1992 F-350 Spongey Brakes

[ohpd03]

I have a 1992 Ford F-350 diesel. When the brake pedal is depressed it slowing goes to the floor. Changed master cylinders(twice) , bled all 4 wheels, and a new front caliper. Any suggestions? Thanks

[big white bufflo]

are the backing plates on the rear brakes dry you could have a wheel cyl gone bad or try adjusting the rear brakes too

[ohpd03]

Also just put a brake booster on. same thing.

[sum1_forgotten]

check your rear brake drums for cracks. if they are cracked to the point they are seperating it would cause this. also make sure none of the brake hoses are kinked. I had this problem on my 92 f150 when i let someone else do my front brakes and they put the caliper on and somehow had twisted it. reinstalled the caliper correctly and that solved it.

[sum1_forgotten]

if the adjusters are backwards on the rear brakes they will adjust for a moment and back off at the same time. make sure the keeper arm is snug against the adjustment wheel and that the adjusters werent put in backwards.

[mechhound]

Originally Posted by ohpd03

I have a 1992 Ford F-350 diesel. When the brake pedal is depressed it slowing goes to the floor. Changed master cylinders(twice) , bled all 4 wheels, and a new front caliper. Any suggestions? Thanks

I'm not sure exactly what you're doing but. If you sit and bear down on the brake pedal while stopped with the engine running, most Fords of this vintage, the brake pedal will slowly go to the floor or almost to the floor. Every Ford I have of this vintage does it. I didn't realize this until I read it on a forum and tried it.

I'm not there to observe how yours is acting, so I can't say if it's normal for a Ford or not.

[RahX]

X2
If it stops normally and won't go to the floor unless you make it there is a good chance there is nothing wrong. If it goes to the floor and you have to work to keep it stopped then it is something to worry about.