Mark III Front Master Cylinder

Greetings, everyone...the ongoing saga of my Commando rebuild has hit a roadblock, and I am hoping someone can send me inthe right direction. I had previously purchased Sparxs Mark III ('75) handlebar switchgear for MarkIIA ("74) Commando as an upgrade to the old stock pieces. I didn't realise that the master cylinder for the MarkIII is a separate item that screws in to the back of the right hand switchgear assembly. On the MarkIIA, it is all one piece. Soooo, now I need to find a master cylinder for a Mark III. Nothing on ebay, and nothing from a few used parts suppliers I have contacted. Anyone know where I can find one?
Thanks in advance for your help..

Mk III front brake master cylinders are a one-year-only-item; so they're scarce as hen's teeth. You should consider replacing it with a used, but suitable, Japanese unit.

Using a Japanese mastercylinder will not allow you to use the new Mk3 switchgear. If you want to use the Mk3 switches you will need the Mk3 mastercylinder. If you are willing to go to Japanese, Italian, or aftermarket switches, then the Japanese mastercylinder will work and give better braking if you find a 12 or 13 mm unit.

I would suggest talking to a dealer who does the Al Miles sleeve conversion on an exchange basis and see if they won't work a deal to take your mastercylinder as a core when you purchase a newly 13mm sleeved Mk3. You might have to come up with a little extra coin, but you will wind up with a master cylinder that will bolt up to your switches and stop better to boot!

If you don't like that idea, PM me and I'll dig into my stash and see if I have a decent Mk3 master. It will probably need to be rebuilt though.

Try Phil Radford, Fair Spares in San Jose Ca.
408-292-6563

Ken G.

I have an 11mm Nissin MC that I used to replace the MC, switchgear assy with. It needs a 10mm (if I recall correctly) banjo-bolt/inline brake light switch and you have to alter the stock lever (painful to cut up a pricey stock part). It's very compact, but dull gray and ugly. Great brake feel though.

I'll head to the garage and see if I can can get a part number.

Cheesehead Commando said:

Soooo, now I need to find a master cylinder for a Mark III. Nothing on ebay, and nothing from a few used parts suppliers I have contacted. Anyone know where I can find one?

Click to expand...

All the parts to build the MkIII master cylinder should be available from your Norton parts supplier?

The piston assembly is the same as the earlier type, but you would also require the MkIII brake lever, reservoir diaphragm and reservoir cap, as they are different parts to the earlier unit.



http://www.nortonmotors.de/ANIL/Norton% ... &Plate=025


The MkIII throttle assembly is also incorporated into the MkIII switchgear.


http://www.nortonmotors.de/ANIL/Norton% ... &Plate=024

Keith,
You have a PM.
Ron L