Brake bleeding help

[junebug]

Just installed new W/H front disc setup with prop valve. Question is why can’t we can’t get any fluid out of the back bleeders? Is the prop valve closing off the back circuit? If so how can it be set to pass enough fluid for initial bleed setup?


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[billh1289]

Did you do the initial bleed with the plastic proportioning valve tool installed? If not might have to reset

 

[DirtDonk]

The prop valve should not block fluid flow to the rear completely. But a defective one might.
Then again, so can other things.
Are the hard and soft lines new too?

Seems like a good time to revisit the old “do it, or don’t it” discussion on whether or not an H-block or a combination valve actually blocks flow to the side that the shuttle valve slides to.
Paging James Roney. Do you happen to already know, or if not do you have any of those in your piles of spare parts you could check the function of?

 

[junebug]

There wasn’t a tool included in the kit… please tell me it’s something that can be sourced locally… tired of paying for fright on stuff


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[DirtDonk]

You’re mean, like tired of paying $15 to ship a $5 tool? That kind of tired?

They are not unique to just Broncos, so I would hope that somebody somewhere carries them. I’m just not sure what type of local company would be the most likely. Not the typical thing founded a NAPA store I don’t think.
Many sources these days, but most are online which would often need to include shipping.

 

[DirtDonk]

You can probably make your own with a bolt and a grinder.

 

[junebug]

I just found a great video on YouTube. I actually learned something….It’s not a prop valve but a combo valve. Sure enough the back circuit is blocked off during bleeding without the tool. Shocked it’s not included with the valve…guess I have to get the wife to order one on Amazon


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[DirtDonk]

Never used the tool and never had the fluid blocked to the rear. Got a link to the video by any chance?

Paul

 

[junebug]

No prob DD… see below. Always nice to see how stuff works

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[DirtDonk]

Thanks!
One reason I specifically asked for James Roney by name is that I know that at one time he had multiple examples of factory Ford combination valves for different vehicles.
They all looked similar, with some being physically identical to what you'd see on a '76 or '77 Bronco, but with different port sizes. So one designed for one vehicle would not retrofit (easily at any rate) to another vehicle.
Hopefully he still has some of those, and maybe even an example of the aftermarket ones like in the MPB video.
I'd expect anyone from MPB to know the details, but wonder if theirs are the same as those from the factory in that final function of blocking fluid movement entirely.

And one more thing that I "think" is true, is that these blocks-of-brass designs are copies of what GM used for years. And what I also have heard more recently what Ford used at some point as well. Never seen a machined block on a Ford myself though. Just the rough cast pieces like came on Broncos.

Paul