Okay so ive never had to go this far into brakes befor but i need help. I recently replaced my brake master cylinder and the side for the front breaks wont bleed could it be my booster or am i thinking to far into this? My truck is an 86 f150

 

Did you bench bleed the MC before installing?

 

How does one bench bleed

 

To bench bleed the MC:

1) Secure MC in a vise
2) Fill front and rear chamber of MC with brake fluid
3) Move the MC piston back and forth in the bore and watch for bubbles in the brake fluid
4) Keep moving the MC piston until bubbles no longer appear
5) Top off the MC with brake fluid and install

I've had mixed results bench bleeding MCs. In fact, I replaced the MC on my 86 f250 and bled the brakes without bench bleeding the MC. The truck stops fine. Of course, I've NEVER had luck with pressure bleeders or hand held bleeders. IMHO, the only way to effectively bleed brakes is to have a buddy pump the brakes and hold the pedal down when you crack the bleed screw. It's messy but I'm always successful when I bleed brakes that way.

 

Ideally, you want to thread into the ports some lines that feedback into the master cylinder the hoses are held in place with a couple of clips. There are lots of cheap kits available.
As an example
Once the lines are installed drop the master cylinder in a vice to hold it, and it is just a matter of pumping the master cylinder plunger with drift or screwdriver or whatever until no more air is seen coming from the return lines. I use clear return lines instead of the black ones shown in the kit. You can install the master cylinder and use the brake pedal to do the same thing but ideally, you need a helper to pump the brakes so you can keep an eye on what's going in the master cylinder.
Once the bleeding is done you can not let the master cylinder drain it's self empty. If you used a helper and installed the master cylinder then it is easy, just remove the bleed return line and install the brake line. If you bench bled it then you need to install the master cylinder making sure it does not drain empty. in the process. I just clamp the lines off with a couple of small hose pinch clamps (Clothes pegs will work in a pinch) and put the lid on the MC and install.
Without bench bleeding, it is nearly impossible to get all the air out the MC.
As a note some MC's have a bleed screw, ones withe bleed screw need bench-bled then bled out the bleed screw.

 

Most of the kits I have bought recently come with plastic plugs. You pick the correct threads and screw the plugs in tight to block the MC ports, and then you do the same routine, pushing the plunger. You can see the air come out of the compensation ports in the bottom of the reservoirs. As the air comes out, the plunger stroke gets shorter and shorter. You have to keep going and going doing it this way, sometimes I have plunged it up to 30 times. But once you are done, the plunger will not budge. That's the indicator that ALL of the air is out. You can also see why doing it on the car would be futile.

 

the brakes dont need bleed tho thats the thing ive bleed them the issue is my front side of the mc wont bleed causeing my front brakes to not work causeing me to not drive my baby

 

And this why you need to bench bleed the master cylinder. The rear bled out and it now actuating the rear brakes and lockin up the plunger and the plunger will not depress any further to bleed out the front brakes you could try gravity bleeding the fronts but really you should bench bleed the MC

 

I just did the master on my 81 F100 and it came with the bench bleeder kit (hoses & clip to keep it in the master below fluid level.
After the bench bleeding plug the rubber plugs back in the ports to keep the fluid from dripping out.

Now after bench bleeding I could not get a good pedal.
I did the helper bleeding in the truck and that still did not help the pedal. Helper may have been part of the issue?

I built a home made pressure bleeding setup and after a few adjustments I was able to use it.
I can say I did not get a lot of air out (the rear) but enough that the pedal is now normal.
With out the pressure bleeder used on the truck I don't think I could have gotten all the air out.

BTW my system was completely drained as I did a full rebuild of the truck & brake system.
Dave ----

 

I'm with Dave on this one. For whatever reason, these trucks sometimes resist the typical Michael Jackson (man and a boy) bleeding method with a helper in the cab. A full external pressure bleed seems to be the only fix when other methods fail.

Gory details of an epic battle here:

https://www.ford-trucks.com/forums/1...-now-what.html

 

A lot of time that is the result of not holding out or pushing in the bleeder valve on the proportioning valve.

 

Let it be known I tried that on mine and that part did not move at all. Not out or in.
Dave ----

 

thank you everyone today is my day off so im gonna try it and see what happens if it works ill let you all know

 

Time for a new proportioning valve or pull yours apart for a rebuild then as the stem type should move easily.

 

I have another from my parts truck I may check out but I have brakes, pedal feels good and firm and being I got other "bugs" to fix it will stay as is for now.
Besides I don't need a stinking light to tell me I lost the brakes the damn pedal goes to the floor!
And yes I know it "portions" the pressure front to rear but being old school I can feel when the brakes are going to lock up and if you drive looking down the road you are never in that position.
Dave ----