Axle bearing question
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I am about to change the rear wheel bearings on my WR250 Husqvarna and I am after opinions as to which way to orient the lip on the seals. Working in the mining industry I rebuild machines that must endure the most severe conditions and years ago I was instructed by an Engineer in the Pilbara to fit seals to bearings in housings with the lip (spring side) to the outside as it was more important to keep moisture and dirt out than it was to keep the grease in. Not possible when with such things as gearbox oil seals as the oil will come past the seal. I have not looked to see which way they are currently fitted but my guess is the lip faces in. 

 

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Never heard that trick before.

Im always lip in.

If you install them backwards on a wheel often the wheel spacers will not fit correctly

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With the spring facing outwards it will get wet and rust loose it's springiness and then snap before your very eyes . In some applications in industry your engineer is correct - not on a axle on a bike . A bit of waterproof grease on the spring with it facing inwards will see the spring last longer than the rubber like it's supposed to.

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It wont make much difference to me as I dont ride that often or far. When I install seals arse about in certain kinds of pump I always pack the spring groove with Coppercote and this seems to protect the spring from corrosion. 

Sadly I wont be doing it this weekend as the bearings and one seal in the All Balls kit I got are right but the other seal is the wrong size.

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Contact seals

Radial shaft seals are contact seals that are used, above all, for sealing oil-lubricated bearing arrangements.. These ready-to-mount elastomer sealing components normally have a metal reinforcement or casing. The sealing lip is usually a synthetic rubber and is normally pressed against a counterface on the shaft by a garter spring. Depending on the seal material and medium to be retained and/or excluded, radial shaft seals can be used at temperatures between –60 and +190 °C.
The contact area between the sealing lip and counterface is of vital importance to sealing efficiency. The surface hardness of the counterface should normally be at least 55 HRC and the hardened depth should be at least 0,3 mm, the surface roughness to ISO 4288:1996 should be within the guidelines of Ra = 0,2 to 0,8 μm. In applications, where speeds are low, lubrication is good and contamination is minimal, a lower hardness can be acceptable. To avoid the pumping action produced by helical grinding marks, plunge grinding is recommended.
If the main purpose of the radial shaft seal is to prevent lubricant from leaving the housing, the seal should be mounted with the lip facing inwards (fig 9). If the main purpose is to exclude contaminants, the lip should face outwards, away from the bearing (fig 10).

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I trust the idea that the engineers at every car, truck , bike and trailer manufacturer know what they are doing when they all put the spring on the insides of their stub or full axles that are lubricated with good old grease.
Btw I read that literature over twenty years ago whilst working in a electric motor shop where would rebuild anything and everything that had a copper winding in it that consumed electricity. From a coffee grinder to a 1mw motor. Warman Submersible pumps heenan variable speed drives... All the fun stuff.
If I recall correctly we would put radial lip seals in with spring outward facing on motors that were installed in corrosive atmospheres to prevent the corrosive gas entering the motor and eating the insulation on the windings . And yes coppercoat the spring.

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