1954 R25/3 Rear Plunger Removal.

[dieselyoda]

I need to pull the final drive on a 1954 R25/3. I'm stuck at the plunger cap on the rear shock.

With just about every socket that I own, even up to 5", I can't find a socket that fits.

What do I need to take this apart?

 

[20774]

Have you measured across the flats of the head to figure out what the size is?

I've never had the pleasure!! How's your German...here's a vintage workshop manual:

https://vintagebmw.org/library_data/R25-3_workshop_german_1952.pdf

And found this on the Vintage forum:

Removing the rear plungers on a r25/3

Remove top shock cover cap #15 https://www.bmwclassicmotorcycles.com/parts/all-parts/rear-axle-r25-r253/ Remove 2 pinch bolts #13 and #14 https://www.bmwclassic

vintagebmw.org

 

[dieselyoda]

As you know, Calipers/Micrometers can be a bit too accurate as they don't account for the next size face.
I tried every metric/imperial socket I own with no luck to get the fit I want.
Thinking my next best option is cut an old inter-tube and and fit a socket on that.
Not thinking a Framer's wrench is a good idea.

 

[kinterridge]

As you know, Calipers/Micrometers can be a bit too accurate as they don't account for the next size face.
I tried every metric/imperial socket I own with no luck to get the fit I want.
Thinking my next best option is cut an old inter-tube and and fit a socket on that.
Not thinking a Framer's wrench is a good idea.

I think, maybe it was 32mm, if not maybe 31mm or 33mm. And that is for a replacement, can't remember for sure if the OEM was the same, it's been so long ago.

 

[20774]

I think, maybe it was 32mm, if not maybe 31mm or 33mm. And that is for a replacement, can't remember for sure if the OEM was the same, it's been so long ago.

Picture?

 

[kinterridge]

I do not have any images, I've found an OEM part number 30 54 116 which I thought I cold find a spec on but nothing. I looked at MAXBMW thinking they might have a spec on it which they sometimes do and they have an image of the cap nut along side a MM rule, hard to pin point, but definitely in the 30's mm range. It is a different part number then I had found. The parts guys at MAX would probably measure it if they had one in stock. Hope this helps.

 

[20774]

I have a '52 R25/2 so I was hoping a picture would help to see if yours was OEM. Plus I can measure mine when I get a chance.

Here's another parts site with an image of the part #33533054116:

Search results for: '33533054116'

Default Description

bmwclassicmotorcycles.com

 

[69ZEFF65]

I had to mess with an R 25/3 a while back and ended up using a large crescent wrench with terry cloth padding to loosen the large aluminum nuts / caps that I think your talking about. Stuck it on nice an snug and gave the end of the crescent wrench a swift hit with the palm of my hand. After the fireworks stopped and I could move my hand again I tapped the end of the crescent wrench with a metal hammer. Caps came loose with no visible marks. I think good repops are available if you have to get serious.

 

[kinterridge]

Kurt, does your /2 have the round/dome non-hex caps? Vech had a tool with set screws for that style if I recall. I think the /3 was all hex, but who knows with crossover years and parts.

 

[20774]

My '69 R69S has the domed round caps with two holes in the sides 180 degrees apart. Not sure if the /2 you're referring to. The older plunger R25/2 has the hex cap nuts. Sounds like the OP has the hex nuts. I don't know when the round ones came in...maybe they were on the twins?

 

[dieselyoda]

Either I have Oldzheimers or I can't forget that beautiful, smart, witty and adventurous redhead I tried accidentally on purpose running her over with my truck. All well except for my self-esteem.
Really felt a good burn when she told me I have the reactions of an old bull and pretty sure my blue pills are as old as the bible itself.
No worries, got a date next Friday to cruise around watching people put their winter tires on.

Sorry for the sidebar, I needed to get some bragging rights in.

The nuts on the plunger are 32mm, double square or 8 points if you prefer that description.

I couldn't not find a double square in the size so I used rubber electrical tape and an 18" farmers wrench.

Sometimes referred to as a Filipino impact gun.

Two take aways, keep the rear axle in.

Make sure bike is damn well good and anchored. Be prepared, somebody might have gotten a bit enthusiastic with red Loctite.

 

[kinterridge]

Either I have Oldzheimers or I can't forget that beautiful, smart, witty and adventurous redhead I tried accidentally on purpose running her over with my truck. All well except for my self-esteem.
Really felt a good burn when she told me I have the reactions of an old bull and pretty sure my blue pills are as old as the bible itself.
No worries, got a date next Friday to cruise around watching people put their winter tires on.

Sorry for the sidebar, I needed to get some bragging rights in.

The nuts on the plunger are 32mm, double square or 8 points if you prefer that description.

I couldn't not find a double square in the size so I used rubber electrical tape and an 18" farmers wrench.

Sometimes referred to as a Filipino impact gun.

Two take aways, keep the rear axle in.

Make sure bike is damn well good and anchored. Be prepared, somebody might have gotten a bit enthusiastic with red Loctite.

Thanks for the follow up.