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4x4 diaphragm actuator problem

Discussion in 'Mitsubishi Minicab' started by Caleb Roth, Oct 5, 2013.

  1. Caleb Roth

    Caleb Roth Member

    1994 minicab 4x4 4 speed hi/lo
    Ok here is the deal I have no 4x4 dash light and the 4x4 won't engage.
    With the key on I can hear the front diaphragm click and puff a little air but no lock into 4x4 when I push button.
    If I put the truck up on jack stands with it running in gear I can use a pry bar to manually engage 4wd.
    If I turn the truck off then it automatically goes back into 2wd. Also with the engine off I cannot pry it into 4wd.

    There is vacuum going into the diaphragm & it does click when I push 4x4 button.
    I assume that the diaphragm is leaking and the 4x4 dash light must just be shot.

    Anybody have any ideas?
  2. Roger

    Roger New Member

    I have a 200 model stuck in 4WD, did you ever find a solution?
  3. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    Don’t know on the Mitsi, but on my Hijet, there are two vacuum lines, and one is sued to disengage the actuator.
  4. Roger

    Roger New Member

    Will check it out
  5. wheelio

    wheelio New Member

    Hi Jigs,
    I have a question about the attached photo below.
    I am replacing my vac lines and I started taking the T's off before I realized one had a restricted port. I put it back where I think it goes but not sure.
    Do you know what line needs the restricted port and why? Only changing one line at a time from now on.

    airbox vac lines.jpg
  6. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    I think the restricted port would be on the engine side, and then feed out to the vacuum reservoir can for the shifters.
  7. wheelio

    wheelio New Member

    I Didn't mean to off topic post a trick question but it was for the air filter box vac lines. I should have started another thread rather than replied to the shifter discussion from last year.
    My problem is I cant figure out what these two ports on the air filter are for and how it works. Is there a choke flap in there modulating air? maybe i should swap the two T's in the image above, that would restrict/delay vacuum downstream to all this. I also added a similar truck parts diagram . I am trying to understand how this works. Do you know how the intake vacuum controls all this? maybe one of those ports should be restricted to cause a differential. As usual I will keep poking around until I figure it out or break it. Sure wish I weren't so quick to pull those damn T's before i checked to see if they might be valved.

    air cleaner.jpg
  8. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    They might be part of the system that brings air over the exhaust manifold to warm it when the engine is cold, and switches to ambient air, once the engine is warmed up.

    Easiest way, to check might be one of the hand held vacuums pumps.

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