i just picked up a e250... cheep, i knew it had brake problems when i bought it, but this one is confusing me, i was told by the owner that the wheel cylinders were bad, the bleeder was broken and they could not be blead. he was right, of course, in the process of changing them, i had to cut the lines and replace the lines, all is fine with them, but my pedel is still soft, you can pump it up somewhat and it gets firmer (van off) let it sit for 2 seconds and woosh right to the floor, im thinking Master Cylinder, but ive seen posts about this rabs valve, which do you beleive, i know Master Cylinders usealy fade when you hold pressure on them when they are bad, this pedel goes straight down.
when i test drove the van, the bakes dropped straight down to the floor, press a little more and the van would stop. i agreed the air in the line could do it, the air is gone, the back brakes blead like a normal brake system any help would be great. thanks dennis

 

You may have a leaking RABS dump valve. Locate the valve(usually on the frame rail under the drivers foot. Identify which valve you have either square or round(most likely round) If it's square: Locate and remove the small rubber cover at the end of the RABS valve. Straighten a metal paper clip and insert it into the hole covered by the rubber cap until it bottoms out. While watching the paper clip have someone firmly apply the brake pedal. If the paper clip moves at all the dump valve check ball seat is leaking and you must replace the RABS valve. There also should not be any fluid at all that runs out when the rubber cap is removed. If you have the round valve(larger). Use a 1 1/4 box end wrench and remove the end cap from the valve. there is a spring under the cap but it doesnt have a great deal of pressure on it. You can easily control the end cap while removing it. Visually observe the piston inside the area covered by the cap or place your finger near the end of the piston( dont press on it). While having someone firmly apply the brakes check for any movement of the accumulator piston. If it moves at all the dump valve is leaking and you need a new RABS. No fluid should spill out when you take the cap of either. There is also a possibility that you wont have these access ports on your vehicle. Did the fromer owner replace the Master? If so did he bench bleed it? If he didnt that could also be the problem

 

i dont think the master has been changed, i suggested that it may be the master, he didnt say he changed it so, id say no its orginal, teh van does have 218,000 miles so i can be anything
ill check that rabs valve thanks for the help

 

Or try this: Clamp off the front and rear brake hoses to see if the pedal feels any better. If it does take off the clamps one at a time and see if the problem is at a particular wheel. If it doesnt feel any better with clamps on the master may be bad.

 

well i removed the lines from the MC and plugged them, still have fade, replaced the MC, still have fade. so i plugged the rear port again, and no fade, so i think im lucky enough to have 2 bad valves the MC and the Rabs, im gunna open the rabs and see if the piston moves now, i didnt befor ethe MC change. does the van have to be runnign, the battery is out of the van, is it possible the rabs valve is not working cause no poweR???
thanks again for your time, hopefully tomarrow ill check the rabs again, i may just bypass it, and be done with it, the van for the most part is empty, so abs would be nice.
thanks dennis

 

Have the truck running when you check the RABS. Another thing is these Fords can be bad about trapping air in the front calipers. Pump them up and take a hammer and tap around the caliper to dislodge air bubbles then bleed em. Make sure the calipers are not frozen also. Its probably the RABS. You wouldnt be the first person to remove it. I cant remember what they cost but there isnt much thats cheap from Ford anymore.

 

well, tryed running it, brakes go straight down, no rabs movement under the cab, i bought a line to go from the MC right past the rabs, gunna try that tomarrow, provided its not too hot. can the booster do this??? when my friend pushed on the brake pedal, the booster moved about abit?? thanks again for your time dennis

 

new find... front brakes, on both sides, the bottom slide pin is stuck, causing a very uneven wear on the inner pad and NO wear on the outer, hence theres lots of movement on calipers....LOTS, i hoping this extra travel is part of the problem, now i have to figure out how to get that lower pin out... or is it the upper pin shouldnt slide in and out? ahhhh ashes to ashes dust to dust if it wasnt for ford my tools would rust!

 

I dont know exactly which caliper you have but mine has 2 slide pins. The slides, pins, both top and bottom need to be lightly lubricated with SILICONE grease. Regular grease will destroy any rubber parts. My guess is thats the root of your problem,. My pins have hex heads on them. Yours may reguire a punch with long thin neck and take a hammer and tap tap them out. If there's any question as to the condition of the calipers just replace them. I just did mine at Autozone $53 a piece.

 

new find.... i im gunna give up on repair.... i cant even get the year right...turns out its a 1994 van, i bought a pair a drums on ebay for a 1996, the center hole is larger other then that i think thier teh same, so im gunna use em, now to work on the calipers which have some funky way of floating the pins. thanks again for your time

 

lower floating pins....no longer float they have permently docked into the spindle assmbly, off to the junk yard for new spindles

 

recap.... one lower pin removed, new silicone lubed pins installed, caliper floating, brake pedal is half mast... tomarrow i attact teh other pin. looks like rabs valve is good, thanks again for all your help dennis

 

Dennis, Maybe Im mistaken but i think you tested the RABS valve when the calipers were giving you trouble. Im thinking that maybe you didnt get a valid test of the RABS. If you can get the rotors and calipers OK and bled then maybe test the RABS again to be sure.

 

i tested the rabs when i had the bad master, i replaced that and still got the soft pedal. so i reblead everything, when doing the fronts, i realized the caliper moved ALOT, turns out on both calipers, the lower pin was completly seized, so the gap between the rotors and pads was big. i had quite a fight with a monkey wrench and a 10 foot long pipe to get those pins out.. we snapped on monkey wrench in the proccess.. into 3 pieces! we finally got them out, new pads, and now i have brakes
thanks again for all your help Dennis