View Full Version : Trailer bearings

08-26-2003, 03:47 PM
I have a 2003 mobius w/tandem axle boatmate trailer w/disk brakes on one axle. I dont know if its always been this way, but I just recently noticed that the bearing cover on the rear axle sticks out about a 1/2 inch more then the front axle cover. I can push the it in a little bit, but it springs right back out again. I only have about 1000 miles on the trailer. Is this normal?
Any comments or comparisons would be great.

08-27-2003, 12:36 AM
I think yours is the same as our 99. I have a single axle and had the same problem side to side. See if this helps...

The cap clips into a blue plastic sleeve. The sleeve is spring loaded. If you can push the cap and it moves in or rocks, then there is grease and things are good.

They are supposed to stick out to show a quarter inch or so of the blue sleeve. The cap itself can be pried-off with a little screwdriver to reveal a grease fitting. You inject a little bearing grease with a gun every once in a while to keep whe sleeve sticking out.

The concept is to always keep the bearings under slight positive pressure --- that way water and sand will not be able to enter the bearings. This extends the life of bearings. Should be the same set-up on on all four axles. They should hold pressure for a while. If one goes down, you pump it back up....but not too much ---- don't want to blow-out the hidden back seal.

This website will tell you more about the set-up. I had to study it a while.


On mine, the inner seal went bad on one wheel. This meant I could never get the cap and sleeve to stay "out" for more than an hour or so. ( After filling, you turn your back away and the thing would sink back in ). You should be able to fill it and it stay out for several weeks or longer. They will leak a little at the sleeve and get grease on your rims, but that's the way they work. You want them to leak onto the rim, not out the back seal.

When they leak out the back seal, especially with drum brakes, the grease completely fouls the brakes ( they will not engage at first, then could grab and lock --- dangerous ). Plus, the positive pressure concept is violated and junk can get into the bearings.

Last Friday night I replaced the back seal, and had to replace the brake shoes also cause they were completely saturated with grease. Towed four hours on Saturday, and four more on Sunday ---- caps are still out.

(Its really, really bad to have trailer bearings fail on a long trip....you'd much rather run out of gas or have a flat tire than have to deal with bad bearings on the highway. Especially these Boatmate trailers --- you'll never find replacement parts for these in the middle of nowhere on a weekend.

Its a pain in the butt to maintain these things, but if you think you MIGHT EVER someday take a long trip with the trailer, being a fanatic on the bearings is advisable.)

08-27-2003, 01:12 AM
I've got an 03 Mobius as well, only I have the single axle trailer with disc brakes. Yours didn't come with the sealed oil filled bearings? I just assumed they were standard on the new trailers.

08-27-2003, 11:53 AM
Yes I have the sealed oil filled bearings. What Catdog is saying sounds like it could be the problem if I had grease filled bearing, but I have oil filled, so I dont know if they would have the same results.
I sent an e-mail to Boatmate and sent them a couple pics of my hub assembly, I'll see what they have to say and post the results.
I also attached a couple pics at the link below.

08-27-2003, 07:04 PM
Wow, guys.

Went to sleep for a few years and the technology completely changed on me!

Would like to know how the oil-filled set-up works.

Well, maybe my diatribe will help somebody!

Rip Van W. Dog I

08-28-2003, 01:01 AM

I don't think you fell asleep for very long. I think this is probably the first year they're offering the new bearing setup. Someone correct me on that if I'm wrong, that's just the impression I got from my dealer.

The new bearings have a cover on them that sticks out and looks kind of similar to the hubs on a 4wd truck. There is a sight glass on the end so you can see the oil level in them and they're filled with a 50W oil. The hub also has an allen bolt that can be remove to add oil to them if needed or drain them. My understanding is that they maintain a slight internal pressure that keeps them sealed. Very low maintenance and not more grease getting slung all over your wheels.


Does the tandem axle trailer have breaks on both axles or just one? If it's just one that may account for the difference in how far they stick out.

08-28-2003, 10:43 AM

That may be the difference, I do only have disc brakes on one axle. I'll keep researching, but I hope the answer is as simple as brakes -vs- no brakes.

09-08-2003, 08:19 AM
Have you heard back from boatmate on this? I have a 2003 single axle trailer and the plastic cover on mine sticks out about 1/2" on one side but is completely flush on the other so I'm wondering if I have a problem with one side???

09-08-2003, 12:07 PM
I talked to Boatmate by phone, they told me that the cap in the center of the hub should be about flush with the metal housing, they are made to expand (stick out) a little when they get warm from traveling, but are to go back in as they cool.
2 of my 4 hubs stay out all the time. They told me that the spring assembly must not be working correctly. They sent me 2 new end cap assemblies (no charge), I could either install them myself or have my dealer do the work (under warrenty), I'm going to have the dealer do the work so that if this continues to be a problem I have a paper trail to show the work was done by a "professional".
I was told it will do no harm to still use the trailer as long as there is oil in the hubs (which can be seen through the transparent hub cap)
Sounds like you may have the same issue
I dont have there phone# at the moment, but you can go to the Boatmate web site to contact them. They were very easy to work with and got the parts sent to me right away.

09-08-2003, 12:52 PM
Thanks for the respone, I'll contact boatmate; sounds like i have the same issue you do. Sounds like this could be a re-curring issue for the 2003's. A guy picked up a mobius two days before I picked up mine blew out a bearing on the way home, luckily he had a tandem axle trailer. The dealer checked all the boats that were delivered at the same time for this problem. Has anyone else had any issues with the oil filled bearings?

09-08-2003, 04:17 PM
I had a leak in the hub assembly on the starboard side wheel on my '03. Took it to the factory at Boatmate and Jerry fixed me up, had to replace the whole assembly, and refill. Your right about easy to work with though, no questions, no hassles, just fixed it right up.