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Can you adjust a steering gear box on an IFS like a SFA?

Discussion in 'The Garage' started by Pookster, Sep 20, 2004.

  1. Pookster

    Pookster 1/2 ton status

    Nov 21, 2000
    Likes Received:
    NYC, NY, USA
    I have a little bit of "play" between where my steering engages and where my wheels move-. I've checked the end links, and they are all ok, and not moving when I twist the steering wheel. All the play seems to be within the box.

    Is there an adjustment screw?
  2. dontoe

    dontoe 3/4 ton status GMOTM Winner

    May 7, 2004
    Likes Received:
    Hickory, N.C.
    I just recently read that the adjustment screw on the steering box only sets preload and doesn't help in anyway with loose searing though in the past I have tried adjusting it. Worn parts or loose bearings are supposedly the only real reasons for loose steering.
  3. ugly_blazer

    ugly_blazer 1/2 ton status

    Apr 12, 2004
    Likes Received:
    Have you checked the pitman arm and the idler arm? I had to replace both on my '95.
  4. Triaged

    Triaged 1/2 ton status

    Feb 21, 2001
    Likes Received:
    CA (LA/OC area)
    I have posted on this before if you want to search for it.

    The allen set screw on top of the box adjusts gear mesh. It hardly ever needs to be adjusted (but is often the first thing people do to try and tighten it up). The one that needs to be adjusted more often (and if you are going to adjust the gear mesh you have to adjust this first) is the input shaft bearing preload. There is a LARGE stamped steel lock nut under the rag joint. After you loosen that you can adjust the bearing preload with a spanner wrench.
  5. readymix

    readymix 3/4 ton status

    May 30, 2004
    Likes Received:
    Murrieta, California
    I have been asked about the IFS chevy steering system so many times i made a quick write up on it. Here you go......

    Steering system check for full-size IFS Chevy trucks (With or without EVO)

    Listed below are the components you will check in the order you will check.

    --Place the truck on jack stands.
    --Spin the wheel around and listen for any noise other than what is caused by the brakes.
    --With one hand on the top and the other on the bottom of the wheel, move the wheel in and out on the spindle. If there is any noticeable movement the wheel bearings will need servicing or replacement. Wheel bearings can only be serviced on 2WD trucks

    --Remove wheel
    --Place floor jack under the LCA and lift slightly.
    Upper Ball Joint
    --Using a screwdriver or pry bar, pry up on the UCA and look for slop on the ball joint.
    --Wiggle the knuckle around and again look for slop in the ball joint.
    Lower Ball Joint
    --Measure the distance between the tip of the ball joint stud and the back side of the ball joint (or grease
    fitting if installed).
    --Now lower the jack and re-measure the ball joint again. If the difference is more than 3/32” you must replace the lower ball joint.

    If either of the ball joints are bad I recommend changing them both while you have it apart.

    Now reinstall the wheels and lower the truck.

    For the remainder of the check you will need the assistance of a friend.


    --Remove the front differential skid plate and cross member skid plate if so equipped.
    --Have your friend move the steering wheel back and forth a few inches. Not enough to move the tires but enough to put force on all of the steering components. It may or may not be necessary to have the truck running for this. I usually leave the engine off with the key in the run position.
    --Look for any play in the above listed components.

    The sector shaft is what the Pitman Arm attaches to on the steering box. The sector shaft should start to rotate a little but should have ZERO side to side movement.
    The idler arm is on the opposite fame rail but in the same location as the steering box. The check for the idler arm mount is the same as for the sector shaft.
    There are 4 tie rods to check, 2 on each side. One attaches to the center link and the other to the steering knuckle. If there is any play they should be replaced. The tie rods should also be checked by pushing up and then pulling down on them while looking for play.

    All of the above listed parts are relatively simple to change if found bad with the exception of the sector shaft bushings. If they are found to be bad it is easier to replace the steering box. Usually when they are bad the truck will experience what is known as “DEATH WOBBLE”. It is much like bump steer except it is uncontrollable usually between 20-40 Mph.

    Three things can cause a crooked steering wheel.
    1. The tie rods ends were not properly adjusted for steering center when the truck was last aligned.
    2. The Keyway splines are twisted on the input shaft of the steering box (not repairable, steering box must be replaced or rebuilt)
    3. The splines on the sector shaft could be twisted. Keep in mind that the standard Chevy Saginaw type steering gear has a 16:1 reduction ratio. So if the splines were twisted by only 2 degrees the steering wheel would be off by 32 degrees. I don’t know about you but I have not been able to visually tell if the splines are twisted by that small of an amount.

    Contrary to popular belief Free play in the steering wheel can not be adjusted by the lash adjuster on hte top plate of the saginaw box. This adjustment only sets the pre-laod for the gear.
    1. On the top of the steering box you will see 4 hex head 10mm bolts holding on an access cover. In the center of the access cover there is an adjustment screw with a counter tightening nylock nut.
    2. Loosen the nylock nut while holding the center bolt (Lash Adjuster) still with an allen wrench.
    3. Turn lash adjuster clockwise to take up slack in the gear teeth and retighten lock nut. Do this by turning the lash adjuster about ¼ turn at a time then recheck the free play.

    Brian "ReadyMix"

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