The term “maintenance free” is about as absolute as “waterproof.” So don’t be lulled into thinking you can ignore axle and wheel-end components that are billed as low-maintenance. Yes, these products can reduce downtime due to blown seals, spent bearings, and sloppy lube jobs. But they still need regular attention, especially considering the potentially tragic outcome of a wheel run-off due to a seal or bearing failure.

Fortunately, low-maintenance hubs mean the steps to ensure your axles are in working order are relatively simple ones. Here’s a five-part plan to follow.

1STOP AND LOOK. Teach your drivers how to spot wheel-end problems during the pre-trip inspection. Usually, that involves nothing more looking for signs that oil may have escaped out the seal or through the hubcap area, and looking for oil on the brake shoe, says Todd Anderson, vice-president of engineering at Stemco. In an oil-bath system, drivers should check the lube level by looking at the fill line on the hubcap. Too, they should watch for a milky or cloudy appearance to the lube, which may indicate water contamination.

At any sign of trouble, get the vehicle off the ground, remove the hubcap, and check for end-play. Abnormal wobbling could indicate problems with bearing adjustment or rollers. Also look for lubricant on the frame-air flowing underneath a truck at highway speeds can blow the lube away from the axle, disguising leaks.

2 EASY PIECES. Whether you’re replacing seals, bearings, or working on brakes, reassemble the components correctly. That means getting the bearings seated, the right bearing adjustment, and using the proper amount of lubricant.

Your wheel-end or axle supplier can talk to you about installation procedures. They’ll differ depending on the manufacturer, but every one will say to make sure the seal is fully bottomed out, or seated, in the hub bore or on the spindle shoulder. If the seal is cocked, with one side higher than the other, it will wear unevenly.

Many wheel-end problems are the result of contamination during installation. Metal particles, rust, or dirt can cause the seal to fail. Clean rust on the hub bore or spindle-you don’t have to get the pits out of it, but you do need to get that rough slag off. It impedes the seal from doing its job.

3The seal’s not the end of the deal. Once the seal is in place, keep it there. “People will install a new seal into a hub, place the hub on the spindle, then pull it off again for some reason,” says Steve Slesinski, director of product planning for Dana. “They damage the seal without knowing they did so.” The outer end of the hub needs to be properly supported as it is placed back onto the axle or spindle.

The biggest bugaboo in reassembling a wheel-end is bearing adjustment. The American Trucking Associations Technology and Maintenance Council offers a Recommended Practice, RP-618, which recommends using a dial indicator to measure wheel-end adjustment. “It’s like boiling water,” says Tom Smego, director of sales at SKF/Chicago Rawhide. “You know it’s hot, but until you put a thermometer in it, how hot is it? Until you put a gauge on the wheel-end, you don’t know how much end play you have.” It should measure no more than five one-thousands of an inch of end play.

Too tight is worse than too loose, says Stemco’s Todd Anderson. Loose results in a much more gradual failure. “Typically, you’ll get a wheel seal failure before you get a gross bearing failure, so it gives you an opportunity to get it right,” he says. “If you have something too tight, it fails rapidly. You will not get an early warning.” He notes that some people are installing wheel-ends using preload as part of the bearing adjustment. However, once you install preload, there’s no way of measuring how much you have, so if you over-tighten, you won’t be able to tell, and you can cause damage to the wheel-end.

Not everyone signs on to the dial indicator procedure. Federal Mogul, for instance, has a patented device that it claims is a more accurate way of measuring end play. The key, says John Butler, a field service representative with Federal Mogul, is to have a good procedure and stick to it.

4 The right amount of lubrication is vital. If you’re using grease, pack the bearings. With oil, pre-lube them. After assembly, fill the hub cavity with grease or oil. Forgetting this step can cause catastrophic failure, Butler says, especially on drive axles. “It takes about 30 minutes for the rear end to provide enough lube, and in the meantime, you can weld the bearing to the spindle.”

How do you know you’re using the right amount of lube? Here’s a trick: If you’re using oil bath lubrication, it takes a little time for the oil to work its way through the bearings as the wheel-end is filled. Step away for a while, then come back and check the level again. To get the right amount of semi-fluid grease, many fleets measure or calculate how much is needed for that application, then meter out that volume or weight in the shop to take away much of the guesswork. If you’re using hard-pack grease, pack the bearings and make sure there’s enough grease around the bearing rollers, and fill the sump of the hub cavity in the wheel-end.

A good time to check the fluid levels is whenever the engine oil is changed. Don’t make the mistake of checking the level by dipping a finger through the fill hole and think that if you feel oil, the axle is full. Oil should be at the same level as the fill hole in order to fully lubricate all necessary components. If the oil level is extremely low, look for leaks.
Synthetic lubes mean you don’t have the change the axle oil for 250,000 miles or more. At that point, analyze it, especially for water contamination-spray from high-pressure washers can get through some of the vent systems on the wheel and let water into the wheel-end.

In general, use the lube specified by the OEM and axle manufacturer, use the proper amount of lubrication, follow the lubrication-change interval or schedule for the axle, and-if the axle is equipped with oil pump and filter-replace the filter whenever the lube in the axle is drained and replaced.

5 Spec low-maintenance hubs. Newer components are designed to reduce or eliminate the potential for mistakes. Front non-drive steer axles, especially, are increasingly being spec’d with some level of low-maintenance components.

Some axles have permanently sealed and lubricated hubs. ConMet’s PreSet hub assemblies feature pre-adjusted bearings with a spacer to positively set the bearing clearance, eliminating the need for manual wheel-end adjustments. Similarly, Dana’s LMS, or Low Maintenance System, combines a precision machined hub, premium wheel seal, premium bearings and precision spacer in a self-contained unit that can be torqued up to a predefined level; no bearing adjustment needed.

Going a step further, unitized hub, bearing, and seal assemblies make wheel bearing, seal maintenance, and wheel-end adjustment unnecessary. However, individual components can’t be serviced. If a seal goes in a unitized hub, the whole hub unit must be replaced.
Depending on what type of system you choose, you could be looking at tens of dollars to hundreds of dollars more in price. Whether that investment will pay off in reduced maintenance costs is something you will have to analyze for your fleet. After all, to say a component is maintenance-free just won’t hold water. SIn 1996, air-ride accounted for 36 per cent of suspensions spec’d for trailers. Today, that figure is nearly 70 per cent. One reason: new product designs are taking the air out of arguments that trailer air-ride is heavy or complicated to maintain.

Among the latest examples is ArvinMeritor’s RideStar RHP tandem-axle van suspension, which is being gradually upgraded throughout the year. “We’ve optimized the slider with integrated lateral plates and protected the pin mechanism with additional cross members,” says Jim Sharkey, who oversees the trailer systems business for ArvinMeritor in North America. “We’ve also moved the pin handle to the front of the suspension for easy access.” The lightweight, parallelogram design causes no roll torque on the axles, which means lighter axles can be integrated into the suspension system. Meritor’s new 5000 series axle is available; Meritor Q Plus brakes are standard. At the end of this year, the suspension will be renamed the RideStar RXP. Contact 1-800/535-5560 or www.arvinmeritor.com.

The Holland Group’s new CB400 builds on the company’s success with durable, high-alloy slider sub-frames. It’s an on-highway suspension with two axles at a 49-inch spread. Ride heights range from 15.5 to 18 inches and the beam centres are 36 or 42 inches. As a suspension, the CB400 is remarkable on its own, but two features distinguish it: Qwik Release, a pin-pull system that simplifies the back-wrenching job of moving the slider around, and Swing Align, an innovative way to quickly and conveniently align the axles with the turn of a bolt. For details, visit www.thehollandgroupinc.com-a recently revamped site-or call Holland Canada at 519/537-2366.

Dana’s new Dana Spicer RF Series suspension is aimed at flatbed and tanker trailer customers. It has a number of hanger options, including weld-on and bolt-on versions with multiple top plate configurations. And it incorporates a lot of what you’ll find on the Spicer AdVANtage suspension-trailing arm design, large axle surface area, Spicer brakes, and low-maintenance hubs. The RF Series encompasses four ratings: 20,000, 23,000, 25,000, and 30,000 pounds. Go to www.roadranger.com or call
1-800/826-4357.

Ridewell has built a reputation as a maker of mechanical and air suspensions for demanding truck and trailer applications. Its Ridelite product is no different. The 25,000-pound-capacity, integrated suspension for platform, tank, dump, grain, and other specialized trailers has pre-mounted shock brackets and attachable, no-weld valve mounts to make installation easy. A variety of five-inch round axles make it possible to replace or maintain axles while preserving other parts. Call 905/577-5838 or see www.ridewellcorp.com.

At 20,000 pounds capacity per axle, the ReycoGranning 20AR/RS3162 DockMaster II from Tuthill Transport Technologies was built to be the lightest air ride slider on the market. It shaves weight by using narrow beams and hangers, only one main crossmember, and has no u-bolts in the axle attachment. ReycoGranning suspensions were the first designed to reduce dock-walk. Contact: 1-800/753-0050 or transport.tuthill.com.

For tridem-happy Canadians, Hendrickson has added a top-mount tridem configuration to its VANTRAAX slider line (which uses the INTRAAX air suspension system). The overall capacity is 52,000 pounds–it comes with axle ratings of 23,000 pounds or a heavier-duty 25,000 pounds in ride heights ranging from 14 to 19 inches. Contact Hendrickson International’s trailer suspension group at 1-866/RIDEAIR or www.hendrickson-intl.com.