Revisiting bumpsteer and how to fix it

Discussion in 'Pedders Suspension' started by dms, Jul 22, 2010.

  1. dms

    dms LX Suspension Specialist

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    What is bump steer?



    Bump steer is the toe-in or toe-out of the front wheels as the
    suspension goes from normal ride height through full bump (suspension
    system moves up) to full droop (suspension system moves down).
    Measurement is usually limited to 3" up and 3" down from ride height. It
    is specified either by a graph or measurements.


    [​IMG]


    Why does bump steer cause tire wear?


    The toe in and toe out motion created as the suspension articulates over
    the road surface literally scrubs the tread off your tires. You can
    create the same grinding motion with your feet. With your feet flat on
    the ground, grind them until your toes point out and point in. The
    resistance is what causes tire wear as bump steer occurs.


    [​IMG]


    How is bump steer corrected on a Chrysler LX chassis?



    To revisit the Pedders solution, we replace the steering gear bushings, with a poly bushing (EP2113) that uses a center ferrule that is shaped like a stop sign. We then install the bushing and the ferrule so the mounting holes, which are off centered in the ferrule, are at 6 oclock. This effectively raises the steering gear, thus seriously reduces bump steer, or changes in toe as the suspension travels. We also have reports from lots of forum members that it also better isolates chassis vibrations that are transmitted thru the steering to the steering wheel. Installation of the kit take approximately one hour and should be performed with your next wheel alignment or when you purchase tires. The graph demonstrates the
    improvement.

    [​IMG]


    Here is the process
    1. With the LX in the air, and tires off the ground, disconnect the 2 bolts (3 bolts for AWD) that attach the gear to the front sub frame, and lower the gear. (DO NOT DISCONNECT ANYTHING ELSE). In the picture below, you can see the OE steering gear bushing

    [​IMG]


    2. Using a universal ball joint press, push the bushing out. In the picture it shows the reciever plate in the back being used. This is now not necessary. The push shaft will push the bushing into there rear opening of the tool. The only precaution is to avoid making contact with the tool threaded push rod to the eyelet of the gear. If it does, just take some sand paper and smooth out the contact so there is no sharp edges. A universal ball joint press is very common, and can be rented for $10-$15 or so. There is a thread on this forum where a creative member purchased some plastic pipe, washers and a long bolt and made his own press. The bushings come out very easy.

    [​IMG]

    3. Here is a picture showing the OE bushings and the Pedders EP2113 Bump Stop Bushings side to side

    [​IMG]

    4. The Pedders bushings come in 2 halves, and hand press into the gear itself after the eyelet has been cleaned, and any burrs removed. They are tight, but will go in by hand or with the help of a plastic mallet. Notice direction the bushings are installed, with the points at 12 and 6 oclock positions. This is important!
    [
    img]http://forums.peddersusa.com/imagehosting/74c48875580d8a.jpg[/img]

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    5. With the package comes a tube of special Pedders grease. Lubricate 100% of the hole service with this lubricant, then install the center ferrule so the hole hole is at 6 clock as pictured. Then wipe off the excess grease

    [​IMG]

    6. Once all Pedders EP2113 (EP2113a for AWD) bushings are installed, push up the gear so the bushing faces go into the mounting areas, and reinstall the OE bolts.. I like using a little loctite on all suspension bolts after cleaning the threads and torque to specifications

    [​IMG]

    More information on the Pedders bump steer can be viewed at our Pedders LX information page linked below including before/after graphs of bump steer


    As you can see it is a pretty easy bushing to upgrade and I think it is the easiest bushing in the LX platform to upgrade. Also you need to get your toe reset. It will change with the bushings installed because the gear is in a different location. Toe is a big wear angle for the LX platforms. You should have the toe set into the tight end of specs and not allow the toes to be just set into specs.

    Hope this helps, Any questions, just ask

    thanks
    mike