Brake Proportioning Valve

Discussion in 'Classic Mustang Specific Tech' started by candphall, May 30, 2013.

  1. What is the easiest way to center the valve after bleeding. 69 discs front drums rear.
  2. You don`t center the valve, it does it automatically if its working correctly. And it should be about 60 to 70% up front, the rest in back. 50/50 setting would be a wreck in a hard corner. I had to put a residual pressure valve in line to my back drum brakes to get them to work right. this link may not be the exact one you need, but I do remember mine was a 10 lb pressure valve and it was red, so this might be it. I`d read up on it a little bit first if I were you.
  3. there is a tool that holds the valve centered while you bleed the brakes .
    the light switch unscrews an the tool screws in its place .once brakes are bled remove the tool and replace the light. you can recenter the valve by opening the oposite end brake bleeder of the direction you want the valve to go.two people would help. gently step on the pedal and check the valve through the brake light warning switch opening until you see the notch in the plunger , close the bleeders and replace the switch. it sometimes takes a few try's
  4. Thanks horse sense
  5. Thank goodness we have experts around to keep us in line, thanks horsesense.
  6. well the trick is getting the valve centered .it usualy doesnt want to stop where you need it to. if you can see the notch at all insert the tool and thread it in slowly and some times it will center the piston.if not some one steping on the pedal very gently can move the piston enough to get the tool to center in the v shaped notch . the tool is a thumb nut with a pin on the end that dropes into the v notch to hold it solid while you bleed the brakes
  7. Looks like this:

    Attached Files:

  8. Any idea where I can pickup one of those tools
  9. possibly Auto Zone or O'Reilliys?
  10. Thanks I got on on the way. It's funny I've been bleeding brakes forever and have never known about this device.
    Thanks all
  11. I also find it interesting that it is not mentioned in the service manual.
  12. my brother in law gave me one about 10 years ago when he heard me cussing at my 69. i cant find it ,looks like i will need a new one also.
  13. I had one of these valves get stuck to 1 side and I've never been able to unstick it. I'm shocked I didn't know about this tool.... I'm a massive tool whore.....

    Anyways, if the pin gets stuck you can always throw the thing away and replace it with a union for the rear circuit and a T for the front. You should plumb in a proportioning valve for the rear if you do that however...

    I'm going to rewire the brake warning light to be used as a parking brake warning light on mine.
  14. i have taken them apart and rebuilt them you just have to use the correct o rings. you can use an adjustable proportioning valve but the purpose of the origional valve is if you loose front or rear brakes the valve will trip and shut off the leak so you will either have front brakes or rear brakes / what ever end isn't leaking.
  15. horse sence
    Do you have a source for the o rings. I rebuilt mine last week and am not sure the orings I used are for use with brake fluid. I used oring from one of those asortments from ebay. They are green rubber. A proper size would be good if you have it.
    I havent bled the system yet.
  16. i got them from a hydrolic shop. i dont remember the size. they have to be chemical resistant though
  17. My valve was stuck, I removed the nut on one end and was able to freethe valve by inserting a small pin and tapping with a hammer. I got tool recommended above and will use it to keep the valve centered during bleeding. We will see how it works.
  18. i found for the best results to pump up the brakes and have some one crack all four bleeders /with the tool in place. when the pedal dropes all the way tighten all four bleeders and release the pedal it will equalize the presure on both ends of the valve then remove the tool . the valve should stay centered .
  19. If you have a stock combination valve (valve for discs front/drums rear), you do not want to add a separate, manually-adjustable proportioning valve in line to the rear brakes without first removing the proportioning valve, valve spring and valve seals from the original combination valve.

    If you don't remove the stock proportioning valve components, you will have two proportioning valves competing against each other.

    You can purchase the differential pressure valve spool lock tool from Muscle Car Research. They also offer many of the internal springs and seals to rebuild stock Ford (drum/drum) pressure differential valves and (disc/drum) combination valves.