Rear Wheel Bearing Replacement
Rear Wheel Bearing Replacement
Wheel Bearings are probably the most neglected part of any motorcycle, and on the older, twin-shock Boxers the near-side bearing in the rear wheel can totally fail with little warning. Its seal becomes worn by exposure to grit, allowing road grit and water to contaminate the grease. The off-side bearing is well protected within the hub, and like the front wheel bearings, gives little trouble. Always remove the inner races of your bearings every year or so, washing out all the old grease, and re-packing before replacement with new seals. If you ride throughout the winter, re-grease the near-side rear bearing in Autumn and Spring. Remember - new seals are cheaper than bearings! The front wheel bearings of the later Monolever Boxers and K-Series models give little trouble, even after extreme use.
Rear “Wheel Bearings Replacement"
by Kristian #562
15/10/01
While I was waiting for the parts for my Water Pump, I think I turned into a Bearing and Seal fiend. I think replacing Seals & Bearings is almost more satisfying than a new pipe and slippers,
sorry I mean pipe and jets, which is why I'm writing a few things up here. A blowtorch/propane torch is very much the answer for bearings. And a Refrigerator. Replacing the Wheel Bearings really makes me feel good about my bike, especially those crunchy Russian (Yep, Stamped made in Russia) Rear wheel bearings.
General:
You shouldn't need to replace any Bearings at all unless they are worn and crunchy or obviously broken, like a number of my Idler Arm (free) Needle Bearings were. See Feeling for Worn Bearings for a description. What you SHOULD do is regularly Grease them with a good
High Temp Bearing Grease. (You cannot Grease sealed Wheel Bearings btw...)
Some seals, of the same size, like the ones that came out of the idler arm, have a steel rim and rubber centre, while others are all rubber, I really don't know what the difference is in terms of application, however the bearing man assured me it was fine and showed me the numbers were the same, which of course they were.Especially to knock IN the new bearings without damaging them you MUST have a drift just slightly smaller (so it doesn't Jam in the
hole) the size of the outer rim of the bearings, otherwise you will damage the cover plate between the inner and outer race of the bearing. I used sockets that were just the right size, but another good alternative is a thick walled pipe the right size.Put the NEW bearings in the Freezer well before you start and don't take them out until the LAST possible moment. Keep them on water/ice if you need them by you.
Experiences:
97F650 Classic - rear wheel bearing failed catastrophically at 13,000 miles just north of Anchorage, on the way back from a trip to the Arctic Circle. I was refused warranty work by Anchorage BMW dealer, as bearings are a "normal wear item". I've been told that the "service interval" (i.e. remove & replace) is 25,000 miles. Local dealer and BMWNA gave me the royal run around, never resolved (ask me if I'll bother to buy a BMW new enough to have a warranty again). Have had the bike since 7200 miles, my mileage had been (at that point) approximately 15% graded gravel road, the rest pavement (almost all street now). Based on the condition of the bike, I suspect that the previous owner's miles were mostly pavement as
well. Pictures of: Failed F650 Bearing. The metal outer part is all that remains of the seal; the outer spacer (3 o'clock position) is grooved at seal area. The inner race (5 o'clock) is missing the balls and cage (silver dust inside wheel hub). Outer race is still in the wheel, and notice that the inner spacer end is chewed up a bit.
Bearing Dust. This is the material that poured out of the wheel when we dumped it out. Note the lack of indication of any lubricant. When the inner spacer was pulled out, some egg shaped balls fell out as well. Both bearings and the seal were replaced (other parts were not
available). I will be redoing the whole job complete with new parts when I remove that wheel for a new tire/chain/sprocket (soon). Will use standard industrial/automotive bearings (# is in FAQ) and seal, ask for the "top of the line" bearing (forget the name), it's like US$2.00 more/bearing (price was less than $20/bearing, if I remember correctly).
