Hey folks, need some help. Yesterday I replaced all my brake lines, and put a new master cylinder and booster on the truck. I have a manual pump "ope man bleeder" The rear drums bleed out fine. However when I loosened the bleeder screws on the front drums I could not get any flow from either side.

I did get a little bit of left over fluid that was left in the rubber lines but nothing out of the master cylinder.

I bench bled the master cylinder according to the instructions that came with it. Everything was going smoothly until I tried to bleed the front drums.

Any ideas on what could be causing that? The pedal is tight there is just no fluid flowing

All I can think is that something is blocking the flow?

Thanks!

 

the bleeders could be clogged , take them out and soak in some solvent then clean holes with an old tooth brush and paper clip .
you can always try the old 2 person way

 

did you replace the rubber lines? they could be collapsed internally blocking the flow.
have you tried taking the line off the wheel cylinder and see it fluid flows? If it flows fine from the end of the line that goes into the wheel cylinder then take a look at the wheel cylinder and its bleeder.

 

I checked the bleeders. They did produce a little fluid from the rubber lines that were left on. The rubber lines that run to the drums are new. Pulled the rear line off the master cylinder to check if there was a blockage there but nothing.

I've had the wife sit in the cab and slow pump the brakes but still not getting any juice. The manual for the cylinder states that if the pedal is firm it's not the master cylinder...

I'm at a loss. This should be really simple...

 

proportioning valve ?
like said pull a FRONT hose and step on pedal , if no fluid then problem is closer to master cylinder .

 

If it's a drum/drum setup, there is no proportioning valve, just a distribution block. There may be a blockage in the distribution block, allowing fluid to the rear brakes, but not the front. Pull the lines to the front brakes and see if you get anything out of the block.

 

Well, I went all the way back to the master cylinder. Tried to pull a vac through the line coming straight out of the master and nothing. Took the master cyl back off and went through the bench bleed process again. Still nothing. Even put the vac straight on the port coming out of the master cylinder and nothing... Took the vac hose off and left the master cylinder bleeder plug out and pressed through the cycle with a wood dowel.. nothing flows... so I figure I just got a bad one. Shame too. I ordered it from Macs... looks like the old classic master cylinders. had it painted and all prettied up and no joy...

 

Look at far right center of pic below 2074 distribution block for 2B257

C8TZ-2B257-D .. Brake Pressure Differential Valve. Some people call this a proportioning valve, but Ford never did, used this same description for drum and disc brakes.

Applications: 1968/72 F100/250 2WD & F350 (except 1968/72 F250 2WD & F350 with optional disc brakes that use C8TZ-2B257-G).

 

could you try to take a turkey baseter and rubber hose and push fluid from the bleeder to the master? it might clear a blockage.

 

A turkey baster... that's a great idea.. did not think about trying to back it up.

I'll give that a shot this evening.

 

Ok. I posted here that I couldn't find a wrench to get on my bleeder screw. I figured it out and I feel like a moron for my oversight. Thanks for trying to help.

 

Edit: ....never mind. I just noticed this is an old thread.