Thread: Boat trailer axle seals

Hello again.

Sitting at Denpasar airport waiting for a flight - might have found the answer on a US Youtube clip.

Basically an extra lip on the outer side to stop water ingress?

Cheers,

The only glitch I have found with them is that on my Campomatic, the rubber bit of the seal does not fully sit into the stainless outer unless you pack behind it with a bit of silastic. I think that it is really essential that the rubber bit sits right into the outer.Also it is important that the rubber bit stays still and the movement is between the outer part and the stainless track, so the silastic also is needed to anchor it to the axle.

It may depend on the setup, but my Campomatic has parallel bearings on an independent suspension.

You can check this after you assemble the hubs on the axle, and just lever it in and dab some silastic behind the rubber bit to ensure it cannot move out.
Regards Philip A

Suggest you may also fit "bearing buddy" type hub caps to replace the usual pressed metal caps.
These allow you to squirt grease into the hub assembly and a spring arrangement ensures there's positive pressure inside the hub to prevent water ingress.

Alan

Originally Posted by Rurover

Suggest you may also fit "bearing buddy" type hub caps to replace the usual pressed metal caps.
These allow you to squirt grease into the hub assembly and a spring arrangement ensures there's positive pressure inside the hub to prevent water ingress.

Alan

Hello and thanks.

It is fitted with buddies - second set since I got it. Some kind soul knocked the originals off at the ramp one day......

I generally check them before putting the boat in, but also note the warning not to overfill the hubs. The left hand buddy seems to get an oily puddle in it when you remove the plastic cover.

Anyway the right hand side hub has a slight rumble when you rotate it, so an overhaul is pending.

Still a bit keen to get the theory of how the marine seal is meant to work - the packets have no details, including fitting instructions.

Cheers,

Still a bit keen to get the theory of how the marine seal is meant to work - the packets have no details, including fitting instructions.

You just whack the outer stainless track into where you would normally fit the seal until the flange is hard on the hub. Maybe add a bit of silastic under the rim. The dimensions of the stainless track are the same as a normal seal.
The inner rubber bit is slipped over the axle onto where the seal normally seals against. It is quite tight on the axle. Add an little grease into the inside of the stainless track and the outer rim . Theoretically the friction of the centre of the rubber on the axle keeps it in position but as I said IMHO it is better to anchor it.
It just works like a seal but is the opposite ie the rubber seal stays still and the stainless bit is the seal track whereas normally the seal moves around with the axle and the track /seal surface is on the axle and stays still.
I found them pretty good for dust and water entry, with only a very tiny amount of dust on the surface of the grease near the inner bearing after a trip around Australia.
I wonder however about Bearing Buddies, as IMHO excess grease could force the seal away from the track unlike standard seals where this is not possible. Another reason to pin the seal with silastic. I only put enough grease in to cover the bearings and the void between I leave empty.

On reflection I think that the seals are designed to "cinch up" when a vacuum is created in a hub like entering cold water with a hot hub,unlike normal seals, as the seal element would be pulled in to the track.

Regards Philip A

Philip,

Hello again and thanks for the added info on the seals - genuinely appreciated.

The back of the packaging of the Timken kits for both the regular and marine seals has exactly the same set of minimalist instructions which are those for the one piece regular seals. To add to it, the instruction just says "fit the seal".......

Clearly, they work quite differently as you describe in terms of what rotates and what doesn't.

Cheers,

Neil

Hello again from Brisbane.

Been working fairly slowly on a range of fronts (Land Rover, mower, house, boat and trailer), but made a little progress on the trailer bearings and brakes over the last couple of weekends fitting in an hour here and there.

Pulled the hub discs off and cleaned up the bearings etc - doesn't appear to be much wrong with the bearings or cones (no rust, pitting or signs of heat) although here appears to be signs that the grease has been pushed past the seals, particularly on one side. Possibly a case of having the hubs overfilled and then over enthusiastic topping up through the bearing buddies:





This one had a lot of grease around the inner rim of the hub.

The brake mechanisms were a bit rusty, but not showing any flaking etc and the bolts were good as new, so I decided to brush them up and apply cold gal and fit new stainless springs rather than buy new galvanised units. Not sure how that will go, but nothing lost in trying:





The pads were stuffed, especially the steel backing plates, so new ones are going back on:



Have to make a decision on the hubs - new galvanised ones are ~$150 a pair, but of Chinese origin. Might be better to get the present hubs machined and paint them with something - suggestions welcome.

Finally, going back to the original question of the bearing seals - the hubs were actually fitted with marine seals rather than the ordinary bearing seals that I thought had been installed by my father-in-law. Memory is a tricky thing and it was about 10 years ago. Interestingly, I noticed that there were 4 small spikes welded on to the ends of the square section of the axle, presumably to hold the axle seal rigid when the hub turns. Not sure if the previous owner did this (he was a retired engineer) or it came like that from MacKays who built the trailer.



So, that's about it for now.

Cheers,

Neil

P.S. a quick question - the galvanised rims have become quite dirty and hard to clean up. I may have exacerbated that by cleaning them with carby cleaner at various stages. I believe you can clean galvanising with various chemicals (e.g. isopropyl alcohol, phosporic acid), but run the risk of damaging the finish with over use, especially with acids. Any suggestions there?