Question about 1999 Dodge Ram

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Front hubs won't engage

For years I have been reversing the vacume lines on the actuator to engage the hubs for the 4 wheel drive. That no longer does the trick. Got any advice? I have repaired any broken vacume lines I could find (2)Jim

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  • jms1911 Jan 13, 2009

    The acuator is bolted onto the frame in front and the back has nothing on it. However the left side of the actuator seems to be the electrical contact side and the right side has what seems to be a diafram housing with 2 vacume tube openings on it. It is these 2 tubes that I have been reversing to engage the hubs. It is this back yard repair that does not seem to work. I will check out every inch of the rest of the tubing as you suggested. Thanks. Jim



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I just changed the vacuum lines on my daughters truck. One of the steel lines was corroded and plugged. I put in two new lines and all is well.

Posted on May 02, 2009

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If you have a vacuum pump (bicycle pump wil work) , hook up to the very rear of the acuator, give it some vacuum and listen for it operating. If it doesnt then the actuator may be bad.
If it does make nooise and move, a check for leaks in your vacuum system is in order. Just follow the pipes around and inspect them (engine running) and listen for leaks.
Hope this helps...

Posted on Jan 13, 2009

  • Tim Higgins
    Tim Higgins Jan 14, 2009

    check out those electrical contacts there a fuse for the actuator? Is there power to the actuator?

  • Tim Higgins
    Tim Higgins Jan 14, 2009

    check out those electrical contacts there a fuse for the actuator? Is there power to the actuator?



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