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Hub oil seal

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This thread is how to replace a leaky hub oil seal - and what a filthy job it is too - especially if you have One Shot in the swivel housings. If the leak is slight, then it's not too bad, but if you have a gusher and the owner has been driving for a while, then it's just plain awful.

What to look for- Small traces of Grease or EP80/90 :P



Slacken the wheel nuts, raise the corner you are going to work on, support it with an axle stand, then remove the road wheel - the grease has got on both sides of the disc and contaminated the brake pads, which will also have to be replaced (an axle set, so both sides)


Undo and remove the 5 x 17mm head bolts from the drive flange, the hub cap, circlip and two shims, and remove it.



Place a jack under the disc and take the weight of it - the top swivel pin bolts have to be removed and if you don't support the hub - it'll drop down and leak/damage the ball seal.


Now remove the two 17mm head bolts that secure the brake pipe/hose bracket to the top of the housing, carefully slide the bracket rearwards to clear the backplate.



With the bracket out of the way, replace one of the bolts and then remove the jack.

Remove the split pins from the caliper retaining pins, then remove the pins, lever the pads out a small amount to release any residual pressure/clear the rusty lip of the disc, and then remove them.


The caliper is held in place with two 13mm spline head bolts which are usually very tight. Tap the socket on and remove them.



The caliper can be removed and rested on the hockey stick out of the way. Use a cable tie to prevent it from dropping off.


Wheel bearing nuts next.

Bend back the tab washer, then remove the first nut. Lever the tab washer off and then remove the second nut and finally the thrust washer. The tab washer can be re-used if it's not damaged, but make sure the bends in it are in a different place when you re-fit it.







The outer bearing will most likely come out. If you plan to re-use it - wrap it in a rag and put it to one side.


The hub/disc assembly will now slide off the stub axle and the cause of the leak is evident - the seal has for some reason come out of the hub and allowed the grease to leak out.


The hub was just as bad (forgot to take a picture :( ) it must be cleaned very carefully to prevent further contamination of the brakes, etc.


Looks a lot better all cleaned up :)


The reason the seal came out - it's a very loose fit in it's housing (it's also a different shape to the two available types, so I assume it's another, rubbish make). I could easily fit it in the hub and lift it back out again - it should be a tight fit.

The replacement seal is part number RTC3511, which will also replace the earlier type.



Grease the stub axle and seal land.


Coat the inner bearing track in grease, then the bearing. Put the bearing in the track, fill with more grease, then press the seal in nice and square. This type of seal has to be pushed in as far as it will go so that the second lip doesn't rub against the back of the stub axle.





Grease the outer track and then the hub assembly can now be refitted on the stub axle.


Pack the outer bearing with grease and put it on.



Replace the thrust washer, then the first nut. Tighten it and turn the disc at the same time until you feel the disc starting to bind on the bearings. Slacken off a small amount until the disc turns freely with some resistance. Replace the tab washer and then the second nut - tighten it hard against the washer, then bend the tab washer backwards to lock the inner nut, and outwards on the opposite side to lock the outer one.





Replace the drive flange, shims and circlip, hub cap, caliper (use thread lock on the bolts), etc. Place the jack under the disc as before, remove the bolt and replace the brake pipe/hose bracket - making sure it slots into the backplate, and then replace the two top pin bolts. Don't forget to top-up the swivel housing to replace that has leaked out.

Press the brake pedal a couple of times to settle the pads, and it's now ready for the wheel to be put back on.



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FROM Mark90:

A little tip to do to make this job a bit easier: Cut the top of the brake hose bracket so instead of a round hole it is a kind key hole shaped. Not the best photo, but it's all I have....


Then you don't have to undo the swivel pin bolts and all that entails.

Obviously you need to undo the brake pipe to do this mod so something to think about doing when next working on the front brakes.

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