load sensing proportioning valve...

Discussion in '80-Series Tech' started by 4dmalamute, Jun 18, 2005.

  1. 4dmalamute

    4dmalamute

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    Ok, I have searched and searched and I am still at a loss. I just did the J spring lift all around with Mr Gasket up front. My question is, the load sensing proportioning valve..............I am confused, do I adjust it up, or lower it? Like I said, I read tons of stuff but then I just started getting confused over what to do. If anyone has some constructive help please post it up. thanks :beer:

    oh ya, not sure it matters but its a 1993 fzj80 and I am getting ready to put on the 315s.
     
  2. Rich

    Rich

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    Well, if it is the same as my 97 then you will need to lower the valve itself where it mounts to the frame. There is not enough adjustment at the axle end.

    The other alternative is to mod the threaded adjustment rod on the axle end, extending it enough (approximately the height of your lift) to get it back in range.

    You should review the factory manual and understand for yourself how it all works. That way you can make an informed decision for yourself how to best proceed.
     
  3. 4dmalamute

    4dmalamute

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    Thanks for the info Rich, as for the manual....no luck here, I do not have one as of yet. I keep searching and reading up on this but like I said, it seems every person has their own idea on what is the right and wrong way to do this. I know this is a simple mod that can be done easily but I am still not sure exactly what to do. Lame I know. :eek:
     
  4. Bryan E.

    Bryan E.

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  5. SR.GRINGO

    SR.GRINGO

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    lsvp

    On the valve end--the closest to the driver rear wheel you can adjust the valve down on the bracket--I adjusted the valve 1/4" down so it bottoms out. I run 315's and OME heavy lift with 2 trim packers per spring. When the rear seats are installed it is perfect along with my junk I carry in the back. With nothing in the back I need to lower the valve further but have not done so--I figure in a years time I will have a bumper back there solving the problem :)
     
  6. Rich

    Rich

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    Here are the choices as I see it:

    1) Just lower the valve a set amount according to somebody else's guess or experience and hope for the best. I didn't measure how much I lowered mine, and I am not willing to guess. Since you have J springs the adjustment will be more than for the smaller lifts. I don't know how much more.
    2) Do step 1 above, and then go test the brakes on a gravel road. You want the front brakes to always lock before the rear. If you have ABS, you need to first disable it to test. If the rear brakes lock first, move valve up. Your guess is as good as mine as to how much to move given your testing results.

    OR

    3) Raise the connection of the valve actuation rod on the rear threaded rod connected to the rear axle by the exact height of your lift. This will leave the valve proportioning as it was before the lift. Doing this requires extending the length of the threaded rod, as it comes from factory there is not enough adjustment.

    OR

    4) Buy a couple of brake pressure gauges and follow the factory procedure. Will cost you about 80 bucks for the gauges and the cost of a weigh at a truck scale if you want to be precise. This is what I did.

    While the explanation is a bit sparse, http://www.lcool.org/technical/80_series/brake.html generally follows the factory procedure using pressure gauges. The weight specs are appropriate, I believe, for earlier 80s. I know the rear weight spec is different for my '97 than in the info on the page linked above.
     
    Last edited: Jun 19, 2005
  7. taccruiser97

    taccruiser97

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    I posted this some time ago, but I bought a ready made bracket from Northwest Off-Road for my cruiser. It compensated for the OME lift. I put on and I have not experienced any brake wear issues. Didn't have to screw with readjusting the valve either. I forget what the part number was, but they only sell two brackets, one for 2-3" lift and one for a 4-6" lift. You might give them a try or make your own bracket.
     
  8. hill

    hill

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    I just purchased a similar bracket from Man-a-fre for about $10.00
     
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