working on my 89 f-350 box trk. replaced , master cylnder, all brake lines rubber and steel, new fittings, power booster, calpers,wheel cylinders, shoes , pads, everything has been replaced, master cylnder twice,, just because we thought it might be the problem... no leaks anywhere,,,

problem: when bleeding , after all air has been visably let out of the lines,, holding the brake pedle its fades to floor. 1st hit to pedle right to floor,, pump peddle a few times build up , but when you hold it fads to floor.. gone threw over 2 gallons of break fluid.... anyong have any idea wtf the problem is? what i mean by 2gallons of brake fuild is what we blead out of the lines,,, no air ,, all fuild,,,

also blocked off right ft wheel and left ft wheel no change,, but when blocked off the back lines , then the pedle stays where it should be ,, replaced wheel cylnders and fittings and break line again to the back ,, still same thing pedle 1st hit gos to the floor, when u pump it up and hold it ,, it fades to floor

 

Could you please tell me exactly how you are bleeding the rear cylinders. Don't assume anything because it's very important that you describe every step you are doing. I will be waiting for your reply.

 

R/r l/r pump 3 hold

 

stick a small, see thru, plastic hose on the bleeder nut. and submerge other end in glass jar with some fluid in it . needs to be about three feet long to set jar on the floor. this way you can see the air bubbles and also not waste any fluid....sorry dont know whats wrong with your hydro. and what happened? and by the way where did those eight cans of brake fluid end up?

 

Every time I used the plastic hose method , it sucked air right back into the system when releasing the pedal. That's why I asked that you describe the method you are using to bleed the system. Use two people one at the bleeder fitting and one in the vehicle. That's why you don't have this problem when using a pressure bleeder. And as always close the fitting before letting the pedal back up.

 

I mentioned submerging the open end of the tube ...if there is any back draw it pulls only fluid not air...

 

If you are pulling the same fluid in that you are pushing out , you're not getting the air back in the line out of there. The theory of using the tube has let me down once or twice now I just use the old method of pump it open the bleeder, what comes out comes out,
when it goes to the floor close the bleeder screw and start over again. Without a pressure bleeder, that is the only sure way to get all the air out ,And that depends on the ABS system too.