When the DUST CAP Is MIA

Any boat trailer owners know the feeling: After a dutiful inspection of the trailer and boat while en route to or from the boat ramp, a look at their dust cap or bearing protector on the hub shows it's gone. In too many moments like this, it's sitting on the side of the road miles away from where the trailer is currently located.

First, some basics: Located inside the hub, the trailer bearings are packed with grease, seals, races and assorted other parts designed to make the wheels turn smoothly at a cool temperature. To keep dust-dirt-salt water-fresh water and anything else found along a highway, driveway or boat ramp out-and to keep bearing grease in-dust caps (also called bearing protectors) are placed over the hubs. But sometimes, the cap comes off and when it does, problems occur.

"These dust caps or bearing protectors are usually the ones folks just took off to do the lube job (on the bearings) and so it makes sense that now the same ones that used to stay on don't anymore," observes Trailering Club Member Kris Frame from Kent, Washington. "I had the same problem for a couple of weeks after I did the first brake/lube job on a used boat trailer I bought. I was new to all of this and I went through enough replacement protectors that I was getting concerned about the cost, not to mention the fact that I had to repack the wheel every time because I had compromised the cleanliness of the installation every time the cap fell off. Plus, I would get to the ramp, realize I had lost the cap and then would'nt be able to launch the boat out of fear I'd expose the bearings. It was exceedingly frustrating."

Dan Jenkins, vice president of Bearing Buddies, one of the major bearing protector manufacturers, says if new dust caps or protectors fall off, then it's probably time to look at the hub as the problem. However, if you are having this problem with protectors that aren't new, turn it over and take a look inside.

William Glidewell, chief executive officer of Kodiak Trailer Components (manufacturers of Red Eye bearing protectors, among others sold at West Marine), says Kris Frame's experience isn't unusual. "My opinion is that after the bearing protector has been installed in the hub for an extended time (several months), its outside diameter takes a 'set' and if removed, will not spring back to its original diameter. Accordingly, if the bearing protector is then reinstalled, the interference fit will be less and it will be more prone to come out." Keep in mind, however, that not every dust cap or bearing protector uses the "press fit" (it is secured on the hub with a mallet). Tie Down Engineering's oil bath TurboLube cap screws into a specially machined hub.

Tie Down's Vice President of Marketing Merrill Sutton (manufacturer of SuperLube and SureLube bearing protectors) echoes that idea. "The removal is just as important, if not more so," he says. "The cap should be removed with a rubber mallet, gently tapping the cap out, moving around the outer edge. Most people just hit them with a hammer, making reusing them impossible. Once the cap is out of round, it is
difficult to keep it in the hub."

George Knutsson, who along with Mike Pellerin provides expert answers in the BoatU.S. Trailering magazine Q & A section (and who used to own a boat trailer rental company in Florida), says there's a right way and a wrong way to secure a
dust cap.

"You need a rubber mallet and you need a piece of 4x4 (though others say a 2x4 works just as well)," Knutsson instructs. "The key to keeping a dust cap/Bearing Buddy/protector on is to hit it evenly so that the force of the hammer is applied evenly across the entire surface of the dust cap. Otherwise, it's going to go on unevenly and that's why the cap is going to come off."

This is not the time, by the way, to improvise. "What we don't want is to have the consumer try to install the bearing protector with a metal hammer," says Kodiak Trailer Components CEO Bill Glidestone, "because that can easily disfigure it. A rubber mallet might be another alternative, but many consumers may not own a rubber mallet."

One other reason why dust caps and bearing protectors disappear off a hub is the injection of too much grease into the bearing during servicing. It should be noted this only applies if the protector doesn't have a built-in relief mechanism that allows excess grease to escape out the front of the protector (most protectors have this feature so do an inspection if you're not sure). This can destroy a seal in the bearing and that's when you'll see grease splattered against the underside of the trailer, if not the fender. When doing service on your own and applying grease to a protector, be sure to use a hand-pump grease gun.

Overfilling was the reason Bearing Buddy designers decided to produce a bra in the 1970's. "It came about in an unusual way," notes Bearing Buddy Vice President Dan Jenkins. "There was a bottling company called Sparkletts Water that supplied five-gallon plastic water containers sealed with a vinyl cap to homes. Some inventive boaters who were having a problem with excess grease being slung onto their wheels figured out this vinyl cap would fit and stay on the Bearing Buddy quite nicely and prevent the grease-slinging problem. We heard about it and decided to offer the Bearing Buddy Bra as an accessory."

Jenkins says the secret to keeping a Bearing Buddy on the hub is to ensure the hub is the correct size in the first place. Because of trailer ownership changes and using different people to make trailer repairs, the hub and the dust cap or bearing protector can all too easily become incompatible. "To determine if the hub is the correct size," he adds, "use a pair of calipers and measure the I.D. bore (internal diameter) of the hub. When a Bearing Buddy doesn't stay on the hub, it's because the hub is oversized on the I.D. bore. The model number will tell you what the shoulder diameter-the portion of the protector that interfaces with the I.D.) should be. For example, Model 1980 has a shoulder diameter of 1.980. If the hub I.D. bore is greater than this, or is out of round, then the hub is the problem."

Another technique that works especially well when using the same cap is to flatten out the lip of the hub over which the dust cap/bearing protector fits-usually at 90¡ increments around the circumference. Before setting the dust cap over the hub, apply a coat of grease for an easier fit. But do this with the caveat that changing the design of the hub can also change its performance when underway, resulting in another lost dust cap/protector.

While a lost dust cap or bearing protector always causes a bad feeling, losing it and not knowing it's gone can be an even worse feeling. The good news in all of this is the fact that Trailering Club Members have Trailer Assist, which enables them to call BoatU.S. Dispatch from their breakdown location on the road and receive assistance from a service provider (bearing problems are the second most common problem handled on the road by Trailer Assist personnel). If the trailer can't be repaired on site, it will be towed to a nearby repair facility.

Tie Down Engineering www.tiedown.com

Kodiak Trailer Components www.kodiaktrailercomponents.com

Bearing Buddy www.bearingbuddy.com

What's in a Name?
Knowing what to call the protector is another issue. Dan Jenkins, Bearing Buddy Inc. Vice President, sees this on an all-too-frequent basis. "People commonly refer to just about every other bearing protector as a Bearing Buddy. The brand name has become so well known that it's like people saying Kleenex when they want a facial tissue. Yes, it is a problem, especially when they are having a problem with their bearing protector and assume it's a Bearing Buddy. Many times a year, we will get a pair of some other type of bearing protector returned to us by a consumer who thought they had genuine Bearing Buddys."