I’m going to powder coat the swing arm, and the bike has 83,000+ miles on it, so I am removing the swing arm bearings and plan to replace them.

Airhead Swing Arm Bearing Changes

BMW used two different style bearings on the airhead swing arm: an unsealed 30203 bearing that was changed part way through the 1981 model year (01/1981) to a sealed bearing, FAG 540619. Changes in the swing arm bearing assemble were made at the start of the 1981 model year (09/1980) when the pivot pin was shortened and the dust cap changed to accommodate the 30203 bearing with the shorter pivot pin. Then in January 1981, the sealed bearing was added with it’s included dust cap.

Looking at the MAX fiche, you will see three lines showing compatible components for  the swing arm bearings.

The top line shows the components used on the 1970-1980 swing arms.

• Item (8) is the 30203 swing arm bearing,[part# 07 11 9 985 005]
• Item (7) is the “top hat” that fits in the dust seal [part# 36 31 4 038 142]
• Item (5) is the dust seal.[part# 31 41 1 233 252]
• Item (3) is the swing arm pivot pin, [part# 33 17 1 230 301]

The pivot pin is 48 mm long and the 30203 bearing is 40x17x14 mm.

Starting in model year 1981 (09/1980) the parts in the second line were used for one year only. The swing arm pivot pin was shortened, the dust cap changed to accommodate the shorter pin and the top hat eliminated for a washer.

• Item (8) is the 30203 swing arm bearing,[part# 07 11 9 985 005]
• Item (6) is the washer [part# 33 17 1 236 956]
• Item (5) is the dust seal.[part# 33 17 1 236 897]
• Item (4) is the swing arm pivot pin, [part# 33 17 1 236 955]

The pivot pin was shortened to 42.5 mm to stiffen it with the 30203 bearing.

Starting in the 1982 model year (09/1981) the bearing was changed to a sealed bearing, and the washer and dust seal were eliminated.

• Item (8) is the sealed swing arm bearing, FAG 540619, [part# 33 17 1 241 546]
• Item (4) is the swing arm pivot pin, [part# 33 17 1 236 955]

The sealed bearing has a sleeve that replaces the top hat. So the bearing dimensions changed to 40x17x17 mm.

The Problem With Roller Bearings In a Swing Arm

Roller bearings are not a good choice for the swing arm. They rely on the inner rollers revolving inside the outer race to keep grease between the face of the roller and the race. But the swing arm never moves enough to make the tapered rollers move a complete revolution, let alone lots of revolutions as it would when these bearings are used for the wheel bearings. Consequently, the grease gets pushed out between the roller bearing and the outer race over time resulting in metal-to-metal contact. This lets the roller hammer the outer race. That deforms the outer race and hardens the part of the outer race in contact with the roller resulting in what is called brinneling of the race. This makes the bearing notchy so the swing arm isn’t moving smoothly moving up and down which in severe cases can noticeably affect handling. I expect the sealed bearing outer race to show damage when I remove it.

Tools

The change to the sealed bearing affects the tools needed to remove the inner race. For the 30203 bearing, your finger is perfect as you can lift the inner race out of the outer race. But, the sealed bearing is packaged as a unit with the inner and outer races connected to each other. You can’t lift the inner bearing race out of the outer race, you have to forcibly remove it with a blind bearing puller which destroys the bearing. Since the sealed roller bearing was designed not to need greasing for the life of the bearing, destroying it to remove it makes “sense” (I guess).

I have used the swing arm/wheel bearing puller from Cycle Works to extract the swing arm bearing outer race on bikes that use the 30203 bearing. But it’s too big to fit inside the sleeve of the inner race of the sealed bearing.

A German company, Kukko, makes very good quality blind bearing pullers for professional use, and they come with a corresponding price. So I looked around for a set of blind bearing pullers and found some for less than $60.00.

• 16 Piece Blind Bearing Puller with Slide Hammer

This kit has a slide hammer and a set of puller legs when more force–that will be required for the outer race extraction–is needed. There are various size expanding sleeves that cover a wide range of bearing diameters, so I bought it.

The BMW tool for this job includes a collar that fits around the tube the swing arm bearing sits in to provide a flat place for the feet of the puller to press against, and to keep the puller centered over the bearing. The collar and puller with legs is necessary for removing the outer race, but they are not needed to remove the inner race. A slide hammer will get it out. This kit doesn’t have a collar so I made one.

Blind Puller Collar Fabrication

I took measurements of the tube the swing arm bearing fits inside of. The outer diameter is 46 mm and the inner diameter matches the bearing race, 40 mm. The edge of the tube is 6 mm thick. What I need is a ring with a 41-45 mm hole and another ring with a 46 mm hole.

I headed to my local ACE hardware to wander around the aisles to see what I could find. I ended up getting a very large flat washer about 5 mm thick with a 41 mm hole. It has just enough clearance for the outer race to slide past it.

Then I found a conduit box nut, 1-1/2 inches, that has a 46 mm hole across the threads.

There is a raised edge on the lugs of the conduit box nut and I grind them flat with my Dremel tool. I use a dab of JB Weld on each tab to tack the nut to the flat side of the large washer and center it around the hole in the washer using a 2 mm Allan key to to keep the gap uniform.

When it dried, I test fit the collar on the swing arm tube. The hole in the washer was very close to being even around the bearing with a slight gap. I decided to even up the gap with a grinding stone in the Dremel tool. I likely enlarged the hole in the washer to about 42 mm and I visually confirmed the edge of the hole was on top of the edge of the tube and didn’t cover the edge of the bearing outer race. Then I added a bead of JB Weld all around the outer edge of the conduit nut to secure it to the washer.

For less than $5.00 I now have a stout collar for the blind bearing puller jaws to push against that I can use to extract the outer race.

Video

I made a short video showing how I used the blind bearing puller and slide hammer to extract the inner race. I show how to use the blind bearing puller with the collar, and the Cycle Works tool, to extract the outer bearing race. Either tool will do the job handily.

Remove The Inner Bearing Race

I used a screw driver to pry off the dust seal. The bearing is a FAG 540619.

I found the correct size expanding sleeve. When I tighten the screw, it expands the feet of the sleeve.

I tighten the expanding sleeve and then I attach the slide hammer and use it to pop the inner race out of the bearings with a couple hard pulls on the hammer.

Remove Outer Bearing Race with Blind Bearing Puller & Collar

I use a larger expanding sleeve that fits the outer race. I insert it inside the outer race and tighten up the screw to expand it. I put the collar on the tube and screw the expanding sleeve into the jack screw of the puller.  I adjust the puller jack screw to position the puller feet on top of the washer. The feet want to walk a bit, so some fiddling is required to get them directly across from each other and the same distance apart from the center of the outer race.

I use a box wrench and turn the nut. The puller has plenty of force and the outer race comes out of the tube without any drama.

Here is the sealed swing arm bearing after removal and it’s destruction.

From left to right, the outer race, inner race with sleeve and the dust cover. You can see in the picture above and the one below the brinneling of the inside of the outer race as there are strong vertical lines on the inside of the race. It’s time to replace the bearings.

Remove Outer Bearing Race with Cycle Works Bearing Puller

I show how to do this here:

• 33 BMW 1973 R75/5 Remove & Install New Swing Arm Bearings

As a recap, here is how the Cycle Works bearing puller goes together.

Clearly, either the Cycle Works or the blind bearing puller set I purchased can easily remove the outer race. Unfortunately the Cycle Works puller is not able to remove the inner race of the sealed bearing.

Condition of Outer Races

I inspected the outer races. There are regular bands of discoloration. This is called “Brinelling” and it is where the metal in the outer race has been pounded by the rollers creating valleys and hardening the race. These bearings were ready for replacement.

Revisions

2019-11-23  Edits and typos.
2020-03-18 Added “Condition of Outer Races” section.
2020-06-03 Change link for blind bearing puller to general search