Replacing Worn Out Pieces
It's easy to forget about wheelbearings. On the West Coast, we only have rain and mud about
three months out of the year (if that), and precision parts seem to last forever. Whatever the weather's like in your neck of the woods, sooner or later, you're going to have to replace a set.
It's not really as difficult as it sounds.
WHEN THEY NEED REPLACING
It's easy to tell when your bearings need attention-the symptoms are anything but subtle. If you spin one of your wheels and hear a whole lot of scary, crunching noises, you know the problem. The wheel probably won't spin freely either, and when you tighten the axle, chances are the wheel tightens up, too. Remove the axle nut and pull the axle out. If it doesn't pull out easily, you've certainly got a problem; this is a good time to check the axle and make sure it isn't bent. Bad bearings can bend an axle in no time and a bent axle can wreck a good set of bearings, so make sure you don't cause more problems than you cure.
IT ISN'T THAT HARD
So now you know they have to come out. Do yourself a favor, and don't just start beating on them with a hammer. Sit down for a few minutes with a shop manual or owner's manual, and find out what the bike manufacturer says is the right way to do it. On some hubs, the bearings are knocked out from each opposite side; on others, they all come out one side.
If you don't have a book for your bike, clean the hub off and take a long look at it. If there's a snap ring on one side, you can be sure that at least one of the bearings is going to come out of that side. Now, look at the other side. If a seal is blocking your view, carefully pry it out with a screwdriver, or tire iron. If the hub is formed around the outside of the bearing, it'll have to come out the other side. Otherwise, if it looks like smooth sailing, it
should come right out with a little tapping from the other end.
THE HEAVY STUFF
In order to remove them, you'll need a medium/heavy hammer and a soft steel drift pin. This is easy to say if you have a soft steel drift in your toolbox, but what if you don't? Not to worry, many things will do the job. A piece of steel rod smaller than the inner diameter of the bearing will work fine. If you don't have one handy, here's the hot setup: Scare up an old set of handlebars and cut the cross brace tube off. Straighten it out if it's tweaked. What you have now is a ten-or twelve-inch drift pin that'll come in handy for the rest of your life.
Pick the bearing you want to remove first. Slip the bar through the center of the opposite bearing so that the edge of the bar just touches the inner race of the bearing on the other side of the hub. Start tapping on the inner race, and keep moving the bar to a different position: up, down, left, right. You'll gradually push the bearing out the end of the hub. As the bearing moves out of the way, the spacer tube in the center of the hub will move around and make it easier to get a bite on the bearing with the drift pin.
Disregard all this if you have a set of bearing pullers. And, if you know how to use them, you
have no reason to read this except for the laughs it might produce. Ruined bearings will usually come out easier than good ones, but if they fall out, you may now own a ruined hub. Also, keep in mind that pounding on the inner race, although it's normally the only way to get a bearing out, can wreck them if you're not gentle. Light tapping, back and forth, will eventually coax the most stubborn
SAVE OR RE-USE
Now that you have a fistfull of greasy bearings, you can decide what has to be done. Clean all the old grease out with solvent, soak them in a little oil and check them out. Work the inner race back and forth and check for excessive play. A tiny amount of up and down (radial) play is okay, but any discernible amount of back and forth (axial) play is a vote for the scrap bin. Give them a good spin and listen for gritty noises; look for any sign of rust or pitting on the balls. Find one or the other and you throw them away.
Let's suppose you have to buy new bearings. You have
two ways to go:Either go down to your local dealer and pick up a set of stockers, or search out the nearest bearing supply house and possibly get something better.
More than likely, your dealer is going to give you a set that is exactly the same as the ones you have; that is, if the ones you pounded out of your hub were sealed on one side, the new ones will be sealed on one side, also. Single-sealed bearings are good if you like to repack your bearings periodically, and they are the cheaper alternative. But you may want to look for something better, and maybe save a little work somewhere down the line.
If you ride in a lot of mud and water and don't like to be pounding on your wheels every month, it is possible to buy a set of quality bearings with seals on both sides, although they're not cheap. Bearing supply houses used to be the perfect haven for the bucks-down enduro rider; you could pick up a full set of bearings for little more than what your dealer was asking for one. But at supply houses, you can buy American-made bearings (in any seal configuration you think you need), which are usually much better than stock.
Say you destroyed a set of wheel bearings on your bike from riding in deep mud. You don't want to put stock ones back in because you feel the need for something better and you want bearings that are fully sealed. No problem. Pound out your bearings, look at the little number stamped on the edge of the outer race or the outer seal, and it should say 6202.
Bearing numbers are nearly universal, and any house will know what a 6202 is. SKF makes excellent quality bearings, and they use the same numbering system we're talking about. Look in the phone book for the closest SKF dealer. Take your bearings with you, and if you want ones with a single seal, the number will be "6202 RS." If you want double-sealed bearings, the number is "62022RS."
This tactic will work with practically every motorcycle made, as they all use standard bearings. But every now and then, you'll come across an oddball. In this case, just take the bearing in with you, and any decent supply house will be able to match it up with something. Hint: This goes for all bearingsnot just the ones in your wheels.
BUTTON IT UP
Now you're back in the garage with a set of shiny, new bearings. If they have seals on only one side, or no seals at all, pack them full of a good grease, such as Bel-Ray MC
The best way to get them back into the hub is with a hydraulic press, but if you don't have one, the second best way is with a beating installing tool, and you surely don't have one of those.
The simplest way is to start them in with a plastic mallet, or by hand, and then tap them home using a properly sized socket to spread out the hammer blows. Remember now, we're talking about gentle tapping; anything harder than that and you'll screw up the bearing. Try to tap on the outer race only.
Once you have one side in and firmly seated, drop in the center spacer and line it up. If you want to be really trick, use the axle or a suitable piece of tubing to line up the seated bearing, the spacer tube and the next bearing in line. Seat the next bearing (and the next one, if your hub uses three or more), replace all seals and snap rings, and you're done.
Author：mosbearing 2008-7-23 Source: View(791) Comment(0)