Aluminium coupling flange

Restoration forum Bmwbike.com
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Ben Friedl

Aluminium coupling flange

Post by Ben Friedl »

Hi Mark,

Could you please tell me how to remove the aluminium coupling flange on the carden shaft? There is a steel collar that sits in front of the flange as well, are they both pressed on?.

Many thanks
Ben
Mark Huggett

Re: Aluminium coupling flange

Post by Mark Huggett »

Hi Ben

The steel collar is not original, and must have originated from a previous repair. However, if it works and has been neatly manufactured, thats also good. The old flanges were steel forged. Later BMW produced the spare replacement flanges from forged duraluminium. The flange has a press interferance fit on the shaft. That means that the hole in the flange is actually slightly smaller than the diameter of the shaft itself. These parts can only be pressed apart using a hydraulic press. Upto 5 tons can be used to press these two parts apart while as only 1,5 to 2 tons is needed to press them together again. You need suitable mandrels for holding them in the press, but this is a job that any engineering workshop can do quite easily. Don't forget to use an anti seize grease or lubricant such as copperslip on the parts before pressing them together.

Best regards,

Mark
Mark Huggett GmbH
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