Its just a grease cap. Keeps dirt and road debris out of your grease/bearings. I wouldn't travel too much without it. Wherever you buy replacement wheel bearings should have a cap to fit it. They come in several sizes, most common being 2". You can get them online too at any place that carries axel bearings/parts. https://www.etrailer.com/s.aspx?qry=grease+cap
Part are probably "Grease Cap (Ultrulube)" & "Rubber Cap (Ultrulube)"
I don't know if you actually have an Al-ko axle but a lot of us do that own FR trailers.
About the 3rd or 4th time you pull these grease caps off for bearing service, it gets loose, leaks and I've had one come off inside the wheel cover. I carry a spare.
These two parts are listed in my manual as "Grease Cap - Ultrulube" and "Rubber Cap (Ultrulube)". I replaced mine with the Al-ko Dexter cross referenced part in the attachment Al-ko/Dexter cross reference. They fit.
There are other trade names for similar caps. About a year ago I bought what appeared to be the same part from an ebay seller. Although advertised to fit Al-Ko 3500lb Ultrulube axles, they could not be driven on the hub. They were just a shade too big.
If you have been running without a grease cap for very long, you definitely need to pull the hub, inspect, clean, repack/replace and adjust the bearings. It never hurts to adjust the bearing nut. The bearings can wear, get loose and self destruct.
Most any dealer that sells flatbed, utility or cargo trailers will also sell Dexter parts. They might be unaware that Dexter bought Al-KO US assets so I carry a copy of the cross-reference with me. I had one dealer tell me ".. 25 years in this business and never saw a Dexter part fit an Al-ko axle". He feels differently now.
So...is that an "all stop" kinda problem or something that's "fix it when time allows" problem?
Also, is this something I can replace myself?
NOW! If it was lost on the road, you have already picked up contaminates in the grease. Any dirt or water that gets into your bearings will not make your day. To be safe, I would suggest pulling that wheel, either cleaning and repacking, or replacing the bearing sets (inside and outside), the inner seal, and the outer grease cap. This is very serious. Any dirt particle that would score a race could cause a bearing failure.
We had the same type of outer cap. What we did was to put a set of hub caps on all fours. If one of the grease caps came off, the bearings would still be safe and the grease cap would not be lost. Etrailer would also have your missing outer grease cap. https://www.etrailer.com/Accessories...bur/319EZ.html
"About the 3rd or 4th time you pull these grease caps off for bearing service, it gets loose, leaks and I've had one come off inside the wheel cover. I carry a spare."
Kenh, what I have done over the years when a grease cap gets loose is to take pliers or vice grips and carefully bend the sleeve of the cap out so it fits the hub snugly. The cap metal is pretty soft. I have also been told that a sharp punch can be used on the hub mating surface to provide a better cap grip. Also works for a quasi-loose bearing race. I have scored the seat of a bearing race, but not for the grease cap.
Being the cheap skate that I am, I put a gob of grease in a sandwich baggie, put the bearing in the bag and knead the grease into the bearing. I use the baggie for all of the bearings, adding grease as necessary, then properly dispose of the bag. Ya, there are devices for that, but a baggie works for me and I have nothing to store but the left over grease.
When I do bearings, I replace rather than clean and repack. I have always been concerned that cleaning a bearing may leave a particle that could cause a bearing failure. That's one thing I won't gamble on. Though we carry an extra inner and outer bearing set, an inner seal and grease for one wheel, we have never had a bearing failure or grease leak.
I have always done my own bearings because of back-to-back experiences with two mechanics. Prior to taking a Canada trip, we had the truck in for warranty work to replace a rear axle bearing. The seal was leaking differential oil onto the brakes. The dealer replaced the parts and new rear brakes.
About 150 miles up the road, we exited at the Dells in Wisconsin. Loaded for the trip and a 10.5' slide-in in the bed, we were almost nil in the brakes department. It was on a Friday and there was a dealer with a service department in the Dells. The rear axle bearing had failed and ruined a new brake job-and our trip. The dealer had the parts and got the truck back together just at closing. Great, we were off-until the first right turn in downtown Dells. I lost ability to move. Looking in the mirror, I could see my wheel our past the fender. Panic time!
A police officer happened by and gave me professional courtesy. He directed traffic while I jacked the rear corner up and got the axle shaft seated back into the differential. He then escorted us back to the dealer, but the dealership was closed. He managed to get hold of the parts manager whom was able to get the parts-but not the mechanic. I worked past midnight with DW holding the flashlight to get it back together enough to get back home. I went back to work while the home town dealer got all of the parts to get the truck back together correctly. The vacation went a lot better a couple weeks later.
I like that tip to pack the bearings in a plastic baggy. I usually use my bare hands.
I'm not a big fan of pumping grease in a axle as a substitute for the pulling the bearing, cleaning repacking or replacing. But I will occasionally give them a couple of squirts if I don't have time to pull the hubs and do it the 'right way'. I have never blown out a grease seal but then I'm real careful.
When I bought this trailer I had 2 of the original Al-KO grease caps fall off inside the wheel hub covers after I had pulled the trailer about 6k miles. I check my bearings about every 4-6,000 miles. So, they did not fall off right away. The last time I replaced the grease caps with what were supposed to be original Al-Ko parts and they stayed on for about 19000 miles until two weeks ago when I decided to replace all 4 hubs. During this period I pulled the grease caps off about 3 time I believe to adjust the bearings.
The new Dexter hubs/bearings were adjusted per the book and everything went together fine. I've done this many times before. The Dexter version of the Ultrulube grease caps looked like the Al-Ko grease caps. Every one was good and tight.
This morning I pulled the trailer about 10 miles and came back home to check my bearings. Since it was a test run, I worked the trailer brakes hard, but nothing even close what you would experience during a long descent. When I returned home, I pulled all 4 hub covers off the wheels and one of the 4 Dexter grease caps had fallen off. It was so loose I could push it on and off with my hand.
I did try to bend out the edges of the defective grease cap in an effort to get it to stay on. But it was still loose and could be pulled right off. I've tried bending the edges of these before and even if they stay on, they ooze grease and make a mess of the wheel. I did not trust the failed cap.
It is as though the heat cycle caused the thin metal of this grease cap to weaken and collapse. It is important to note that the other 3 grease caps were still on and tight. There was nothing unusual about the temps of any of the 4 hubs.
It was only a 10 mile cruise. I am beginning to think some of these grease caps are just soft metal and they are definitely not all the same diameter. So sometimes they fall off.
I had a spare Al-Ko original Ultrulube grease cap and installed it on that hub where the Dexter-Al-KO replacement grease cap failed. I'm leaving for a 900 mile trip this weekend. I'll check all 4 grease caps again when I get back.
Take a look at the video. The grease was on when I left and sometime during a 10 mile trip, it fell off.
I like that tip to pack the bearings in a plastic baggy. I usually use my bare hands.
I'm not a big fan of pumping grease in a axle as a substitute for the pulling the bearing, cleaning repacking or replacing. But I will occasionally give them a couple of squirts if I don't have time to pull the hubs and do it the 'right way'. I have never blown out a grease seal but then I'm real careful.
When I bought this trailer I had 2 of the original Al-KO grease caps fall off inside the wheel hub covers after I had pulled the trailer about 6k miles. I check my bearings about every 4-6,000 miles. So, they did not fall off right away. The last time I replaced the grease caps with what were supposed to be original Al-Ko parts and they stayed on for about 19000 miles until two weeks ago when I decided to replace all 4 hubs. During this period I pulled the grease caps off about 3 time I believe to adjust the bearings.
I think I may have discovered what happens with the Ultrulube grease caps. I replaced all 4 hubs, bearings and the grease caps with replacement parts from Dexter.
The bearings were adjusted per the book and everything went together fine. I've done this many times before. The Dexter version of the Ultrulube grease caps were real tight as I drove them into the hubs. Everything seemed to go OK with all 4.
This morning I pulled the trailer about 10 miles and came back home to check my bearings. Since it was a test run, I did work the trailer breaks pretty hard but nothing even close to a long descent. When I returned home, I pulled all 4 hub covers off the wheels and one of the 4 Dexter grease caps had come off. It was so loose I could push it on and off with my hand. I did try to bend out the edges and get it to stay on but it was still loose and could be pulled right off. I did not trust the failed cap. It is as though the heat cycle caused the thin metal of this grease cap to weaken and collapse. It is important to note that the other 3 grease caps were still on and tight. There was nothing unusual about the temps of any of the 4 hubs. It was only a 10 mile cruise. I am beginning to think some of these grease caps are just soft metal and they are definitely not all the same diameter. So sometimes they fall off.
I had a spare Al-Ko original Ultrulube grease cap and installed it on that hub where the Dexter-Al-KO replacement grease cap failed. I'm leaving for a 900 mile trip this weekend. I'll check all 4 grease caps again when I get back.
Take a look at the video. The grease was on when I left and sometime during a 10 mile trip, it fell off.
while taking the entire hub/bearings out cleaning and lubing them is not a bad idea, by correctly lubing the Dexter axle you should have years and thousands of miles of carefree service...
if you follow the video shown here, it will help you to NOT blow out the rear seals and contaminate the brakes... I always jack the wheel and rotate it while pumping the grease
make sure you always use the same grease and don't mix brands or types of grease
__________________ "nothing can now be believed which is seen in a newspaper. Truth itself becomes suspicious by being put into that polluted vehicle." Thomas Jefferson to John Norvell pg. 2, June 11, 1807 2014 Shamrock 183
2014 RAM 1500 Bighorn Crew Cab, HEMI, 3.21 gears, 8 Spd, 4X4 TST TPMS
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