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Thread: 1978 R80 front wheel bearing

  1. #1
    Nick Kennedy
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    1978 R80 front wheel bearing

    Hi Gents
    With 44,000 on the odometer I think my front wheel bearings are going bad. At low speeds with the engine off coasting down my hill I can feel in the bars and hear a dink dink dink sound. Sounds and feels like the bearings are loading up and then letting go.
    If I put on the front disc brake even a little the sound and feeling in the bars stop.
    The wheel is tight with the grab the fork and wheel and push pull test, I really wonder if it is the bearings.
    Putting the bike up on the stand the wheel turns real nice, no noise or sign of trouble.
    But what else could it be?
    That said I read that I need a bearing puller to get the bearings out. Do I need this puller and if so can I borrow or rent one from someone please.
    Or can I heat the hub and tap them out and new ones back in with a drift. I have not been in there yet and don't know what it looks like and the Clymer book is vague. And reading Snowbums site about changing the bearings and setting the preload on this 78 is also quite confusing.

    Any advice on this problem is welcome!
    Thanks in Advance
    Nick Kennedy

  2. #2
    Administrator 20774's Avatar
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    This forum posting is for Snowflakes but basically should apply to the hubs on your spoked wheels (I assume they're spokes):

    http://www.bmwmoa.org/forum/showthre...ent-Snowflakes

    My /7 spokes wheels used heat to tap out the bearings...no special puller needed. It's a bit tricky heating the hubs and getting the bearings out...done wrong, you can do some damage.

    Read the above thread for good info.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
    Nick Kennedy
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    Kurt

    Thanks for that awesome link to Mike V's picture book on how to change out bearings.
    After reading that I feel very confident to do this procedure.
    Nick Kennedy

  4. #4
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    If your hubs are solid aluminum, then you definitely want to heat the hubs to expand the aluminum (aluminum expands faster than steel) so that the outer race of the bearing can be pushed out (or carefully punched with a good punch) from the opposite side carefully. You don't want to get the race "twisted" but want it to press evenly so as not to mar the inside surface of the aluminum which is soft.

    If you have a wheel where the hub has a built in steel center, as my snowflake does, then you do not need to use heat, but it still helps to expand. Press out from opposite side and be sure to support the hub opposite the force so as not to put tension on the rest of the wheel such as spokes or rim. A local machine shop (be sure to explain to them the process, don't assume) may have what is called a "Dake Press" which makes the whole process a piece of cake.

    Also, any time you use heat be sure to heat evenly and do not concentrate in one place. Keep source of heat moving and even.

    Even though these are standard bearings and seals, available at any local bearing supplier (like Applied Industrial, or Bearings Inc.) I found out that they are actually less expensive from Max's BMW!

  5. #5
    Registered User jad01's Avatar
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    It might be a good idea to remove the front wheel and pull the bearings to inspect them. They likely would benefit from cleaning and fresh grease. The front ones are easy to pull apart and inspect by removing the grease caps/seals on the hubs once the wheel is off of the bike. Once you have everything clean you can inspect the bearings and races for pitting or galling. I'd be surprised if they needed replacement at that low mileage unless they have gotten water into them.

    The noise you describe could be the brakes (probably a slightly out of true rotor rubbing the brake pads, or maybe some glazing on the rotor, or possibly a caliper that is not allowing the piston to retract fully and needs to be serviced, etc.). One of the clues is that the noise stops when you apply the brakes... I'd be thinking in that direction myself.
    Jim
    '78 R80/7 and '84 R100RS (Blues Brothers), '86 K75C (Icy Hot)
    '90 and '93 Mazda Miatas (Jelly Bean and Red Hot), '02 325ci (Blue Streak)
    '96 Giant Upland (big Kendas & freshly greased bearings!)

  6. #6
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    Quote Originally Posted by jad01 View Post
    It might be a good idea to remove the front wheel and pull the bearings to inspect them. They likely would benefit from cleaning and fresh grease. The front ones are easy to pull apart and inspect by removing the grease caps/seals on the hubs once the wheel is off of the bike. Once you have everything clean you can inspect the bearings and races for pitting or galling. I'd be surprised if they needed replacement at that low mileage unless they have gotten water into them.

    The noise you describe could be the brakes (probably a slightly out of true rotor rubbing the brake pads, or maybe some glazing on the rotor, or possibly a caliper that is not allowing the piston to retract fully and needs to be serviced, etc.). One of the clues is that the noise stops when you apply the brakes... I'd be thinking in that direction myself.
    My front wheel bearing were toast just after 38,000 miles!

    I just purchased the bike last Christmas but when I tore the wheel apart, I saw that the previous owner(s) hadn't serviced them. It appeared t0 me that they never had been greased - probably only at the factory when the bike was new. Not a drop of lubricant in there at all! My wheel when I spun it, sounded like a bunch of washers being shaken up in a bag - and not all the time either! The sound "echoed" up the forks and even sounded like it was coming from the front fender mount or up at the triple crown somewhere.


    Check them!! Remember your front wheel can't roll with froze up bearings, and if that would happen at 70 mph it could be disastrous!

  7. #7
    . AntonLargiader's Avatar
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    I have seen so many bad bearings lately that I clean & grease the bearings on every wheel that I don't know the history of. Many of these old Airheads only get new tires every decade or so, and it can end up being a really long time since the bearings were last serviced.
    Anton Largiader 72724
    largiader.com bmwra.org

  8. #8
    Benchwrenching PGlaves's Avatar
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    To pull any interference fit bearing heat is almost always good. I can't think of any reason, short of melting some old tired dried up grease not to heat the hub to pull a bearing. But as always, I could be told otherwise by somebody who knows better.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  9. #9
    Mike V. #30064 30064's Avatar
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    Nick,

    Happy to hear my link has been helpful.

    After many bearing jobs since my initial post I've adjusted and refined some of my procedures. I'll mention them just to throw out some possible dialogue. First is; I no longer use the 0.05mm shims for preload. I've acquired many different sized wedding bands to make the final adjustment. A lengthy discussion with Oak convinced me not to include them in the procedure. If you do decide to use them, I strongly suggest you make a clear record in your notebook how many and where. They can be very stealthy to you or anyone other than yourself who services the bearing stacks in the future and misplacing or losing them can be possible - and hazardous. I'm now performing the preload with the wedding bands only. You can chose for yourself to use them but I recommend you keep records if doing so.

    I tend to agree with Paul with heat, even with the steel inserts. I don't apply the same amount of heat to the steel insert snowflakes as I do the notorious rear all aluminum drum rear. But I've found heat greatly enhances the procedure for installing new outer races. I've never liked using hammers with any amount of force.

    Additionally I've developed a feel for the preload adjustment. Based on several pull scale exercises. The pull scale procedure may seem to be like belt and suspenders to some but it's taught me the correct feel for the tension that is preferred. It's a lengthy procedure and requires some special tools but is important in my opinion for the inexperienced and developing the baseline.

    One other thing ... don't forget to change your grease seals annually during cleaning/repacking and check the condition of your top hat spacers for wiper wear.

    -Mike V.
    Mike V. / San Diego
    gruntyman66 MOA#30064
    78 R100/7 [orig. owner] / 81 R65 [restored]
    ABC-MOA-AMA / http://tinyurl.com/4df7hgs

  10. #10
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    Quote Originally Posted by 30064 View Post
    Nick,

    Happy to hear my link has been helpful.

    After many bearing jobs since my initial post I've adjusted and refined some of my procedures. I'll mention them just to throw out some possible dialogue. First is; I no longer use the 0.05mm shims for preload. I've acquired many different sized wedding bands to make the final adjustment. A lengthy discussion with Oak convinced me not to include them in the procedure. If you do decide to use them, I strongly suggest you make a clear record in your notebook how many and where. They can be very stealthy to you or anyone other than yourself who services the bearing stacks in the future and misplacing or losing them can be possible - and hazardous. I'm now performing the preload with the wedding bands only. You can chose for yourself to use them but I recommend you keep records if doing so.

    I tend to agree with Paul with heat, even with the steel inserts. I don't apply the same amount of heat to the steel insert snowflakes as I do the notorious rear all aluminum drum rear. But I've found heat greatly enhances the procedure for installing new outer races. I've never liked using hammers with any amount of force.

    Additionally I've developed a feel for the preload adjustment. Based on several pull scale exercises. The pull scale procedure may seem to be like belt and suspenders to some but it's taught me the correct feel for the tension that is preferred. It's a lengthy procedure and requires some special tools but is important in my opinion for the inexperienced and developing the baseline.

    One other thing ... don't forget to change your grease seals annually during cleaning/repacking and check the condition of your top hat spacers for wiper wear.

    -Mike V.
    Heating hub on dis-assembly is helpful, but I don't see how you can remove the first outer race without doing some "tapping" with a punch (block of hard wood?) and hammer. The second one is easier and you should use a deep well socket appropriately sized and a mallet.

    Removing is only necessary IF the bearings need to be replaced, then replace as a unit. If they do not need replacing, don't remove outer race.

    Assembly is much easier with heat on hub, but it is also useful to freeze the outer race and take out of the freezer just before assembly. Some people (machine shops, etc.) use dry ice to keep a part frozen to shrink it. To tap it in, if necessary to tap, is to use a socket that has its outer diameter just slightly smaller in diameter than the outer diameter of the outer race. Never use the inner race to press in the outer race!

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