Classic Harley Wheel & Star Hub Rebuild


Description: It’s time now to turn my attention to the rear wheel bearings.

Author: Bigincher
Date: Mon Dec 27, 2010 5:41 am
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Category: Articles/Miscellaneous Info

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A few weeks ago, I set about putting my old Harley Panhead chopper back on the road in good running order, after having been neglected for decades. I repaired the stripped motor mount studs, rebuilt the Linkert carburetor and intake tract, cleaned the gas tanks, and have been having a blast riding this old bike, the same one I ‘grew up’ on, having purchased it as my first Harley back in 1974. It runs great! But I’ll go through everything on this bike (except the motor and transmission), to make sure it will be roadworthy for years to come.

It’s time now to turn my attention to the rear wheel bearings. I haven’t had the hub apart since the 1980’s, and when I had the rear wheel off the ground last week, I noticed a lot of slop in the wheel bearing, so I wanted to get in there and see what was going on.
Incidentally, I checked the date code on the rear tire, and determined it was manufactured in 1986, so that was probably the last time I had things apart; Heck, that was only 23 years ago. The tire is sound, with no cracks or defects, so I’ll run it.

One of the nice things about a chopper is that they are easy to work on; I had the bike on the jack and the rear wheel off in short order.

I took the brake drum off too, to inspect the brake shoes. They’re serviceable, but there’s no better time than now to refurbish the brakes, so why not? More on that later, but for now, let’s rebuild a star hub Harley wheel!

First thing to do is to gut it out. I keep the parts on one side separate from the parts on the other side of the wheel, If you end up re-using the bearing rollers, you do NOT want to mix them up! Here’s the wheel, hub gutted, parts separated. All the brake side parts in a pan on the left, and all the star side parts in a separate pan on the right.
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I always use gasoline to clean my parts, then blow them off with compressed air. I noticed lately that gas just isn’t what it used to be. When I pour it into the parts pan, it’s a nice clear liquid. But after a short while, the corn evaporates out of it, leaving an orange-ish looking stuff. Sure not like the old days! I like to clean up all the parts and have them laid out for assembly. Here’s everything ready to go for the brake side…….
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And everything cleaned up and ready to go for the star side………..
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With everything clean and dry, the first step in rebuilding the hub is to check the running fit of the rollers. This is known as a “plug fit”, and here’s how it’s done.

Wheel Bearing “Plug Fit”

Armed with a selection of oversized roller bearings, as well as a bag of standard .250″ roller bearings, I set about to perform the “plug fit” method of determining the correct sized rollers for the hub. The specified “running fit”, or desired looseness of the rollers is .0010″ to .0015″. Logic states that if an oversized roller of .0006″ plug fits (times 2, one roller on each side of the cage), then a standard roller falls in the lower end of the specs, but if a .0008″ oversized roller plug fits, a slightly oversized roller must be used. These are the two sizes I have to work with, so I set out to prove my theory.
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Sure enough, the +.0006″ rollers made the nice plug fit. A plug fit is achieved with the largest oversized roller that can be inserted and all the parts still move freely with no bind. (There is also no clearance for lubrication!) Here’s the star side bearing with the
+.0006 oversized rollers. It still turns freely.
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I then removed those rollers and put them back in the bag. Care and due caution must be used to never have more than one bag open at a time, as mixing different sized rollers would be a disaster! Then I tried the +.0008″ rollers. I could get a little over halfway around the cage before they wouldn’t go in. Obviously, these rollers are too large to even make the plug fit. This is actually a good sign.
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I flipped the wheel over so the brake side was up, and tried the +.0006 rollers. They went in, but a little bit tight on this side. Everything turned freely, but just not quite as freely as the other side. So I carefully put those back in the bag, and got the +.0008″ rollers back out. As you can see, the inner bearing race would not go in the cage. That’s actually a good sign.
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So I determined the actual plug fit was achieved with the +.0006 oversized
rollers. Now we got to do a little math. There’s kind of two formulas here to arrive at the same conclusion. I got out the grease board, and made notes. My formula is the simplified version, written in black. Since the rollers go all the way around the race in a circle, there’s a roller on each side. So the actual size of the roller is doubled to net the total bearing size. In this case, .0006 x 2 = .0012 + .250 (standard size) = .2512″. Now subtract the size of the rollers, .250, and that leaves a clearance of .0012″. Right on the lower end of the specified range of the ‘running fit’ of .0010″ to .0015″.

Okay, that’s the simple way. Then I did the math again using the formula ‘by the book’, to prove my method is correct. In this case, you work with a single bearing diameter for the plug fit, or .2506″. Then you subtract 1/2 the running fit dimension to determine the actual roller size that gives you the ‘running fit’. Since the desired running fit is .0010″
to .0015″, subtract half that (.0005″ to .00075″) from the plug fit bearing size. The results indicate the correct size roller to use would be in the range of .2501″ to .24985″. Are you still with me? Since a standard roller is .250″, and they obviously don’t make rollers that are .24985″, a standard roller will be correct for this application. Yes, I could use
+.0001″ oversized, but since standard rollers already fall near the smaller end of the range, that’s what I will use.

Here’s the math I used. The black writing is my simplified formula, and the orange writing is “by the book”, and proves my formula. Same math, different approach, same results.
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Wheel Hub Reassembly

Okay… here we go! I have previously determined that standard size .250″ rollers
are the correct rollers to use in this rebuild, as explained above. Since the old rollers showed some pitting and degradation, I will use all new bearing rollers.

Start with the wheel, the brake side facing out.
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All the parts should be greased up good first— I use the blue Marine grease, this is the stuff that’s good in the wheel bearings of boat trailers— it’s real sticky stuff, and resists washout by water.

The brake side is assembled first, and the first piece to go in is the roller retainer thrust washer. The lip goes in, and the thrust surface faces out. Sometimes it’s necessary to tap this in place; if so, I use a deep socket of just the right diameter to lightly tap on, setting it firmly in place on the shoulder inside the hub.
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Next is the roller bearing retainer and rollers, with the open side of the retainer facing out. I worked the grease into the retainer around the rollers, so that there are no voids.
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The roller bearing washer is next.
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Now the first of two lock rings goes in, this one locks the roller bearing bearing assembly in place. Snap ring pliers are a ‘must have’ tool for this.
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Here you see the inner lock ring in place. I double check it to insure it is fully seated in the groove by rotating it in the groove.
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The inner hub sleeve is now installed.
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Since the cork seal is next, I like to slip it over the surface of the inner sleeve and insert the sleeve with the cork already started on it, since the cork is a tight fit. Always use new cork seals.
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With the inner sleeve installed, and the cork seal fully seated, it’s time for the cork retaining washer. The flat side goes next to the cork, with the lip facing out.
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Then the outer lock ring. Again, I rotate it in its groove to ensure it is fully seated.
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The assembly is now complete on the brake side of the hub.
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Now flip the wheel over so the star side is facing up, and it will look like this.
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First part to go in is the roller retainer thrust washer………..
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…………followed by the roller retainer and rollers, fully greased up.
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Again, the open side of the retainer faces out; the ends of the rollers are visible. (Note: now is a good time to lay the paper gasket in place. It’s easier to do now before the next steps.)
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Now the first of two thrust washers in installed. Actually, it just kind of lays there, so it’s better to have the wheel laying flat for the remainder of the assembly. If the star hub has a grease zerk, align the ‘tit’ of the thrust washer with one of the screw holes for the cover. (I don’t think it matters, but I always align it opposite the valve stem.)
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The thrust bearing sleeve is next. The flat side goes down.
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Followed by the second thrust washer. Align the ‘tit’ with the first thrust washer.
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The shims are next; they are the means by which the end play is set. Add shims to decrease the end play, remove shims to increase it. The standard shims are .002″ thick, and generally there are 5 of them. Examine them for tears, wrinkles, of defects, and replace any that are bad. Only four came out of this hub, and I had one that was a little rolled on the edge, so I tossed it and added 2 new ones.
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Use a new paper washer for the thrust bearing housing, or ‘star cover’. It’s actually easier to put the gasket in place before any of the thrust bearing washers and sleeve, as it has to be worked around the ‘tits’ on the thrust washers if you wait until now…..
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Now put the thrust bearing housing in place, lining up the screw holes. DO NOT install the cork seal at this time, because it is so tight it will mask the readings for setting up the end play.
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Followed by the outer cover.
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Go ahead and start all the cover screws. I have a handy little tool I use to hold screws while I start them, I bought this years ago— it’s original design is for installing that little screw that holds the ignition points to the points base, but I use it on a lot things.

I leave off the lock washers for now, as usually the bearing housing and cover have to come off and back on a number of times while establishing the end play.
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Now the fun part..! I set up my dial indicator, using the magnetic base to hold it on the rim, and carefully positioning the head so the finger is square and perpendicular to the end of the thrust bearing sleeve. I set it so the finger is somewhere in the middle of it’s travel, then zero out the dial.
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Push the inner sleeve all the way to the brake side, and ‘zero’ the dial pointer. Then push the sleeve as far as you can towards the star side, and notice the reading. We’re looking for a number between .003″ and .005″ for the end play, or more correctly called the “lateral thrust tolerance”. When I first assembled the star side with 5 shims and tightened the cover, I could not detect any end play, probably from the excess grease on some of the parts. So I took it apart and removed 2 shims, thinking I would rather work my back up, after having initially ‘set’ the assembly with 5 shims.

Three shims wasn’t enough, so I tried 4, and that wasn’t enough, and so I finally ended up with 5 shims again, and I got this reading of .004″ for the end play. Perfect!
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With the end play set, now the outer cover of the bearing housing is removed, and the cork seal installed. ‘James’ makes the best corks and gaskets I have found.
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The cover will now go on for the final time, so I use new ‘outside star lock washers’ on the screws, and use a dab of blue threadlocker as an added measure.
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Now, there’s one more very important step before this rebuild is complete. The hub needs 1 to 2 ounces of grease pumped into before it’s ready to go back on the bike. This air-powered grease gun makes fast work of it.
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This is the perfect time to give the wheel a good cleaning and polishing, so that’s what I did for the next hour or two. Here’s the wheel, all back together, and ready to go back on the bike after one more wipe-down!
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