Alignment issues

Discussion in 'Trucks [ Eighteen Wheelers ]' started by HillbillyDeluxeTruck, Jun 15, 2024.

  1. HillbillyDeluxeTruck

    HillbillyDeluxeTruck Road Train Member

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    I have been fighting an alignment issue on my 379 for the last couple of weeks after replacing my front leafs/bushings. Now to preface this, my kingpins are worn and will be getting done soon.

    But here's the issue. After replacing the springs a few weeks ago, the truck started pulling right. It lead to me buring down the outside part of the right tire. This made me think that it was an issue on the right side.

    After measuring and measuring, racking my brain and even trying and failing to get an alignment shop to do the adjustments I wanted, I realized that it wasn't the right side, but the left. I also remembered that roughly 3mo ago, I found left side ubolts loose (I tightened them). Now I believe that when I did that, I didn't have the axle back squre, then when the springs were replaced, the axle was set back square and thus my current alignment issue (they did not align the truck because of the worn kingpins).

    When looking at the gearbox, steering arm, drag link and knuckle on the driver side, the steering arm does not sit at 90 deg perpendicular to the ground, it is aimed slightly forward towards the front of the truck which is also pulling the knuckle forward. When the truck is going forward, I think the gearbox is trying to center itself which means its pushing everyghing else to go right.

    Does all that make sense? Lol. Im trying to figure out how to reset everything back to center myself since Im unable to get a shop to listen to me. I can't have the truck down for roughly another week to 10 days before I do the kingpins. I have the tools, I just dont know the procedure.
     
    Last edited: Jun 15, 2024
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  3. wore out

    wore out Numbered Classic

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    CHASIN THE DEVIL'S HERD
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    You need a tape, a string a plum Bob and a piece of chalk.
    Center of steer to center of steer ( drop your plumb Bob off center of tire mark floor) you want it no more than 1/8” toe in or the front of tires need be a 16th no more than an 1/8 closer than the back this is also with wheels pointed straight don’t worry bout steering wheel position yet.
    Then pull your outside drives measure from the center of steer spindle to center of rear drive axle on both sides get that measurement as even as possible by shimming one side or the other. Then center of rear drive to center of front drive axle. Shim the front so both sides are as close to same measurement as you can get, that’s gonna help your thrust angle. Now if you have slack in spring pin bushings or the rears your pissing in the wind because if it’s floating back and forth you ain’t getting anything square
     
  4. MACK E-6

    MACK E-6 Moderator Staff Member

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    Are you describing a finished job here or something to at least get you in the ballpark so a shop can make final adjustments?
     
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  5. wore out

    wore out Numbered Classic

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    I always double check it eventually. I have had good luck with that all my life. I check castor with a plum and angle finder and camber I pretty well know where it needs be. Guy that does most my alignments says Im an easy customer. I had to have a steer axle bent one time cause the camber I couldn’t hit. But other than something odd like that it’s pretty close.

    the spindle and the axles usually have a dot In center. So I pull the wheels so I know my eye ain’t crooked. We used to pull strings on out frame work then x them line them with a tape and out the door. I won’t say it’s right or wrong. I certainly won’t say it’s as accurate as a laser machine with a well oiled alignment man running it. Just something I learned in a 1 bay shop on the side of US 67
     
  6. wore out

    wore out Numbered Classic

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    There’s gonna be tie bolts that hold the spring and axle in place unless the head shears which can happen when loose. There are tapered shims with cut outs to allow them to be slid in between the top of axle and spacer block. They go opposite of each other. Their purpose is to put that beam in a twist if you put thick edge same way on both it will really lay it down or stand it up. Low leaf trucks the thin side of shim goes forward on right spring thick side forward on left. The air leaf trucks use really thick tapered spacers no shim. Right side short side forward.

    after re reading the OP his problem is gonna be toe setting. The cross bar is possibly bent. Either way I’d start with toe.
     
  7. Brandt

    Brandt Road Train Member

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    MD alignment has video you can watch including DIY with tape measure and string. They say it better then laser because you align the truck by what the tires are showing you not what computer says or what in spec range by factory.

    they have different shops around the country using their system. the guy in Kansas City famous for doing the right job plus you can watch and he will explain everything.

    if can do it your also in you watch the video
    IMG_8796.png
     
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  8. BoxCarKidd

    BoxCarKidd Road Train Member

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    It has been a long time for me. I have a truck and a car alignment rack that had to be moved for eminent domain. Augusta Golf Hall of Fame. That put several companies out of business. Then the Hall of Fame became unattended and grew up in weeds. Our government at its best.
    Before being set up the racks had to move again. This old man is never going to put them together again. If anyone is interested you can get them for a little more than scrap price.
    I am not putting out a sales pitch just meant to share. While I struggle to follow wore out, because of the way he stated it, toe in has the most dramatic effect on steering tire wear and is the easiest to adjust.
    Caster is the angle of the king pin. Like the front wheel on a shopping cart is offset. When you put new springs on that will change the caster. Shims are used between the axle and the spring to adjust the caster. Many people thank caster cannot create pull but it can. Especially if it has combined with camber and toe in that are all in specification but to the outer limit of what is allowed. School kid with the best equipment has all the readings within specifications. He cannot understand that toe in, caster, camber and rear axle alignment all pushing to the same direction will cause pull. Machine says it is is specs. That is all he knows.
     
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  9. BoxCarKidd

    BoxCarKidd Road Train Member

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    I prefer to to stay out of the subject but only trying to help. Last time I got into a subject like this someone else suggested they go to a professional alignment shop. I respect him and you probably should after you do the king pins.
    How about this: When I worked for a major company and people were complaining a upper management guy came in. We rolled a truck forward a bit. Then he drove a thumb tack in at spindle height behind the steer tires and cut the heads off. We measured across them. Started with the 10 inch mark. That removes doubt about the piece on the end being able to to move. Rolled the truck forward one half tire rotation. Used tire bars under the drive tires and did not let it role back.
     
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  10. HillbillyDeluxeTruck

    HillbillyDeluxeTruck Road Train Member

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    I thought it was a toe issue too, but I found a shop in Fairfield, Tx that put a tape on it and got the toe set at 1/8" from front to back.

    Im gonna take pics tomorrow and post them.
     
  11. wore out

    wore out Numbered Classic

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    I would be interested in an old school alignment rack.

    I am not the best at explaining things sometimes. I used to call the cross bar the drag link. Then some fancy pants McGee told me that the drag link was technically from the pitman arm to spindle. And the tube between the tie rods is a cross bar. Now I ain’t sure either way. But he sure lined me out way he put it to me.



    We would find center of the tire then turn the tire all way around leaving what we were using as a scribe stationary. I always heard of those toe sticks I think they are called but never used one
     
    Last edited: Jun 16, 2024
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