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Old 04 August 2008, 17:01   #1
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Shortest wheel bearing life.....

Replaced inner and outer bearings (incl shells), oil seals etc and re-packed with lucas xtra heavy duty wheel bearing grease (the blue / green stuff). I then towed the trailer for 100 miles, topped up the bearing savers and launched and recovered 4 times on a camp site, washing the hubs out each time. Did a quick check and one wheel was rumbling! Bearing was badly pitted and worn - under 2 weeks old!

It is possible the oil seal failed I guess but I was shocked at how little it lasted! Thanlfully I had a couple of spare sets so replaced and re-packed. The other side was perfect with no water ingress. The stud part looked fine with no corrosion where the oil seal fits so I don't think that was the problem!

Outer bearings are fine due to bearing savers but looking at design of hub (M&E axle) I do not think it is possible for grease to migrate from outer to inner bearing!)
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Old 04 August 2008, 17:09   #2
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What method did you use to pack your bearings?
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Old 04 August 2008, 17:34   #3
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large glob of grease in palm of hand and basically push it up through the bearings (wide end down) till it comes out the top of the bearing race (so bearing is fully packed). What I didn't do was completely fill the cavity before pushing the oil seal on (various forums recommended not to do this with scare-mongering of bearings overheating with too much grease), but did put a fair amount of grease in gap between oil seal and bearing.

Both sides done the same and only one side had the problem.

Incidently, when I replaced the bearing and re-packed, I put as much grease in as possible so it was squirting out when pushed the oil seal in. Bearings cool after 100 miles.
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Old 04 August 2008, 18:16   #4
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Your method is spot on. I can only guess it was a faulty bearing or you unknowingly got some grit in it.
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Old 05 August 2008, 18:16   #5
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It doesnt take much in the way of a metal filing to rub a bearing surface and cause it to pick up,.. and then it just starts to self destruct, not common but it does happen, especially if it took force to push those 1st sets in
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Old 06 August 2008, 03:27   #6
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(various forums recommended not to do this with scare-mongering of bearings overheating with too much grease),
Well that's a first! How do they reckon that's going to happen then? Not calling them liars, but interested in the theory!
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When a boat looks that good who needs tubes!!!
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Old 06 August 2008, 08:07   #7
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Changed in it's usual parking place? As Bigmuz says, doesn't take a lot to kill a bearing. Grease sticks to dust & grit like the proverbial bown stuff to a blanket........ I wonder - one badly timed gust of wind threw a small bit of grit in as you packed the bearings? Or did your hand get contaminated? Was it the first or second one you changed that failed?

As for the overheating story, it melts and basically squirts out the seal. On my dinghy Combi (unbraked hubs) I always spent three or 4 trips cleaning grease off the back of my wheels after I changed bearings - when it stops spewing grease, I know the correct quantity is in there! (and it then runs for another 10,000+ miles with no issues) Granted those bearings don't go swimming.

The good thing about this story is it's the perfect example of why you should always carry a spare set of bearings with you........
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Old 06 August 2008, 11:50   #8
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What I didn't do was completely fill the cavity before pushing the oil seal on (various forums recommended not to do this with scare-mongering of bearings overheating with too much grease),
???

As far as I am aware, the more grease you get in (and conversely, the less air you leave in) the better. Not sure a) what "too much grease" would mean, nor b) how that would cause a bearing to overheat.

Did the grease appear to be milky or creamy? If so, water got in somewhere (usually through the grease seal, though the dust cover/bearing buddy is a possibility as well.) Salt water, even when mixed in with grease, will do a number on the bearings in no time.

If not and the grease appeared normal, I'd suspect some contamination (sand, dirt, metal shavings, etc.) got in with the grease (though I'd also suspect that it had to be a lot of crap to take it out that quickly.)

One thing to be careful about is the use of bearing savers: Pumping grease in is good, but pumping in too much may invert the grease seals on the inside and allow water ingress. You should pump the grease in until the spring loaded flange *almost* hits its stop. Don't go nuts and pump grease in 'til it oozes out somewhere (unless you have spindle-lube type hubs.)


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Old 06 August 2008, 12:37   #9
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Does anyone do solid phosphor bronze or olite bearings for trailers? Has anyone tried it? I know they are a lot of work but so ball/taper bearings on a boat trailer!!!
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Old 06 August 2008, 12:54   #10
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Well that's a first! How do they reckon that's going to happen then? Not calling them liars, but interested in the theory!
Cookee, my understanding is that a full bearing is working as a grease pump and so the temperature rises. With thick grease it can get worse because the wedge of thick grease in front of the roller may be sufficient to prevent the roller turning and so it skids around the track further increasing heat and it may burn the grease local to the roller.

Having said that, on a boat trailer which is immersed in water, I reckon filling the whole bearing housing is the only option.
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