Filed under: Preparation & Readiness, RV Maintenance, RV Repair, Safety on the Road, Uncategorized
AN ELEPHANT ON ROLLER SKATES – Taking care of E-Z Lube Wheel Bearings on Your Towable.
April 7, 2012 by Professor95 · 6 Comments
Can you imagine an Elephant on Roller Skates?
Besides being able to actually stand-up and skate, the sheer weight of an elephant on the small axles, bearings, and wheels of roller skates brings images of frequently broken parts to my mind (Elephant on Roller Skates sketch by James Suhr) .
Realistically, a large towable riding on a conventional spindle and bearing system isn’t much different than putting an elephant on roller skates. That is a lot of weight for such small parts to handle.
Specially designed parts to handle the weight and suspension abuse our fast deteriorating highways inflict on our RV towables is a must. But, without proper maintenance, those parts will fail. Wheel bearings are constantly being exposed to water, dirt and heat – all enemies of even the best engineering designs.
A ritual that is performed at least on an annual basis with our towable is inspecting and repacking the wheel bearings. Thankfully, two newer wheel-bearing styles used in the RV industry make this annual maintenance item a lot easier – and less expensive.
The Nev-R-Lube bearings, such as those on Dexter Axle products, provide a sealed bearing system that Dexter guarantees for 100,000 miles. Periodic inspection of the bearing end play and signs of rust or leakage should be performed. If the bearing looks suspicious, replace it with a new sealed unit.
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The E-Z Lube System is perhaps the most common wheel bearing system being used on modern RV towables. Both Dexter Axle and LCI provide this bearing system to the RV industry. E-Z Lube bearings are identified by a small, black rubber cover in the center of the dust cap. When the black rubber cover is removed a “ZERK” style grease fitting will be revealed.
Our towable uses the Dexter E-Z Lube 7,000 pound rated axles. The design is similar to axles of both a lower and higher weight rating so the method of servicing the bearings is identical.
If you are going to do the job yourself, you will need a few basic tools. Here you can see my pneumatic impact wrench and grease gun. Also, a heavy-duty hydraulic bottle jack and the usual safety equipment such as eye protection and Mechanic’s Gloves. You can accomplish the job with conventional hand powered tools but it will take a lot more effort and time. You are going to be purging a significant amount of old grease from the bearing assembly by adding new grease from the grease gun. I typically use three full size grease gun cartridges when I service all four of my bearing assemblies.
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Using the pop-off cap in a wheel center cover is a no-no.
Select ONLY a premium grease cartridge designed for the extreme pressure and heat generated by wheel bearings. Lithium and moly based grease products both do well, but it is best not to mix the two. IMHO, the better choice is a synthetic grease such as Mobil 1. Yea, it will cost more than conventional grease, but it can endure much higher temperatures and pressures. The difference could be making it to your camping destination or sitting on the side of the road waiting for a tow truck.
The pop-off caps in the center of some wheels might make you think that you can do the job without removing the wheel. Think again! We want to do the job right, not just make a mess. The entire wheel needs to come off, exposing the brake drum and bearing dust cover..
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Remove the metal dust cover from the center of the brake drum by gently tapping around the outer edge with a rubber mallet. Using a metal hammer or making hard blows will dent the cover – which is undesirable. Once the cover begins to break away from the drum by tapping you can insert a screwdriver in the gap and pry the cap off.
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With the dust cap off you will be confronted with a ZERK grease fitting and a lot of dirt and grease. ALL of the surface grease from inside the dust cap and front of the wheel bearings should be removed. If you see any rust you should stop and disassemble the bearings for a through inspection and possible replacement. Disassembly is not part of this article’s text and will require further reference to do the job right.
You are going to end up with a significant amount of old grease – too much to just throw in a trash can. Consider containing the old grease and taking it to a recycling location.
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Place the end of your grease gun over the ZERK fitting – being sure to clean off the fitting first. Your grease gun fitting will “click” onto the ZERK fitting. If you have a flexible hose on your grease gun it is best to hold it in place with a spare hand so it will not pop off. If a solid metal extension is installed on your grease gun you should not need the second hand. The objective now is to pump in new, clean grease and force out all of the old grease. NOTE! This is not just adding a few squirts of new grease to what is there. We want to replace all of the old grease with new product. You will have a huge pile of old grease falling onto the ground below – have something underneath to catch the used grease. If you are using a hand pump grease gun be prepared to make a lot of manual strokes to clean out the old grease. Watch until you see new grease appear (may be a color change depending on grease selection) and then pump some more. Remember, the objective is to replace all of the old grease with new material.
You should now spin the drum to distribute the grease evenly inside the bearings and hub. Add a couple of more shots of grease to fill any possible air pockets and replace the dust cap carefully using the rubber mallet to drive it on tightly.
Remember to use a torque wrench to set your lug nuts to the proper specification once the wheels are back on and resting on the ground.
Easy, isn’t it?
HAPPY CAMPING TRAILS TO ALL!
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Howdy Randy,
That was a very thorough lesson, thank you!!!
I can vouch for the need to maintain those bearings, and if you can’t do the work yourself, find a technician you can be sure you can trust. My 5th wheel was just a year old when we had a bearing failure. Prior to leaving on a cross-country trip (New Jersey to California and back to New Jersey) I had my dealer inspect and repack the bearings if repacking was needed. On the return portion of the trip, along I-95 in North Carolina, my wife noticed in her sideview mirror that something dodn’t look right at the back of the trailer. We stopped and found that the rear wheel on that side was gone. All that was there was the end of the axle. No wheel, no brakes, no bearing, no nut. There was also substantial damage to the side of the trailer, apparently done when the wheel came off.
To make a long story a bit shorter, we were stuck at a motel in NC for two and a half weeks while a replacement axle was found and ordered. I asked the shop to pull the wheels and inspect the bearings on the other axle and they found one badly damaged and the other very dry. After the axle was replaced along with the bearings on the other axle, we brought the trailer directly back to the dealer to have the body work done, and had a “discussion” with the service manager about the bearing inspection they had done. He took no responsibility for the apparently shoddy workmanship. Needless to say, I now have my service done at a different shop. I’ve also learned to check for heat on the wheel hubs every time I stop. In fact, I picked up an infra red thermometer to check the temps, and so far, no problems.
Lew wrote: “I picked up an infra red thermometer to check the temps”
The IR thermometer is an excellent idea – thank you for the added tip!
Hopefully, other readers will heed our advice. It is a poor state of affairs when you can’t trust your service center to properly do the job they are paid for.
Randy
Yikes, that didn’t sound good but I guess from reading this people will try to avoid this
What happens to the grease that comes out of the inner bearing? Where does that go, onto brake drum, ruin seal? Thanks
I went to their site and see that the grease is supposed to make a circle and come out the outer bearing. Thanks again,