I recently inherited my father's 73 F-100 when he purchased his next 'new truck' '99 F-350 V10. My first project was to attempt to get decent brakes working on it. Pads, MC, booster, nunerous bleedings later and I still have poor control over the brakes. Soft pedal, then grabs throwing all inside cab into the dash and windshield. Any suggestions? I do some of my own work but so far have 'trusted' a local truck shop to do this work and associated warranty work, no the tech is hiding when he sees me coming. Any points in the right direction will be GREATLY appreciated. The tech mentioned that the pedal to MC mechanism is a scissor type and not a std. link rod type, could this be a problem?

 

Does your truck have front disc, you may have calipers that are sticking.

First describe where the pedal is, high low meduim, next tell us what it does, are you pressing harder or not and when do the brakes grab. It almost sounds like the calipers are sticking and causing the front pads not to grab.

the other problem might be the brake proportion valve, this is where the two lines go into four lines. this may be bad and causing your problem.

Let us know what you find


Dave

 

Yes, front disc brakes. Pedal is EXTREMELY low, almost to the floor with little to no braking until all of a sudden....WOOOOOOOO....they come on in full force to an immediate squeeling halt. Feels like all front braking and no rear. I have taken it back in numerous times for the m to be adjusted only to drive off with low pedal again but a 'slight' change in the response. Last time they tool booster off and adjusted the rod, franlky I do not think they have 'old car' experience.
Lastly, it does not take much pressure at all to apply the brakes, the pedal just seems to go to the floor and then you are thrown into the dash. Pumping does not seem to help.
>

 

Hey Andy,you need to rework your back brakes!The problem is you have to much clearance between the shoes and the drum for the master cyl. to take up,and yes,that's why they kick in all of a sudden,once everything has expanded to fit.I'm sure you will need new wheel cylinders back there also because while that old, they are either rusted shut or leaking like a faucet.Besides all of that,Deleontow has a good point about the proportion valve,try cracking a front bleeder while fully bleeding the back,it works every time for me to reset the p-valve.At last,you could have gotten a defective m-cyl,or, the wrong one{front brake line is usually at the back of the m-cyl,but not always}!
Phillip

 

I'll try these routes and see where they lead me. I've gotten more info in 3 hours than I've been able to gather in 2 mos. here and there.
Sorry for starting the 2nd thread by mistake, I'm new at this. A