Swing Arm to Final Drive Nuts Removal

[88bmwjeff]

I've never been able to find a thin walled socket to remove the nuts that hold on the final drive to the swing arm. The bike is a 1988 R100 RT. Any suggestions.

 

[20774]

12-point nuts? Do you have the stock toolkit? Typically the 12mm (or could be 10mm) will fit that nut. I don't know what the torque is but I'm thinking it's in the 30 ft-lb range??

Some discussion here:

https://forums.bmwmoa.org/showthread.php?48249-Adventures-in-fasteners-Mono-shock-final-drive-nuts

 

[88bmwjeff]

Thanks Kurt. The space between the nut and driveshaft tube is rather narrow that my standard 12-point socket will not fit, nor will any of my box wrenches (that includes what came in the tool kit). The bike is a 1988 R100 RT. I was hoping someone has a tool they use and they can let me know what it is, so I can get one.

 

[20774]

So what is the size of the nut...mm across the flats? Can you get a socket and find someone to grind off some of the outside?

 

[83014]

Take the socket appropriate for that nut, put it on a short extension, place it in your drill. If handheld, use a bench vise to hold a file and grind the socket against the file until it fits the opening. If using a drill press, hold the file against the socket. I did this years ago to service my airhead swing arm.

 

[88bmwjeff]

Take the socket appropriate for that nut, put it on a short extension, place it in your drill. If handheld, use a bench vise to hold a file and grind the socket against the file until it fits the opening. If using a drill press, hold the file against the socket. I did this years ago to service my airhead swing arm.

This is what I'm trying to avoid. Not everyone seems to have this issue, so I was hoping someone would indicated what they use. If I have to go this route, I will.

 

[20774]

It would be nice to hear from Anton with suggestions. He has to do this often in his shop and maybe he has a source or two for a new tool.

 

[PGlaves]

I am curious what the nuts look like. I don't currently have an Airhead but when I did I removed these nuts with a normal (10mm I think) 12 point box end wrench.

 

[PAS]

I am curious what the nuts look like. I don't currently have an Airhead but when I did I removed these nuts with a normal (10mm I think) 12 point box end wrench.

He is talking about the swing arm nut, not the drive shaft to gear box nuts.

 

[lkchris]

I am curious what the nuts look like. I don't currently have an Airhead but when I did I removed these nuts with a normal (10mm I think) 12 point box end wrench.

Me too. Wonder if something changed with the late model single-side versions, as on my earlier bikes it was never a problem.

 

[PGlaves]

Me too. Wonder if something changed with the late model single-side versions, as on my earlier bikes it was never a problem.

Realoem shows the same nuts starting with the /5. I wonder of the OP nuts are something different.

 

[88bmwjeff]

Me too. Wonder if something changed with the late model single-side versions, as on my earlier bikes it was never a problem.

I can understand people's confusion, since I've rarely heard people ask for clarification on these nuts. I've never owned a dual shock version--just the mono-shock version. The nuts appear to be a 12mm, 12-point nuts, but don't quote me on it. As you can see in the above picture, the 12-point box wrench that came in the took kit does not fit. The wall thickness of the wrench is too thick to fit between the nut and the driveshaft tube. I may just have to make my own tool, but I was hoping not to go down that path.

 

[PGlaves]

View attachment 84952

I can understand people's confusion, since I've rarely heard people ask for clarification on these nuts. I've never owned a dual shock version--just the mono-shock version. The nuts appear to be a 12mm, 12-point nuts, but don't quote me on it. As you can see in the above picture, the 12-point box wrench that came in the took kit does not fit. The wall thickness of the wrench is too thick to fit between the nut and the driveshaft tube. I may just have to make my own tool, but I was hoping not to go down that path.

The OD of the head of that wrench is larger than a typical box end wrench I think.

 

[PAS]

My mistake, thought it was the swing arm nuts. Amazing how words can get in the way of reason.

 

[20774]

I've typically found that the stock took kit box end wrench was "thinner" than normal box end wrenches. They have to save weight somehow, don't they?

FWIW, my /7 has 6-sided nuts. I don't have metric deep well sockets but was able to easily fit a 9/16" Craftsman deep well socket around the 12mm nut. I checked...the nuts are 14mm and I could easily get a socket on it. Different animal and configuration, I know...

 

[nrpetersen]

That's why every shop needs a metal lathe. I don't know how you run a household without one. It was a little hard to convince my wife though..............!

A grinder/file can make quick work of a box end wrench. There's nothing sacred about even Snap-on stuff.

 

[Anyname]

Take the socket appropriate for that nut, put it on a short extension, place it in your drill. If handheld, use a bench vise to hold a file and grind the socket against the file until it fits the opening. If using a drill press, hold the file against the socket. I did this years ago to service my airhead swing arm.

I'd suspect that a file might not work on a hardened socket. I have ground down hardened items by spinning the work piece with a drill press as suggested but I used a Dremel tool with an abrasive tool clamped in a block to do the cutting.