•  

    Welcome! You are currently logged out of the forum. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please LOG IN!

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the benefits of membership? If you click here, you have the opportunity to take us for a test ride at our expense. Enter the code 'FORUM25' in the activation code box to try the first year of the MOA on us!

     

Wheel bearing repair booklet

I have an 83 80RT with drum brakes on the rear. I have been trying to rebuild the bearings both front and rear. I just realized my local dealer gave me the wrong height "top hat" a few months back. He just read it off the microfiche. From reading posts here, I can't believe how complex is seems to get these simple wheel bearings put together properly. Spacer size, correct torque, top hat in correct position. Now it appears that BMW put about a dozen different top hat lengths in the same model/ year bike. Must be a reason, but I sure would like to hear it. My question is this: I thought I saw some mention of a booklet that was available at one of the international rallies that covered in depth the whole wheel bearing issue for airheads. Apparently because the work is so complicated. Does anyone know if that booklet is still available, and how to get one of the things. I am sure that my local dealer's mechanics will be clueless on the complexity of these wheels, besides the fact that as difficult as they seem to be, I only trust myself to, hopefully, get them right. Thanks to all for the help.
 
Snowbum and Gary Smith had a seminar at the 2004 Spokane Rally. Those that attended got a copy. I'm not aware of them being sold. But you might check Snowbum's website and contact him to see what he'd be willing to work out.

http://bmwmotorcycletech.info/techindex.htm

Your other alternative is to find the articles in MOA News by Gary Smith, all in 2004 - May, July, September, and November.

Hmmm...a dozen different top hats? Are you referring to the wedding band spacers? I actually thought the top hats were all the same, but the wedding band spacers were used to adjust the preload on the bearing stack.
 
John,
Do you have either one of your old rear top-hats? I believe for your rear wheel (cast - snowflake) the left and right top-hats are identical.
Maybe 36 31 1 230 322. I don't know what the exact dimensions are on that top-hat (either 13mm or 9mm maybe) but if you have one of your old ones, measure it. The key is that you get adequate compression on the bearings when the axle and axle nut are secured and torqued. Your wheel bearings on the 83 are actually much less complicated than some of the earlier wheels without the steel hub.

You'll need some special tools, race puller and some axle spacers/collars to determine the preload on the new or existing bearings. All can be had from Dan Neiner at Cycle Works http://www.cycleworks.net/ or other airhead savy shops. We can walk you through this if you want to tackle it on your own.
 
Thanks for the information. I just checked and this is what I have: 1) Drum brake side has no wedding ring, top hat is 9.14mm high. 2) closed side has a 6.75 mm wedding ring, and the top hat spacer is 12.95 high. The top hat that the dealer sold me is 10.79 mm high. (This is the rear wheel. ) My Clymer manual has nothing on the intricacies of what heights go where, bearing preloading, etc. I will be requesting more help from all of you. I will check with Snowbum's site, as you wisely suggest. Thanks.
 
John,

Is there a reason you need to replace the original top-hats? Are they grooved from the grease seal wipers? If not, I would just clean them up and reuse them in their original position as long as they are not damaged. There will be only one wedding band and it is typically on the left side of the innerspacer or hub. You probably noticed a pair of plastic or hard nylon bands on the inner spacer. One of which is extended past the end of the spacer a few millimeters? (attached photo) Keep it in that position, it will help capture the wedding band and keep it in place during assembly. Are we shooting for new bearings and races or cleaning and repacking the existing bearings?

-Mike V.
 

Attachments

  • 81R100RS Whl Brgs Rear D_Jones 2-13-11 006.jpg
    81R100RS Whl Brgs Rear D_Jones 2-13-11 006.jpg
    45.2 KB · Views: 202
Mike,
Thanks for the information and the picture. I checked mine and indeed, it has the same set up you show in the picture, with the center spacer and the nylon pieces, one hanging over the end as you say. I need to re-do the whole wheel, bearings, seals, even the paint. My top hats are a bit beat up, probably as you say, from the seals wearing on them. One was chipped and I thought that might eat at the seals, hence the replacement try. I am reading Snowbum's lengthy articles on pre-loading, etc. I emailed him but it came back undeliverable so I assume he may be out of the BMW buisness. Maybe I am wrong. I am staying at it to try to understand the whole theory of what is inside these hubs and how each piece works for the perfect fit. Thanks again.

John
 
John,

Let's nibble off some small chunks at a time. You say you're going to repaint the wheels? If so, purchase an adequate race puller and let's remove the entire bearing set-up. How does this sound...

Carefully remove the seals and top-hats which I assume you've already done. Keep everything organized being sure to label "left" and "right" and be sure not to mix up the front wheel parts with the rear. Do one wheel at a time. Hopefully you have a quality caliper that you can measure things with. If not, purchase one. My Harbor Freight digital caliper has been a great friend and more than reliable & affordable. A great tool to have in the shop. You may also want to make sketches and take photographs as you go. This can be a life saver. Take your time in a clean, well lighted and organized work space.

After you remove the grease seals the bearing cage (rollers) should fall out. Remove the left seal, top-hat and rollers and mark them or bag them "left". Record the diameter and thickness and number of wipers of the grease seal and record. Don't count on the OEM Fiche for correct seal numbers. You'll have to match these at your local Dealer or give the measurement info to an experienced airhead supplier. I purchase my bearing parts from Tom Cutter at Rubber Chicken Racing Garage http://www.rubberchickenracinggarage.com/. Tom is great and knows this stuff like the back of his hand. Now measure the width of the left top-hat, record and mark or bag it "left". Now do the same for the right side. After you have this done we can remove the bearing races with an adequate puller. The inner spacer will not come out until one of the races are removed. I like to start on the left side. With the left race removed, reach in the hub and pull out the inner spacer noting it's position. The wedding band may be sticking to the inner spacer with grease. Remove the wedding band and put it in your "left" bag along with the inner spacer. Now remove the right side race with the bearing puller. That's it! At this point, I like to wash all the old parts in solvent or acetone so I can carefully examine the old bearings. After everything is cleaned and dried, place back in the appropriate bags. Now's the time to order your new bearings & races (30203A / pn:07 11 1 9 985 005), appropriate sized top-hats that need to be replaced and new grease seals. By the way, these wheel bearings are very common and can be purchased at any auto parts store if desired.

Now - go ahead and get your wheels cleaned, prepped, and painted. During or after your wheels are being painted we can start talking about the installation of the new bearings and preload. You'll need to order or fabricate some appropriate sized collars to slide over your 17mm axle for the preload procedure. Contact Dan Neiner at Cycle Works http://www.cycleworks.net/, or Jeff Trapp for the collars http://www.northwoodsairheads.com/Tools.html, or anyone of your choosing that may have these special airhead tools.

Here's some of my picture links to look at to give you an idea of what to expect. The rear wheel link below is totally different than your wheel and the process for your wheel is much simpler. The front wheel link below is more of what you can expect to find in your wheels. Now's the time to decide if you want to tackle this on your own or outsource. You'll have to do your due-diligence and research along with some special tool purchase but this is very doable with some care and attention. I'll try to help you along in any way I can.

Front 78 Snowflake:
http://tinyurl.com/46jnfyg

Rear 78 Snowflake:
http://tinyurl.com/48ju5lt

Wheel Bearing Tools:
http://tinyurl.com/4oy2mvw

-Mike V.
 
I emailed him but it came back undeliverable so I assume he may be out of the BMW buisness. Maybe I am wrong.

John -

Snowbum's not out of this "business" by any means. He might be a little slower on the response. I will say that he has a series of steps to get through to contact him. When I first contacted him, I had to answer a series of additional emails to "prove" that I was a legitimate perons, etc. Once I ran the gauntlet, my email address is now accpeted by his email program. So, I'd keep trying. If you really need to contact him, perhaps I could pass along your desire to send him an email and you could go from there. PM me if you get to that stage.
 
I have an 83 80RT with drum brakes on the rear. I have been trying to rebuild the bearings both front and rear. I just realized my local dealer gave me the wrong height "top hat" a few months back. He just read it off the microfiche. From reading posts here, I can't believe how complex is seems to get these simple wheel bearings put together properly. Spacer size, correct torque, top hat in correct position. Now it appears that BMW put about a dozen different top hat lengths in the same model/ year bike. Must be a reason, but I sure would like to hear it. My question is this: I thought I saw some mention of a booklet that was available at one of the international rallies that covered in depth the whole wheel bearing issue for airheads. Apparently because the work is so complicated. Does anyone know if that booklet is still available, and how to get one of the things. I am sure that my local dealer's mechanics will be clueless on the complexity of these wheels, besides the fact that as difficult as they seem to be, I only trust myself to, hopefully, get them right. Thanks to all for the help.

I have one of the Books from Gary Smith's Semenar on Wheel Bearings somewhere!

I will get back to you!
 
Wheel Bearing Book

OK I found the book, all 49 pages of it!

I don't want to sell it and it's too much to scan or copy.

Maybe Gary Smith has it on a digital file somewhere!

Maybe if you ask real nice!

Look him up in the Ambassador page.
 
Darryl,
49 pages. Wow! I understand perfectly why you both wouldn't want to part with it, or copy it. I don't think I would either. But thanks for the thought anyway. I'm glad to know it does exist, and better still, that it really does take 49 pages to explain this little job. I always believe that knowledge brings peace of mind!
Mike,
Thanks for all the good info on you posting. I am following the steps you outlined carefully. Very good links, too. Where do you guys find this stuff...? My current dilemma is that a local dealer tells me there are two sizes of top hats used on the brake side (10.7 and 9.2) and no, he had no idea why, or which one to use. And even better, he had a part number for the non-brake side top hat, but it didn't say what size it is. Not a lot of help. I am debating whether to just re-use the ones I have, although they both have some grooving from the seals. I see leaking grease on my new paint, or onto the brake shoes as a possibility. But maybe it isn't that critical. The grooves are slight. Maybe I will call Bob's BMW on the correct top hat size issue. They are usually pretty helpful. Thanks.
 
Darryl,
Not to take up all the space on this thread, but I just noticed that you said you have 495,000 miles on your 77 R100rs. Is that right or are my eyes giving out? I have to say that is one of the most inspiring things I have read on this forum. Everyone asks me why I keep working on my R80. I will file your mileage away for use in future replies to that tiresome question. I am impressed! That's a lot of riding and dedication to one bike.
John
 
My current dilemma is that a local dealer tells me there are two sizes of top hats used on the brake side (10.7 and 9.2) and no, he had no idea why, or which one to use.

Those don't sound like top hats to me...top hats are close-out caps for each side of the bearing stack. Those are the two spacers which are used to adjust the rear wheel relative to the swingarm. The standard spacer is the 9.2mm one. This works with stock size tires and widths. If someone insists on running an oversize or extra wide tire, it can rub on the inside of the right swingarm. Then you use the 10.7mm spacer to move the tire over to the left.

The good thing is that the tire is moved over. The bad thing is that the brake pads run on different areas of the drum than before, possibly chewing up one portin of the brake pad. I suspect that for disk brakes there would need to be some kind of spacer or adjustment to keep up with the movement of the wheel sideways.
 
Darryl,
Not to take up all the space on this thread, but I just noticed that you said you have 495,000 miles on your 77 R100rs. Is that right or are my eyes giving out? I have to say that is one of the most inspiring things I have read on this forum. Everyone asks me why I keep working on my R80. I will file your mileage away for use in future replies to that tiresome question. I am impressed! That's a lot of riding and dedication to one bike.
John

I have 487,500 miles on it and should hit half a million this year!

Bought it in 1986 with 68,000 on it.

Saw a 1977 R100RS in Wyoming with 970,000 miles on it so I have a few more to go /:>)
 
Saw a 1977 R100RS in Wyoming with 970,000 miles on it so I have a few more to go /:>)

That's an astounding number of miles. About 28.5K miles per year for 34 years. Kind of hard to believe that kind of pace can be kept up. At some point, the bike would have to be down for serious repairs, making the miles per year actually higher than that. Not to mention serious "repairs" on the person putting the miles on!! ;)
 
Back
Top