Experts offer tips on wheel-end maintenance;Axle alignment should not be overlooked
September 1, 2008
TORONTO, Ont. - Waiting til something goes wrong to check for issues with your trailer wheel-ends is about as smart as waiting til you're sick to visit the doctor, according to the experts at the Cana...
TORONTO, Ont. –Waiting til something goes wrong to check for issues with your trailer wheel-ends is about as smart as waiting til you’re sick to visit the doctor, according to the experts at the Canadian Fleet Maintenance Seminars session on trailer wheel-ends.
“The options are narrowed down quite a bit at that point and it’s the same with maintenance,” pointed out Ron Gervais of the Freinmeister Group, part of the panel which also included Rob Monster from the Ontario Ministry of Transportation and Bill Ratliff from Timken.
In Ontario, according to Regulation 611 of the Highway Traffic Act, trailer wheel-ends must be inspected annually “but just because the regulation says once a year, doesn’t mean that’s good enough for you operation,” cautioned Monster. “You have to base it on your rate of wear.”
For example, a bus fleet may need to be checked every two months. Vocational fleets may also need inspections that are more frequent than annual.
A proper inspection should include the following steps, according to Ratliff:
1. Get the wheel off the ground, spin it to check how smoothly it runs, and “listen to your wheel bearings.” If there is any deterioration in the system, you will hear it. Too noisy in the shop to hear well? Ratliff suggested putting a two-foot piece of 1.5-inch hose to your ear with the other end applied against the hub cap to hear better. Or you can use a stethoscope.
2. Feel for excessive end play. Since that’s a judgement call that can vary from mechanic to mechanic, use a dial indicator if you have any concerns. If the end play exceeds the maximum allowable for adjustable wheel-ends, do not simply adjust the wheel bearing. You must remove and inspect the system as under normal operating conditions end play should not increase.
3. Inspect the seals. If you are running oil or semi-fluid grease, you must inspect for any signs of leakage. If it’s running on to the face of the hub, it’s best to change the seal, Ratliff advised. Grease seals should be dry and dirty on inspection. If they are found to be leaking, it’s likely too much grease was placed inside.
4. Check the condition of the oil. There are several things to consider: Is there enough oil inside; is there milky water contamination; does it smell when it gets hot; and is there any metal debris when you insert a magnet? If any one of those indicators are found, then you need to conduct a closer inspection.
During his many years in the maintenance business Gervais has seen his share of dangerous practices involving trailer wheel-end inspections, such as resorting to the cutters to solve the problem of trailer warning lights that stay on and S-cam bushings that “if I could shake them, would ring like a bell.” And it’s not just the fleets that make errors. He showed pictures of pushrods taken straight from a manufacturer’s brochure that had an incorrect length. Although there is a long list of things to consider, some of his most pressing points included the importance of using a dial indicator. The dial in procedure calls for each automatic brake adjuster to be checked with the factory-supplied template to ensure the release angle of the adjuster meets the manufacturer’s requirement.
“It is not an exact science but a simple check can help get this right.
Sometimes the correction is a few turns of the clevis yoke,” he said.
Ratliff added that in his experience only about half the shops he visits have a dial indicator and of those only about half actually use it.
“That’s pretty sad. Maybe it’s because the system they have takes too long to set,”he said, adding there are systems that can be set up in under a minute. Gervais also stressed the need to understand the importance of axle alignment to vehicle performance.
“Axle alignment is critical. If it is biased, your fuel mileage goes to hell, not to mention what will be happening to your tires. If it’s making a noise, take it off and check. Failing to do so is just asking for trouble,” he warned. •