No Bum Steer Here

| January 05, 2005

Make sure that when you turn the wheel, your tractor goes where you tell it to.

When it comes to steering, you need to be 100 percent free of doubt when you drive. If you turn your wheel, the tractor must respond as you expect it to, whether you’re inching into a tight dock or dodging a wreck about to happen in front of you.

But like a lot of other equipment, steering is too often left untested and unchecked.
It’s not hard to do, and one day it might save you, or your load. Let’s start with the steering wheel itself.

If your steering wheel has play in it, the first thing to do is determine how much freeplay is allowable. You may be able to find the permissible freeplay listed in the owner’s manual. It will be listed in factory repair manuals, if you have them.

You can also look up allowable freeplay in the Commercial Vehicle Safety Alliance inspection criteria (see sidebar).

Finding out just how much freeplay you have is important because it’s a safety concern. If you have too much, it’s vital to find out why.

Mark Stathopoulos, the service manager at Bergey’s Truck Center, a Volvo, Mack, GMC and Isuzu outlet in Conshohocken, Pa., showed us the nine steps to finding, and fixing, steering trouble.

  1. Measure the freeplay
    Shut the engine off and open the hood. Turn the wheel back and forth until you feel pressure or resistance on either side, and try to estimate the freeplay. If it seems to be near the allowable limit, you will need to measure it more precisely.

    First mark the rim of the wheel. Then run a cloth or flexible metal tape measure around the wheel and hold it in place while someone else turns the wheel back and forth. You should be measuring the circular motion with the tape following the curve of the rim.

    If there is a significant mechanical problem, the freeplay will be well above the allowable limit, and you should proceed with the steps below.

  2. Watch it as it works
    A quick way to find trouble is to operate the steering while watching the steering mechanism as it works. To do this, first make sure the truck is in neutral and the parking brake applied. Block the drive wheels so it won’t roll. Then start the engine.

    Safely lean out of the cab and turn the wheel while watching the front suspension. If necessary, get a helper to operate the steering wheel so you can watch. Turn the wheel slowly from lock to lock, watching everything that is going on. Especially when you change the direction you’re rotating the wheel in, you may see parts moving in relation to one another that should be tied tightly together. For example, both ends of a U-joint should move right together. Or, you may see something flexing that should not be moving at all – like the steering box moving around on the frame.

    If you see one of these problems, you need to replace the U-joint or bearing that is allowing relative motion, or tighten or replace a component’s mounting bolts that are allowing it to shift around.

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