My 99 f350 has been dragging the brakes for sometime now. I have replaced calipers, hoses power steering pump, master cylinder 3 times and hyroboost 3 times, nothing obstructing the pedal and I have bypassed the proportioning valve/RABS cant get a clear answer to which one I have. It's a late 99 with 334k on her and I'm about to blow the attention where up

 

 

All 5 hoses have been replaced including the rear center. Everything has been flushed installed and bleed out correctly numerous time after reading for countless hours on all of this and still cant find a solution

 

 

didnt see any mention of pads being replaced... was this ever done?? if so was it done because of the issue or was it done before with the symptoms showing up afterwards?? if they were changed what brand and type were used?

 

Do you have a warped rotor ?

 

The rear pads I replaced about 5 months ago and the front was about a year ago with duralast. I would believe it's the brakes due to the fact the my truck is covered in brake dust, the front pads only have about 25% left and the rear is at about 50%, and there have been times on hot day they would be smoking, and I know when they start to drag the truck becomes squirrelly. As of last night I have came to the conclusion it's the hydra boost again because I can feel it in the pedal and my power steering pump is whining like I am constantly holding my steering wheel all the way over, I get to do the warranty work on that. Could my hydra boost be going out because of the fluid I'm running through it, I used valvoline dex/merc

 

Duralast pads are good... i use them on mine.. very grippy.. I tried ceramics once from a different band and had nothing but problems from the day they went on... Switched back to the duralast semi's and problems went away instantly... it was a night and day difference... (being able to stop is a wonderful thing)..

have you thought of trying to adjust the actuator pin behind the master cyl? seen several threads on here that theres a ball on the end of that shaft that is adjustable.. usually theyre slacked off and need adjusted out.. but could be yours is adjusted too far out and keeping the brakes on enough to drag..

 

I took the master cylinder off to check the push rod and there is no adjustment on it. I used some washers between the hydro boost and mc and the truck felt great for about 20 miles then went back to ****. I'm thinking of trying a hydro for an 05 out, they look similar, I will compare the two tomorrow at the parts store as of right now I only know of the bolts being of different size but that shouldn't be a big deal everything else looks correct same ports same side. I could probably do 05 hydro and mc and have the pressure lines made and make the brake lines myself. I will let you guys know what I decide and what happens.

 

I have not been to bed yet so please excuse the spelling and punctuation errors. That is if spell check does not get them.

The pads that you took off was the wear even on each pair of inboard and outboard or did you
have any that the in or out was a lot thicker? One quick thing to check are the glide pins and
cleaned all the points where the pads come in contact with the anchor bracket and installed
the guides that the go between the pas and the bracket.

 

I am with Sean, I don't see any mention about the hardware that the calipers mount to. That is usually a problem with sticky or uneven wear of the pads. Sometimes greasing will do.

I would suspect with the amount of miles yours are just wore out.

 

I have all new guide pins and hardware and everything was greased with ceramic grease. The ware has been even.

 

Do you have a non-contact thermometer? I would go out for a drive and pull off
in a safe spot or parking lot and get out ahd see what each wheel is at for the
temp. If you have one that is hotter than the rest then that gives you a place
to start looking. If they all come out to about the same temp. The only thing I
would think at this point is you have something holding pressure in the system.

Just for giggles. What happens if you go out for a drive and come back home
and crack open a bleeder first thing. Does is just dribble or squirt? Mind you
this has to be checked right when you pull in to see if you have pressure in
the system that bleeds off as it sits. You will have to do this to each circuit.

 

I have checked the temp and all are reading just about the same. I can shut the truck down and start it right back up and they dont drag for about a mile the longer I run it the more and more pressure they apply but as soon I I turn her off the pressure goes away

 

I think I have an older Ford service manual that might cover what you have
but will need the full details so I can look and see if I have it. So far I know
that it is a 99 f350 but what engine and options do you have. I will get back
to you on it latertonight once I have had time to do some reading.

You said you already replaced the hydroboost and the MS and calipers.
Not too much left to make it a new system.