13mm master cylinder leaking

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The master cylinder in my 74 Commando is leaking. I have not yet identified where the leak is originating from. It was upgraded to the recommended 13mm I was told. I understand that there are various people that have done these modifications and so I assume the seals and other parts may vary a bit. So my question I guess is how do I determine where and what to buy? I have yet to disassemble it or any Norton master for that matter.
 
I got the brembo m/c and ss brake line from CNW .... quick easy improvement , while not stock Matt stands behind what he sells , no one has ever told me my Commando sucked because of the change on my handle bar ..... just sayin’
 
I've seen too many reports of failed original Commando M/Cs to ever consider a sleeved M/C. Do as Craig did or if you want a cheaper setup, go with Grimeca M/C and caliper w/ss line. Excellent stopper. Add a floating 12" rotor and you are right up there with any modern bike. This is most important: make certain the area of the caliper piston is ~27 times larger than the area of the M/C piston. You could have Moto GP spec brake parts, but if not sized correctly you will be very disappointed. Size matters! Forget the originals, they were woefully wrong sized.
 
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gmlaverda,
You will need to take a picture of the inner piston area as there are about 4 options out there.
There is the RGM kit, the Replacement M/C that RGM reworks and sells to suppliers, The new M/C sold by Andover and I believe madass140 does a kit for the original Lockheed M/C. If I missed anyone please pipe up. You need to figure that out first. Report back.
Cheers,
Thomas
 
$18 plus postage gets you an RGM seal kit for a MC sleeved with their process and install is quite easy.
The problem lies with not knowing whose/what was actually done. Ideally you want to fix what you have.
Easy and inexpensive. https://www.rgmnorton.co.uk/buy/13m...on-with-seals-used-in-our-reline-kit_2530.htm

Otherwise you need to get a new MC which comes sleeved at 13mm from Madass at $150
http://www.tritonmotorcycleparts.com/297620485/category/146825/online-store

or from Andover Norton.

cNw offers a nice Brembo MC, while not stock looking, there is an adaptor to fix your original switch housing to it. cNw is not
cheap but Matt's stuff is the best and he will stay with you until you are satisfied.

These options preserve the original look of a Norton

There are a number of more expensive MC, brake cylinder and rotor options to give you braking power of a modern motorcycle.
Some require a whole new electrical switch.

If all else fails, tie a rag around the leaky area so your paint job doesn't get trashed and ride on (keeping an eye on the fluid
level in the reservoir.
 
Frankly, my experience with a sleeved MC makes me say, "DON"T do it!" My sleeved MC failed while riding, going from "normal" brake to no brake from one stop to the next! I then bought the CNW MC with the adapter to use the standard Norton switchgear and it's great.
 
Frankly, my experience with a sleeved MC makes me say, "DON"T do it!" My sleeved MC failed while riding, going from "normal" brake to no brake from one stop to the next! I then bought the CNW MC with the adapter to use the standard Norton switchgear and it's great.

14 years on my RGM 13mm sleeved MC with absolutely no issues and no leakage.
 
Frankly, my experience with a sleeved MC makes me say, "DON"T do it!" My sleeved MC failed while riding, going from "normal" brake to no brake from one stop to the next! I then bought the CNW MC with the adapter to use the standard Norton switchgear and it's great.

Who sleeved it? There are kits out there for DIY.
 
Since the OP has not determined where the leak actually is, it may not even be due the sleeved MC. My OE MC tended to leak at the reservoir cap. Threading the cap to reservoir always feels a bit off, like a partial cross thread. Researching threads here gave indication there should be some kind of sealing washer (out of a kind of fiber paper) in the cap. Mine had none. I whittled one out of some nylon plastic and now things seem a lot better, no leaks and cap seems to thread on better.
 
I'm not aware of any kind of paper gasket inside the reservoir cap. The rubber bellows is supposed to seal it. But it is true that the OP needs to identify where the leak is coming from.

Old Britts did sleeving at one time. I was put off by the idea when I learned that the master cylinder was no longer user serviceable after sleeving. Which to me means that eventually you have to throw it away. Which according to some is the best idea anyway.
 
I'm not aware of any kind of paper gasket inside the reservoir cap. The rubber bellows is supposed to seal it. But it is true that the OP needs to identify where the leak is coming from.

Old Britts did sleeving at one time. I was put off by the idea when I learned that the master cylinder was no longer user serviceable after sleeving. Which to me means that eventually you have to throw it away. Which according to some is the best idea anyway.

Cap Sealing washer Discussed here:

https://www.accessnorton.com/NortonCommando/master-cyl-cap-leak-2010.6091/#post-69817
 
Who sleeved it? There are kits out there for DIY.

I don't remember now, it was 7-8 years ago but it was a common, well-known supplier of the sleeved MCs. The original sleeved cylinder (on the bike when I bought it) began leaking and when I removed it there were some markings on it that I searched and then found the supplier. I sent him an email, he confirmed it was one of his and gave me the address where to ship it for resleeving, which I did. The second time it failed (several years later) was when it went from normal brake to no brake between stops. There is no feeling quite like pulling the brake lever and having NOTHING happen! ;)

But we all do what we are comfortable doing; if other riders here are comfortable with the sleeved MC, that's great. But the experience made me totally gun-shy toward them.

I suppose it's no different than any of the "arguments" here - what oil to use, safety wire or loctite, what ignition system, Amals or single Mikunis, etc... Compared to brake reliability, though, those other items are pretty much insignificant from a "saving your A%$" standpoint! :)
 
Thanks for all of the info gentlemen. This is actually the second issue I have had with the front brake. On a ride a few months back I pulled in the front lever only to have it go completely to the grip. I had a little braking there, maybe 10%, but this happened all of a sudden not gradually. After carefully limping home I managed to bleed the front and regain the brake. I bled out one large air bubble at the time. So I am not sure if this is related or not. I will dig into it later this winter and report back.
 
no brakes is no go when I built my commando I did not have original switch gear or MC or anything so chose 13MM Magura M/C, braided stainless hose from Rocky Point, rebuilt caliper with SS pistons, new, drilled, disc from Fluid Six......brake works as good as the one on my Honda Shadow and that says a lot..
 
I don't remember now, it was 7-8 years ago but it was a common, well-known supplier of the sleeved MCs. The original sleeved cylinder (on the bike when I bought it) began leaking and when I removed it there were some markings on it that I searched and then found the supplier. I sent him an email, he confirmed it was one of his and gave me the address where to ship it for resleeving, which I did. The second time it failed (several years later) was when it went from normal brake to no brake between stops. There is no feeling quite like pulling the brake lever and having NOTHING happen! ;)

But we all do what we are comfortable doing; if other riders here are comfortable with the sleeved MC, that's great. But the experience made me totally gun-shy toward them.

I suppose it's no different than any of the "arguments" here - what oil to use, safety wire or loctite, what ignition system, Amals or single Mikunis, etc... Compared to brake reliability, though, those other items are pretty much insignificant from a "saving your A%$" standpoint! :)

Experiences such as you described would deter me from ever using a resleeved master cylinder.
 
My advise to those offering master cylinder resleeving service: DON’T! The potential for a liability suit 100,000 times what you will ever make resleeving M/Cs should be evident.
 
14 years on my RGM 13mm sleeved MC with absolutely no issues and no leakage.
I have absolutely no issues with the RGM kit which I installed on my Interstate when I bought it. 450000 + miles later and still on original seals. I change the fluid every year and I keep an eye on the level in the reservoir. Two finger braking with the stock disk and caliper. If you like the period Stock look then this is still a good option.
Cheers,
Thomas
 
I was put off by the idea when I learned that the master cylinder was no longer user serviceable after sleeving. Which to me means that eventually you have to throw it away. Which according to some is the best idea anyway.
I don't know where you got that info from ?
Unless you mean that the original 5/8 bore system will no longer work. The sleeve is installed with an Allen Key. If the sleeve ever gets damaged, you use the Allen key to undo it and install a new kit.
T
 
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