combo valve

Discussion in 'General IH Tech' started by Greg Cejka, Nov 12, 2019.


  1. Greg Cejka

    Greg Cejka Farmall Cub

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    I converted to rear discs on my scout ii and upgraded to the vet master cylinder. I have bled all the brakes and got it so fluid is coming, out but only have rear caliper engagement. My question is, I am not getting any front brake pressure, what could it be? my first thought is the combo valve so i watched it while Tom was operating the peddle and saw that little button going in and out. is it supposed to do that? I have the vavle off my other scout that I can try but dont know if its worth it since both were disk drum and the new set up is disc disc. any thought or advice would be greatly appreciated.
     
  2. Ron A

    Ron A High Wheeler

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    I have a Vet Master and combo on my 1961 C10. Nothing really special about it. Metering valve (in the combo valve) would be what controls fluid to the front brakes, assuming it is getting fluid from the master. If you can verify you have fluid flow from the master (you did bench bleed it?), then check for flow after the combo to the calipers, then check for flow at the calipers through the bleeder. Probably the combo, but you really need to go one step at a time to diagnose it before you throw parts at it. Here is a video on combo valve function that might help.

     
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  3. Greg Cejka

    Greg Cejka Farmall Cub

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    Thanks Ron. I did watch that exact video trying to figure this out.
    I did bench bleed the master. There is fluid coming out of the calipers both with no brake pressure and when the brakes are applied so they have been bled properly.
    so if I'm reading your post correctly it has to be a bad combo valve correct? not just an improper spring rate because of a change in the kind of brake I put out back.
     
  4. Ron A

    Ron A High Wheeler

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    I would think there is something wrong with the combo metering valve.
     

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