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  1. #1

    Default Idler arm rotates too far- 1989 GMC pickup

    Hello,

    I've got an 89 GMC, 2wd, LWB, 5.7L with 75,000 miles on it. My Dad bought it new, and he didn't drive a lot, so it's low miles for its age, has had an easy life and been maintained, but its still a 23 year old vehicle.

    Here's the problem: I can turn the steering wheel so far to the left that it allows the idler arm to cross over to the wrong side. This leaves me with both front tires pointing inward. To correct, I have to jack the truck up and use a hammer to knock the idler arm back over to the correct side. Maybe another way of describing this is to say that if the idler arm should always travel in the top half of the semi circle, then it now has enough movement in it that it crosses over and travels in the bottom half of the semi circle. This happens when turning left, and is more prone to happening while backing up. I did see that my idler arm had a lot of slop in it, so I replaced. This did not correct the problem. I've looked under the truck with somebody rocking the steering wheel....I do see just a tiny bit of slop at the point where the pitman arm meets the center link, but it's not much. I can't see anything broke, bent, or missing. I'm really stumped. What limits the steering travel on this truck? I don't see a physical bumpstop. Is the steering radius limited inside the steering gear box? Is that out of adjustment?

    I appreciate any words of wisdom you can lay on me.
    Thanks.
    John

  2. #2
    Legend

    Join Date
    Sep 2010
    Location
    everett, massachusetts
    Posts
    1,312

    Default

    THE idler arm vertical movement should be 1/8inch max. I would check out the other components for excessive movement and wear. these vehicles had high failure rate on the front end steering components.

    use a lithium based grease . grease twice a year.

  3. #3

    Default

    j cat, thanks for answering. My old idler arm definitely had more than 1/8" travel. It was pretty sloppy. I recently put a new one on so it's now tight. My brother replaced the pitman arm for my Dad about 4 years ago. That arm has less than 10,000 miles on it. My excessive travel in the idler is in the arc that the arm rotates in. I don't know what the actual rotation numbers are, but as an example, if it was supposed to rotate through a 110 degrees of arc, its now rotating 200 degrees. It allows the idler arm to cross over it's center point, and to begin rotating on the wrong side. That causes the wheels to be pointed in opposite directions, and means the truck will not move at all. I've done a bit of looking underneath with somebody turning the steering wheel...I just can't find what is letting this happen. It allows the wheels to turn too far to the left. That's why I thought that maybe there is something that is supposed to limit how far the steering is allowed to turn,...maybe something in the steering box? I don't know. It may very well be caused by worn parts, and I'm just not sure what to look for. I've watched the linkage points at idler, pitman, and tie rods, looking for some excessive movement. I'm just striking out on finding the cause.

  4. #4
    Legend

    Join Date
    Sep 2010
    Location
    everett, massachusetts
    Posts
    1,312

    Default

    IT could be the steering box. with 75,ooomi maybe not. jack up one side at a time and pry on the lifted wheel check for worn sloppy components.

    jack up a wheel place a support [block of wood] under the lower A frame then using a pry bar check the ball joints upper/lower for movement.

    it is possible your 89 had rubber bumper stops that prevented this excessive steering travel.

  5. #5
    Sr. Apprentice
    Join Date
    May 2010
    Location
    Ft.Worth,TX
    Posts
    43

    Default

    Youre idler arm is upside down.
    2008,2500 silverado,k-n filter,flowmaster 7o series muff. linex bedliner.

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