Hello All,

First I appreciate any help given.

after digging around these threads and others I have some questions and need some advice.

What I have:
71 F100 with what I'm told has brakes from a 81 F150. Got it from a guy who had it for 3 months then had financial difficulties. he bought it from the guy who supposedly installed the motor, trans, and front disc brakes from a junk yard F150.

Issue/Problems:
The brakes are almost non existent and the petal goes all the way to the floor. feels mushy and scary

What I have done (before I started reading through the threads):
I have replaced all the Rear Drum brake components, drum, pads, springs. I have replaced the booster and master. Flushed the lines and bled the brake lines.

Questions:
with everything replaced would this issue be because he did not install the Master and P-Valve from the F150?

This Truck is "New" to me and I would love to drive it but cant until I have this dangerous problem resolved.

Thanks again everyone!

 

Ug,

I feel your pain. Been there. If the pedal is going all the way down with nothing, then it's gotta be a leak or air in the system. You certainly would know if there was a fluid leak, as it makes a mess pretty quick...or at least overnight.
Air in system can be a pain to get out. Did you have a Buddy helping you bleed the brakes? I always use a trusted friend before we start drinking to bleed the brakes. Re check the Booster and Master especially since you replaced them.
Keep at it but go slow and methodical. I know it's the last you want to hear too.

 

Yep, had help. flushed all the old fluid, filled it up and bled them 3 times until it was nothing but fluid. may be some still in there but I don't think there is.

 

If you have a drum master , It will not push enough fluid for disc brakes ....

 

So could I go to A-zone and buy a 73+ Master and fix the problem? do I need that P-Valve too?

 

Not sure .... Hope someone else chimes in soon ... !

 

Me too! thanks anyway!

 

Yes you need the prop valve. The PO ran the newer lines to what? They are supposed to be M.C to prop valve and then fore and aft. Yes you need a disc brake M/C. Look top of this page. Where it says "READ FIRST". HioSilver did an excellent compilation of info. Read up on various disc brake and adding power brake threads. Then get what you can locally per which avenue you choose.

 

I think for one thing you have the wrong M/cylinder.
I was given a m/c that had 1.1/4 for disc brakes with a large reservoirs.
the M/C line holes fitting on the left.

I had the rear brakes adjusted up pretty tight and still had about 1/2 pedal that was also kind of mushy also.

Well after kicking this around and not content with the soft 1/2 pedal had enough and order a new one from rock auto $50 bucks. The one, I ordered was a m/c for a 1976 with 1.1/8" cyl bore a little smaller reservoir wells.

I got it installed and worked out the air slowly just with the pedal having the brake lines on just a few threads kept working it slow until no air,then tighten up the lines and checked the pedal and could not push the pedal more then just the play in the push rod going into the M/c with engine running. It was a now rock hard brake pedal now and needed to backed off the rear brakes.

That dang m/c was the main problem that caused the mushy 1/2 pedal.

Now, I was still using the oem P-valve for the 4 wheel drum brakes.

Its now had a great pedal but hard to stop due to the P valve and rear brake shoes not seated yet. I added a adjustable P-valve to the rear brakes only and now stops much better plus still had to let the rear & front pads & shoes seat...


The new m/c from rock auto had a funky lid (china) air breathers that caused it to leak fluid when the reservoirs was even 3/4 full.

It was a **** poor way they did it. I even punched a air hole in the lid and flattened out what was there breather design by them and it still leaked some.

Geez, I even tighten up the lid clamp and still leaked.

Okay so got it fixed the leaky m/c lid with a cheap chrome lid, I got at the good guys car show that looked more like an oem one..

No leaks and good had pedal that now stops great..

Here where I placed the p valve in the rears
orich

 

thank you all, your posts have helped me quite a bit!