XK150 Replacing front hub grease seals
   How to fit

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During a routine check under the car early in 2018, I noticed that grease from the left front hub was visible on the inside of the wheel rim. It was clear that it was time to remove the front hubs and replace the grease seals. It seemed like this task would be fairly routine, but not so ...

On dismantling the left hub, I found the felt seal looked in good shape. After removing the right hub, I found the most of the seal was missing!

front seals left and right

Yet it was the left wheel that had the grease on the inner rim. I know I had not greased the front hubs since I had owned the car. But I could not work out why the left hub was releasing grease. I am still wondering ...

The other strange thing I found when I pulled off the left hub was that the left seal shield was loose - it was not an interference fit in the hub's recess. On the other hand, the right seal shield was static in its hub recess, but it had not been fully inserted and it was a little proud of the hub's innermost face over about half its circumference. Perhaps it was a knife-trimming action on the felt seal over time as the hub rotated, that resulted in the remnant as visible in the photo above.

Here's how I assembled the felt seal and the seal shield ...

(In my case, I was replacing the bearings as well. I had an expert remove the old cups and fit the new bearing cups in the two hubs. I also found that the left stub axle was worn at the inner cone landing area and needed replacement - see stub axle removal tool here.)

First, buy new felt seals and new seal shields.

Ensure the inner edge of the new turned-up shield rim is perfectly smooth and there is no sharpenss or a 'catch' of any kind which might cut the felt seal as the hub and shield rotate. Second, make sure the felt seal mating surface of the axle carrier is perfectly smooth and clean, then add a film of high temp grease.

The steel seal shield should be an interference fit in the hub recess. In my case, the new shields were a 0.4mm (16 thou) interference fit in the hub recess.

After placing the grease-coated inner bearing cone in the hub, test the shield concentricity by placing it lightly on but not in the hub recess. In my case, the hole in each shield was off-centre by nearly 1mm (40 thou). See the photo below.

It's (another) long story, but I had no option but to buy another pair of seal shields. The second new shields were concentric.

  shield-as-supplied   

For final assembly, coat the faces and the outer and inner diameter surfaces of the seal with high temp grease, and then place the seal in the shield. Hopefully, there'll be enough 'stick' in the gease coating to hold the seal in place while the hub is pushed onto the axle.

At this point, all is ready to ready to mount the hub on the stub axle. The outer cone should be pre-coated with grease. However, no bulk grease should be applied to the hub or the stub axle. The idea is to guide the hub into place without the felt seal coming into contact with any surface other than where the inner cone slides on. If all is well, the seal should have stayed in place inside the shield, and now be pressed up against mating face of the axle carrier.

Insert the outer cone ... etc etc

Warning - after the hub refit is finished. and driving the car for the first time and getting the brake discs hot, watch for grease from the felt seal area.

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