In page 02 BMW R75/5 General Tear Down, I show to remove the swing arm from the transmission and the rear drive from the swing arm. This is what I started from.
This page covers removal and replacement of the swing arm bearings and races and the powder coating of the swing arm.
|31 41 2 000 331||Swing arm dust seal, Qty (2)|
|07 11 9 985 005||Swing arm bearing, Qty (2)|
Here’s a picture of the tool; “some assembly is required”. This is explained in the included instructions, and I’ll show you how it goes together.
I found the design of this tool very clever; combining common hardware with a clear understanding of how materials behave under stress. Very slick.
Assembling The Cycle Works Swing Arm Bearing Puller
First, put the plated nylon lock nut on the plated 16 mm bolt until the threads are just past the top of the lock nut with the bolt and thread faces aligned. In a moment, it’s clear why aligning the faces matters.
Next, screw four of the long socket head bolts into the plate with the six threaded holes leaving two adjacent holes open.
Screw the bolts into the plate until they are even with the bottom of the plate.
Now, place the 16mm bolt with locknut inside the four socket head screws. Ah … that’s why the bolt and nut faces need to be aligned 🙂
Next, put some wheel bearing grease on the top of the 16 mm bolt head. Finally, screw the other two socket head screws into the plate so the 16 mm bolt is surrounded. Then, place the head of the socket screws on the work bench, adjusting them in their holes so all the heads sit flat on the top of the bench.
The long threaded rod has a taper on one end and a hole for an Allen head wrench on the other. Put a little wheel bearing grease on the tapered end. Using an Allen wrench, screw the threaded rod into the center hole of the plate until it touches the bottom of the 16 mm bolt.
At this point, the tool is assembled, so its time to use it. As shown here, the dust seal has a metal sleeve in the middle.
Use a screw driver to the pop the sleeve out of the dust seal. It comes out very easily.
Insert the Allen wrench into the threaded rod. Then, place the heads of the six socket head screws on top of the rubber part of the dust seal and push down hard enough to deflect the rubber seal and tighten the center threaded rod. This pushes the 16 mm bolt head under the heads of the six Allen head bolts spreading them outward under the edge of the dust seal. Keep tightening the center threaded rod until you see all six Allen bolt heads are lodged under the lip of the dust seal as shown below.
Now, put the metal cylinder over the threaded plate so it is centered on top of the swing arm and not touching the edge of the dust seal. Then put the steel plate and the washer on the center rod and thread the 17 mm nut finger tight down on the washer. Check to be sure the metal cylinder is still centered on the outside of the swing arm and is not touching the edge of the dust seal.
Use a box end 17 mm wrench to tighten the nut pulling the threaded rod and the dust seal out of the swing arm. If the puller pops out of the seal, you didn’t tighten the threaded rod tight enough to spread the six Allen head bolts far enough under the lip of the dust seal. Back off the threaded rod, reinsert the Allen head bolts and tighten the threaded rod a bit tighter and have another go.
And here you see the dust seal has been removed an is captured by the heads of the six socket head screws surrounding the 16 mm hex bolt head.
When I tightened the center threaded rod, I over tightened it so the 16 mm bolt head extended too far and got trapped by the socket head screws. When I unscrewed the center rod, the 16 mm bolt wasn’t able to come loose and I couldn’t get the dust seal off the six bolts. So, put the aluminum plate, washer and nut back on and keep tightening the center threaded rod until you hear a “pop” which is the head of the 16 mm bolt going past the socket head screws.
Now, you can remove the dust seal from the six Allen bolts. You can unscrew two of the socket head screws to free the 16 mm bolt and slide it back inside the Allen head bolts. Then screw the two Allen head bolts back into the plate being sure all six bolt heads are level.
To remove the bearing, just stick your finger in the center and pull it out. If you are a gentleman of refinement, you can use your pinkie finger to extract the bearing from the race. 🙂
The bearing race is removed using the same technique: set the heads of the six socket head screws under the edge of the race and tighten the threaded rod until they spread out under the edge under the race.
Again, put the cylinder, metal block, washer and nut onto the threaded rod and use the 17 mm wrench to pull out the race.
On the shock side of the swing arm, there is a metal cap under the race to keep grease from filling up the hollow center section of the swing arm. Mine was stuck to the bottom of the race hardened grease. Fish it out if it doesn’t come out with the race.
The vertical lines you see on the inside of the race in the picture below are due to Brinelling.
This is caused by the tapered roller bearings pounding against the race and deforming it. The rollers never fully rotate as the swing arm only moves up and down, but doesn’t rotate in a full circle. Eventually, the rollers indent the face of the race. I expected this due to the age and mileage of these bearings.
Flip the swing arm over and repeat the process on the drive shaft side. There is no grease cover under the bearing race as the tube surrounding the drive shaft blocks any grease from entering the hollow center of the swing arm.
Powder Coating the Swing Arm
I don’t want to remove the drive shaft under the philosophy of “let sleeping dogs lie”, but I am going to have the swing arm powder coated. I want to prevent any direct hits to the universal joint and it’s bearings during bead blasting, Here’s my solution: a custom fabricated Progresso “sock can” over the universal joint. This took me several hours to fabricate, but it was well worth the time.
If you want a “soup can sock” of your own, send me an Email with your mailing address and I’ll let you know how much it will be with shipping, handling, and if you live in Colorado, sales tax.
I added a warning note about protecting the surface on the other end of the drive shaft tube where the rear drive mounts to the swing arm.
Installing the New Races and Bearings
Here’s the picture of the swing arm after powder coating. The soup can sock seemed to keep the universal joint from being bead blasted.
I washed the swing arm thoroughly to remove any residual debris from the bead blasting.
I cleaned up the powder coat over spray from the arms that hold the bearings. One arm was fully coated inside and the other had minor over spray. That’s my fault as I should have put a masking tape note over them as I did on the rear drive gasket surface. No worries. It’s easy enough to remove the powder coating.
I use a sanding drum on a Dremel tool and then follow up with 600 grit paper so the inside surface is smooth and shiny. It is easier to drive the race in when the inside of the arm is smooth and clean.
The shock side of the swing arm has a cover plate that retains grease but the drive shaft side does not. Here are the new parts in order of assembly, top to bottom, inside to outside, with the drive shaft side parts on the left and the shock side on the right.
I started on the drive shaft side. I put the races in the freezer for an hour to shrink them. I put some engine oil on the outside of the race and use the Cycle Works aluminum block to drive the race into the opening keeping it parallel with the sides of the hole. The race wants to rock side-to-side when it starts, and I found tapping the sides of the race, going around the circumference with a soft mallet, helped seat it squarely in the hole before driving it in.
Using the flat side of the aluminum block and a hammer, drive the race into the arm until it’s flush with the top of the arm.
Then, using the shorter side of the aluminum block, drive the race all the way into the arm until you hear it ringing indicating it is seated.
This is the shock side arm cleaned and sanded with 600 grit wet paper.
The cover plate is indented and goes into the bottom of the tube and the race sits on top of the plate on the raised edge.
The cover slides in easily so you don’t have to drive it in.
Just as you did on the drive shaft side race, use the flat side of the aluminum block to drive the race flush with the top of the arm and then use the short edge to drive the race deeper until it bottoms out on the top of the grease cover.
I use NLG2 EP (Extreme Pressure) red grease and hand packed it into the bearings. I didn’t use my pinkie this time, but did wear my formal black gloves when I inserted the bearing into the race.
Next up, install the dust covers and sleeves. The swing arm pivot pin slides through the sleeve and then inside the bearing. I’ll cover installing the swing arm pivot pin when I write up installing the swing arm in the frame.
The sleeve goes under the rubber seal of the dust seal with the wider flat, or hat, of the sleeve against the face of the bearing. You can insert the sleeve after the dust seal is installed and it will look like this.
Use the flat side of the aluminum block and a gentle tap with a hammer to drive the dust seal in until it is flush with the top of the arm.
Then, push the sleeve through the rubber seal in the dust cap so it’s centered in the dust seal and the hat is completely under the rubber seal.
All done. After powder coating and new bearings, the swing arm is ready to install in the frame.