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Technical Need rear axle alignment help

Discussion in 'The Hokey Ass Message Board' started by txcr13, Jul 9, 2018.

  1. txcr13
    Joined: Feb 15, 2010
    Posts: 242

    txcr13
    Member

    Sorry for the long post, but wanted to include enough detail first time around.
    Installed an extra leaf in both springs on rear axle. The rear end sits on top side the leaf springs. During spring disassembly, I noticed that the tie bolts in the springs had been installed upside down, with excess threads pointing up and not cut off, and they extended up about 1-1/4" toward the axle tubes/spring mount plate. Both bolts contacted the housing, and bent to about 20 degrees when the u-bolts were pulled down hard on the lower spring plates. I installed new tie bolts, trimmed them level with the nut, properly located the bolt heads in the mounting holes in the upper spring plates, and tightened up the lower spring plates.

    Fast forward. Now the lower back edge of the passenger side wheel well rubs the tire, just about at axle centerline. This didn't happen before the new leafs were added.

    Looks to me that the rear springs aren't mounted square. The frame has been smoothed and painted, and unfortunately the old rivets/holes/reference points in the frame all disappeared. The front mounts on the rear spring would REALLY be a mess to move due to its configuration. Plus I don't want to be out the time and $$$ at this point in the project.

    Soooooo, checking rear end alignment as best I can at home, using a measuring tape from the front axle mounting tabs (which I believe to be correctly positioned) to front edge of upper spring plates welded to rear axle, the passenger side of the rear end is 1-1/4" further back than the driver side.
    Measuring the clearance from front edge of passenger side rear tire to wheel well tells me that moving the rear end forward 1" to 1-1/4" will position it just right.

    Question: The driver side does not need to be moved. The fix I have in mind is to use a universal leaf spring relocation plate, which has holes in it to allow moving the rear end either 1/2" or 1" from stock location. Also, the holes in the upper spring plates have about a 1/4" of adjustment in them for the tie bolts. The springs are approximately 56" long, so I don't think this would be harmful to the springs, or make the car ride funny with one side mounted slightly off center. Not the ideal fix, but I think should work fine?? I wanted to check and see if you gents have any different thoughts. Plus, any tips for another method to check if the rear end is square with the frame would be appreciated.
     
  2. Any chance you turned one of the springs around?
    Many of them are not symetrical eye to pin
    1-1/4" is a bunch
     
    catdad49, Casey Riley and Moriarity like this.
  3. txcr13
    Joined: Feb 15, 2010
    Posts: 242

    txcr13
    Member

    Yes, it is a bunch. I am sure I have the springs in right, but I will triple check. In any case, that is a very good suggestion, thanks.
     
    Casey Riley likes this.
  4. flamedabone
    Joined: Aug 3, 2001
    Posts: 5,706

    flamedabone
    ALLIANCE MEMBER

    If it was fine before you messed with it, start there first. If it was always 1 1/4 off, then you can start looking at the mount.

    What kind of car is this?

    -Abone.
     
  5. AngleDrive
    Joined: Mar 9, 2006
    Posts: 1,163

    AngleDrive
    ALLIANCE MEMBER
    from Florida

    Measure your X from left front to left rear. I usually do this with a plumb bob and masking tape on floor with the axles on jack stands so everything is loaded. Then measure wheel base. You need to make sure the axles are inline with each other and centered on the center line of the chassis.
     
  6. txcr13
    Joined: Feb 15, 2010
    Posts: 242

    txcr13
    Member

    Yes, it was fine before I messed with it, with bent tie bolts pushing the rear end out of position with the spring plates. I am afraid the mount got welded in place with the rear end out of position on the springs, but with the wheel centered in the wheel well.
    The car is a 1946 Studebaker coupe.
     
  7. txcr13
    Joined: Feb 15, 2010
    Posts: 242

    txcr13
    Member

    I am a frame measurement rookie, so I need to ask, what is an X measurement?
    What points are the measurement taken from and what is the best way to take the wheelbase measurement?
    Thanks.
     
  8. oldolds
    Joined: Oct 18, 2010
    Posts: 3,593

    oldolds
    Member

    Some aftermarket spring saddles have 2 locating holes in them. This is to change the location of the rear on Chevys when you eliminate the torque tube. It is about 1.5 inches.
     
  9. txcr13
    Joined: Feb 15, 2010
    Posts: 242

    txcr13
    Member

    Mystery solved. The problem was me.
    I thought my way back through all the disassembly and reassembly of the springs, and the measurements I took.
    At one time when I lowered the car down on the springs, I later noticed that the rear shackle on passenger side had rotated toward the rear axle, instead of toward the rear of the car as they should. I think maybe this caused the wheel to be off-center.

    Today I triple checked everything. Loosened the spring plates, verified the heads of tie bolts were seated in the upper spring plates, etc. Now that it is all back together, the driver side of the axle is now about 1/4" back of the driver side. I will drive it and see how it does. Not sure how much tolerance in rear axle alignment is allowable??

    Thanks to everyone who responded. I appreciate it.
     
    Casey Riley likes this.
  10. Wish they were all that easy
     
    txcr13 likes this.

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