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Brake proportioning valve

Discussion in '80-Series Tech' started by Photo_Cruiser, Apr 30, 2003.

  1. Photo_Cruiser

    Photo_Cruiser

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    So, after installing the 2.5" OME springs and shocks, heavy load, with no accessories at this point, is adjusting the rear brake valve mandatory? According to Acme, since I don't have a pressure gauge, it's trial and error. Move it from 90mm to 100mm, is my starting guess..any comments or suggestions.

    If I need to adjust it further, my clue would be soft/weak rear brakes?

    One upgrade at a time.......
     
  2. Beowulf

    Beowulf

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    Yes, you should adjust your LSPV. 100mm is about 4" which is WAY too much adjustment.

    The easiest adjustment is to lower the bracket where the LSPV mounts to the frame. For a 50mm OME lift you will lower this bracket approx 1/4".

    -B-
     
  3. landtank

    landtank SILVER Star

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    Yes you need to adjust it right away. People have had serious problems by not doing so. Don't worry about HOW to do it as the new spring rate basically puts the valve out of sync with the weight/compression ratio, but do something to regain the braking of the rear.

    Rick

    -B- cocconut scent? How Gay! Is that a candle you burn while driving?
     
  4. Hltoppr

    Hltoppr SILVER Star

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    Easy there Landtank... I just happen to be quite the Parrothead, and Coconut scent is perfectly acceptable... as is the Vanilla I currently have. Of course, at some time my cruiser may be called upon to transport a 901 out of the woods, which as some will know, don't smell so good, I have to be prepared... :eek:

    Back on topic. I just adjusted mine all the way, and so far so good.

    -H-
     
  5. Photo_Cruiser

    Photo_Cruiser

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    When I say 100mm, stock is 90mm, from center top shackle to center bottom shackle, so I was going to lower it 10mm, which is about a 1/2 inch. I'll start at 1/4" and see how that goes. Any comments on how you can tell if it is incorrect??

    I'm going off of the Acme directions, since slee's just says 'adjust it'.

    Lift aint on yet, I'm just getting my ducks in a row. all the goodies are piled in the garage.
     
  6. Photoman

    Photoman SILVER Star

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    For a test you can drive slowly on a sand, gravel, or dirt area and jam the brakes on. Get out and measure or look at the skid marks to see if your front or rear is sliding more than the other - then readjust.
    Bill
     
  7. landtank

    landtank SILVER Star

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    Photo_Cruiser the skid mark might not work for you if you have ABS as they won't lock up. What I did was to measure the height before the lift and then after the lift with the usual cargo on board. I then bent the arm so to eliminate the lift. Same braking before and after with the same weight.

    As for scent I'd say Burrito about a hour and a half later.
     
  8. upcruiser

    upcruiser

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    If you don't have the valve adjusted enough, you will know the difference. I took my truck for a spin after throwing the lift on, just to see how bad the brakes where, and they felt like they had about half of their braking effectiveness. :eek:

    I too just bent the arm to make up the difference.
     
  9. Beowulf

    Beowulf

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    As -H- said, I just adjusted mine all the way, and so far so good. (Me too.)

    I have read several places, including the FSM, that says *never* bend the arm. If you can adjust the LSPV mounting bracket then do it that way.

    -B-
     
  10. landtank

    landtank SILVER Star

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    I first tried to adjust the valve but the first bolt broke off and figured it was there to stay. If you do decide to bend the arm besure to bend it outside the valve area. It is important not to change the relationship of the pivot point and how the arm interfaces with the valve in that area.
     
  11. BigMac

    BigMac SILVER Star

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    When I stopped in at Sllee's a couple of weeks ago, Ben told me to lower the valve body 5 mm for the 2.5 OME lift. He also cautioned that the mounting bolts are frequently corroded on tight.
     
  12. Photo_Cruiser

    Photo_Cruiser

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    OK
    That's what I was looking for, 5mm, from the dude at Slee. I also read never to bend it, but I'm sure that works fine. Several ways to skin the cat. I will also use my center dif lock switch trick to disable ABS and try the skid thing as well. Thanks for all of the help.


    Jeff