call it. But, just a guess based on past experiences with older vehicles.