Marine Seals on Camper?

Submitted: Saturday, Apr 10, 2010 at 14:47
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Doing bearings on our camper with drum brakes. I use Castrol APX-T grease and CBC NTN bearings.

Do I need marine seals? Local CBC bloke reckons no, “only for boat trailers, going in the water all the time”.

He reckons also that bearings run hotter with them – which makes sense, but then again is that a problem?

Cheers
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Reply By: Peter_n_Margaret - Saturday, Apr 10, 2010 at 15:25

Saturday, Apr 10, 2010 at 15:25
I have an off road trailer that I fitted grease nipples to the hub caps of.
I completely fill the hub with grease and regularly top them up on the road.
I have heard objections to this practice too, but have never had a bearing failure (or even needed to replace the bearings) since i started to do that (maybe 60,000km of touring?).
Be careful not to over pressurise and push the seals out.

Cheers,
Peter
OKA196 Motorhome.
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Follow Up By: Member - Andrew (QLD) - Saturday, Apr 10, 2010 at 15:34

Saturday, Apr 10, 2010 at 15:34
Is that the same idea as the "bearing buddy" Peter? Pressure is regulated in that case.


Andrew
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Follow Up By: Shaker - Saturday, Apr 10, 2010 at 17:19

Saturday, Apr 10, 2010 at 17:19
Bearing Buddies are just a con, there is no seal on the piston, so how can they seal either grease in, or water out?
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Follow Up By: Peter_n_Margaret - Saturday, Apr 10, 2010 at 18:57

Saturday, Apr 10, 2010 at 18:57
Same idea Andrew, but as you say, the spring pressure is not there (my trailer bearings are MUCH bigger and I can't get 'bearing buddy' style to fit, besides, they stick out toooo far).

Cheers,
Peter
OKA196 Motorhome
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Reply By: Shaker - Saturday, Apr 10, 2010 at 15:26

Saturday, Apr 10, 2010 at 15:26
Why would they run hotter, is he suggesting that wheel bearings are air or water cooled?

The marine type seals are a necessity if you are likely to do any river crossings!

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Follow Up By: jdwynn (Adelaide) - Saturday, Apr 10, 2010 at 19:55

Saturday, Apr 10, 2010 at 19:55
Shaker, he showed me the one's with rubber on the inside face that fit tightly around the shaft, so I just took it that it insulated the bearings. Anyway, it was his theory - I was just trying to understand it. Cheers
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Reply By: Ozhumvee - Saturday, Apr 10, 2010 at 16:35

Saturday, Apr 10, 2010 at 16:35
I use the seals where you tap a stainless ring into the rear of the hub and the seal has two lips, one to keep the dirt/water out and another in beside the bearing (where the seal is normally situated) to keep the grease in. They last for years even under extreme cross country/dirt road use and combined with the APX grease I've never had a bearing failure or indeed replacement for over 200,000k over 20 years on our camper.
Peter
1996 Oka Motorhome

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Follow Up By: Member - G N (VIC) - Saturday, Apr 10, 2010 at 18:34

Saturday, Apr 10, 2010 at 18:34
Hi Ozhumvee

Sounds good, could you tell us what they are called or whom sells them?

regards
GN
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Follow Up By: Ozhumvee - Saturday, Apr 10, 2010 at 19:54

Saturday, Apr 10, 2010 at 19:54
I "think" they were originally a Repco design but they are now available in most places selling caravan/trailer spares.
Bearing kits can be bought which include the seals.
You need to know the diameter of the machined section of the axle behind the shoulder where the rear bearing sits against as the rubber portion of the seal is pushed/jammed onto this section and then runs in the stainless ring that is fitted to the rear of the hub.
Timken sell a kit which calls them boat trailer seals http://www.ntrb.com.au/trailerwbk.pdf

You can also get them on ebay see auction number 380222664149 or for genuine timken 300403142672

Peter
Peter
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Follow Up By: Member - Toyocrusa (NSW) - Saturday, Apr 10, 2010 at 20:55

Saturday, Apr 10, 2010 at 20:55
Hi all. These seals that humvee describes ARE the marine waterproof seals. The secret is to keep plenty of HTB grease in and around the seal, stainless ring, and the rear bearing. This stops the rubber wearing. I also silastic the rubber part to the axle shaft and the stainless ring to the hub, also silastic the front cup to the hub which stops water entering if the hub is hot. I currently have a set on a boat trailer that have been untouched for 6 years after fitting up this way. Had another trailer with the same setup for 7 years prior to this one. Regards,Bob.

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Follow Up By: Ozhumvee - Saturday, Apr 10, 2010 at 21:26

Saturday, Apr 10, 2010 at 21:26
You should not use HTB on trailer wheel bearings or the wheel bearings on most 4wd's, they do not get hot enough to melt the HTB to provide lubrication after the initial grease packing applied.
You should use a lower melting point, sticky grease like Castrol APX or similar.
On earlier Toyota 4wd's the factory suggested normal multipurpose grease, not HTB as you will reduce bearing life due to insufficient lubrication.
Years ago I used HTB and would have to replace trailer bearings after every trip and repack the cruiser wheel bearings as well, after 40k the cruiser bearings would be badly worn. Since using APX and the seals mentioned earlier, for now over 20 years I've never replaced trailer bearings and and usually check and adjust once a year, don't even repack unless contaminated.
Peter
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Follow Up By: Member - Toyocrusa (NSW) - Saturday, Apr 10, 2010 at 21:47

Saturday, Apr 10, 2010 at 21:47
Hi Peter. Not sure I can follow your reasoning there. High Temperature Bearing grease is designed to HOLD its consistency under high temperatures, NOT melt. By doing this it continues to lubricate under all temperatures, low or high. As stated mine have lasted many years and so have all my customers over the last 30. (I work as a mechanic) I dont know why yours would not do the same. Regards,Bob.

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Follow Up By: Ozhumvee - Sunday, Apr 11, 2010 at 07:52

Sunday, Apr 11, 2010 at 07:52
When bought my first cruiser back in 1974 the manual said to use normal multipurpose grease in the wheel bearings, which we did. When HTB came along in the early eighties we started using it but also found that wheel bearings wore much quicker, sometimes after an extended trip they would be badly marked/pitted after just 20k. I had a mate that ran a mechanical workshop and he used to wash the hubs out for me. When he returned the hubs one time in the early 80's he asked how many k's the cruiser had done and I said 40k as we repacked the wheel bearings every 20k as per Toyota recommendations. He then said well you need new bearings as these are buggered, same with the trailer, they would be buggered after every outback trip. He then asked what grease I was using, when I said HTB he then said that is why the bearings are buggered, trailer hubs and most 4wd hubs don't get hot enough to melt the grease sufficiently to allow it to flow into the bearings which means they are only ever lubricated by the initial greasing into the rollers.
He gave me a tin of APX and I've never had to replace a bearing since and only every repack every few years on the cruiser and hardly ever on the trailers.
The main reason I've found for repacking is to replace the worn out seals especially when operating in lots of mud and water as the seals do dry out due to contamination.
I suspect that many later model vehicles probably do run a lot hotter in the hubs due to higher weights, smaller metal mass in hubs etc allowing braking heat to transfer to the hub and in turn the hub but I'll stick with the APX as it has served me much better than HTB plus I don't have to repack very often at all. In fact I never wash the bearings out just put them in the bearing repacker, pump new grease in which pushes the old stuff out, wipe the excess off and stick them back in.
Peter
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Follow Up By: Member - MUZBRY(Vic) - Sunday, Apr 11, 2010 at 08:46

Sunday, Apr 11, 2010 at 08:46
Gday
I do the same with mine Pete.
Murray
Muzbry
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Follow Up By: Member - Toyocrusa (NSW) - Sunday, Apr 11, 2010 at 16:36

Sunday, Apr 11, 2010 at 16:36
No worries guys. If it works for you thats all that matters. Bob.
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Follow Up By: Member - G N (VIC) - Monday, Apr 12, 2010 at 15:34

Monday, Apr 12, 2010 at 15:34
Hi Ozhumvee

thanks for seal info.

I totaly agree with the HTB info, i had same experience and will NOT ever use it again.

regards
GN
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Follow Up By: jdwynn (Adelaide) - Friday, Apr 16, 2010 at 09:49

Friday, Apr 16, 2010 at 09:49
Guru’s, I bought some marine seals. Now looking at the picture there is about 20mm of shaft behind the shoulder (yeah, I know, I have to clean it yet).

Alright, I can see rubber will be tight on the larger shaft section, but is that enough. Uncomfortable about the fact that there’s nothing holding the rubber hard against the stainless ring, and nothing stopping rubber moving back towards drum wall.

I could definitely go with Toyocrusa’s advice re: the Silastic, but is that enough. Just can’t get comfortable about it. Perhaps larger dia shaft section too long on my unit?

Any advice appreciated.

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Follow Up By: Ozhumvee - Friday, Apr 16, 2010 at 17:43

Friday, Apr 16, 2010 at 17:43
silicone will hold it, but if you are worried get a piece of slightly smaller conduit of the length you require to fill the gap, split/cut it lengthwise and it will sit on the axle happily stopping the seal moving away from the hub.
I've always just used silicone without any worries, just let it cure before towing the trailer.
Peter
1996 Oka Motorhome

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Follow Up By: Member - Toyocrusa (NSW) - Friday, Apr 16, 2010 at 19:55

Friday, Apr 16, 2010 at 19:55
Maybe even Sikaflex, (I think that's how it's spelt) It has a greater bond strength. Bob.

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Follow Up By: Member - Geoff A (VIC) - Sunday, May 02, 2010 at 11:28

Sunday, May 02, 2010 at 11:28
I've just done the bearings and seals on our trailer, and used marine seals.
I did look at the issue of the rubber seal maybe moving away from the hub, but decided it wasn't an issue. It's a tight fit on the axle. What will make it move?
It did occur to me that if it became a problem, then perhaps another hub seal could be slid onto the axle (maybe the old one?) to pack out the gap between the back of the hub/seal and the end of the machined stub. Rough measurements seemed to say this would work. I will keep an eye on mine.
Just a thought..........

Cheers,
Geoff
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Reply By: Member - Charlie M (SA) - Sunday, Apr 11, 2010 at 21:56

Sunday, Apr 11, 2010 at 21:56
Should not be a problem, just check to see if there is clearance on any brake parts as sometime they may catch near backing plate.
Cheers
Charlie
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Follow Up By: Member - Charlie M (SA) - Sunday, Apr 11, 2010 at 21:57

Sunday, Apr 11, 2010 at 21:57
they are a two piece seal
Charlie
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