Brake diagram/question
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Brake diagram/question
1968 f250 rwd. Front has disc. Rear drums. I have no fluid at all at rear brakes. There is this t looking fitting on the rear axle that splits off to each wheel for the brakes. I havnt been able to break the lines loose there yet due to rust. By the way does anyone know the proper wrench size for the nuts on the brake lines?
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I don't know the size, but it seems they only used two different sizes over the years, so it should not be too hard to ascertain. Unless the corners are already buggered? Or even if they're good, but rusty enough it will be hard to tell for sure.
You could also try up from to see if fluid is stopping elsewhere. Does yours have a proportioning valve, or did it come with drums up front originally? Was yours the first year for disc brakes in the 2wd trucks? I forget.
Even if it's just a junction block in the shape of an "H" (called an "H-Block" oddly enough!
) it might have some crud in it that's blocking flow. Seen lots of proportioning valves fail on one circuit of the other. Not so much the H-blocks though.
Anyway, good luck with the rear fitting. If it's that bad, how is the actual rubber hose? Maybe now's the time to replace it. Hoses can collapse internally too, which is what you're about to find out I guess if you can get the lines apart.
Is yours held to the axle housing via the vent-bolt? If so might as well check the vent while you're at it. And if it happens to snap off while messing about with it, they're available new again. We have them in stock usually, assuming yours is the same size.
Paul
You could also try up from to see if fluid is stopping elsewhere. Does yours have a proportioning valve, or did it come with drums up front originally? Was yours the first year for disc brakes in the 2wd trucks? I forget.
Even if it's just a junction block in the shape of an "H" (called an "H-Block" oddly enough!
) it might have some crud in it that's blocking flow. Seen lots of proportioning valves fail on one circuit of the other. Not so much the H-blocks though.Anyway, good luck with the rear fitting. If it's that bad, how is the actual rubber hose? Maybe now's the time to replace it. Hoses can collapse internally too, which is what you're about to find out I guess if you can get the lines apart.
Is yours held to the axle housing via the vent-bolt? If so might as well check the vent while you're at it. And if it happens to snap off while messing about with it, they're available new again. We have them in stock usually, assuming yours is the same size.
Paul
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Trucks didn't get disc's until 73. Do you have a dual master? That proportioning valve should go away with the disc conversion and a manual proportioning valve should be used on the front only. Follow the lines down from the master and see if it's still hooked up to the original proportioning valve.
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I got this truck used. But I'm pretty sure the front disc were optional from the factory. Everything seems original. I did change the master cylinder which is dual by the way. Old one was dry and rusted inside. I've got fluid on the front brakes now just not the rear. There is this square looking thing on the rear axle that has a vent tube coming off it that was broke. And the 2 lines running to the rear wheels but not a drop of fluid.
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This is what the vent bolt would look like intact: https://www.wildhorses4x4.com/produc...co_Brake_Hoses
The block is usually a single piece with the flex hose from the frame molded into it. But they can vary.
Another way they can vary that we need to keep an eye on is that some Fords had their hard lines molded one-piece with the center block too, while others (most I think?) did have threaded ports in the block and separate hard lines with flared fittings and hex bezels attaching them to the block.
Sounded like yours has the hex heads, but Ford did use some that were not removable. I may be correct in saying that this was on later model 4wd trucks primarily, but it's still worth making sure that the hard lines are removable.
This would be the common design style (this is for a later 4wd) with separate components: https://www.wildhorses4x4.com/produc...sizebrakehoses
Sounds like that's more like what you have?
With a rusty master cylinder it's not hard to imagine that the hard lines got some rust in them as well, as could the rubber sections get clogged.
If it was my truck and I did not know how old the rubber lines were and I was replacing brake components, I would not leave any of the old rubber lines intact. Even the ones that seem to work ok now, such as the fronts.
Good luck.
Paul
The block is usually a single piece with the flex hose from the frame molded into it. But they can vary.
Another way they can vary that we need to keep an eye on is that some Fords had their hard lines molded one-piece with the center block too, while others (most I think?) did have threaded ports in the block and separate hard lines with flared fittings and hex bezels attaching them to the block.
Sounded like yours has the hex heads, but Ford did use some that were not removable. I may be correct in saying that this was on later model 4wd trucks primarily, but it's still worth making sure that the hard lines are removable.
This would be the common design style (this is for a later 4wd) with separate components: https://www.wildhorses4x4.com/produc...sizebrakehoses
Sounds like that's more like what you have?
With a rusty master cylinder it's not hard to imagine that the hard lines got some rust in them as well, as could the rubber sections get clogged.
If it was my truck and I did not know how old the rubber lines were and I was replacing brake components, I would not leave any of the old rubber lines intact. Even the ones that seem to work ok now, such as the fronts.
Good luck.
Paul
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