13mm Master Cylinder Upgrade (Again)

Status
Not open for further replies.
Sometimes after OEM sleeve job or even non seleeved Lockheed a slight activation of lever or even just in sun a while, brake can lock up so still locked on lever release. If it does then may have to shorten the plunger the lever tab touches to allow enough piston return travel to expose the relief port. I had this happen after months of 13mm OEM success - about 60 miles leaving home for Ohio summer rally, stopped at a m/c builder to look around & get delayed seeing a boober Hog like Commando rendition with many interesting details to take in. Got on Peel to leave so rolled a couple feet to road edge and lightly pulled lever for instant lock up almost falling over. WTF!! Took a while to figure out the issue and solution, rub plunger on side walk a few times/few 1000'ths - till lever retracted piston sealing enough to let heated fluid expansion out of line back into reservoir. I've read others had this happen on first assembly to alert them but mine took most a hour in hi sun to happen, which implies could of happened on the fly if using brake more than air flow cooled it. Another task for hair dyer use on Commandos.

 
Last edited:
I made my own sleeve and JB welded it in. It will not shift.
Jaydee

Yeah, that's pretty much what the re-sleever said of mine when I had it done but he had to change his view from "it Can't shift" to "it SHOULDN'T have shifted.! ;) To be fair, it's been fine since it was re-sleeved the 2nd time though, to ALSO be fair, because of my switching Cylinders back/forth, it has maybe 35% of the actual braking duty since then.

Re JB Weld: I'm a big JB Weld fan and would think it would be Ok in that application if it isn't affected over time by brake fluid. I have seen posts/pics that it peeled away in areas exposed to brake fluid though JB WELD claims it is suitable for auto use as far as any auto fluids are concerned as long as the temperature of the JBWELD does not exceed whatever it's upper limit is - I seem to recall it's around 450F but I'm not sure. In any case, if a master cylinder gets to 450F, the bike is on fire anyway. :)
 
Full cured JBW can withstand about any fluid but heated acetone for a long time. JBW is not much an adhesive but to itself, only really holds by binding into surface texture and DOES NOT SET UP well till a few days or fairly hi heat to speed up reaction to use in 24 hr. I suspect JBW sleeve could come loose - if fluid filled before full set up could allow some seepage into polished surface but once set up would have to mill out sleeve or heat to like 600* F to soften to use a puller some how locked into sleeve.
 
I used Madass's sleeve, it's retained with green loctite but I added a 3mm of grub screw just in case, no evidence it's needed but it was easy to add. It's on the handlebar side so cannot be seen.
 
How many different outfits now offer the piston sleeve kit for Do-It-Yourselfers, and are they all pretty much the same?
 
OLd Britts offerred it, but I don't know if they do it themselves or what.
RGM offers a sleeve kit which entails boring and tapping the MC and fits a rubber pc at the bottom of the sleeve, which is already ported.
Don Pender's kit uses Loctite to hold the sleeve after it's pressed into the stock bore, then you use tiny drill bits to make ports in the sleeve, using the old ports for position.

So at least 2, maybe 3 or more, and No, they are not the same.
 
of course you could I've sold many of my TZ/TD 260mm 4LS brakes set up for Norton forks, they are all over the planet.
 
Posting up again on this, having learned a new factoid about the madass 1/2" sleeve kit.
If the outer piston end is more than 7mm from the end of the stock MC opening (for my MC anyway), the primary cup begins to encroach on the bypass or compensating port. Not all MC's will be exactly the same, I reckon, but this might provide a baseline.
I had to remove some material from the lever-stop area of the MC, to allow the lever to pivot farther out and get the piston back.
 

Attachments

  • 13mm Master Cylinder Upgrade (Again)
    MC_piston end.JPG
    104.8 KB · Views: 384
  • 13mm Master Cylinder Upgrade (Again)
    MC_leverstop.JPG
    100.1 KB · Views: 383
yep just like i did on side walk so glad turned out to be same simple length/travel issue. Some might of thought you just incompetent not getting first time bolt up success on supposed consistent hi end up grade kits.
 
I've read lots of threads on forums about this subject and while the Norton Purists won't like what I'm about to suggest it's a damn sight easier and probably safer than trying to adapt the original Lockheed master cylinder to 1/2" or 13mm..... Get yourself a second hand 1/2" master cylinder off another bike and fit it along with Ferodo pads and a braided hose. I got a quality 1/2" Nissin master cylinder off a Honda with the bonus of a nice adjustable span lever for £30. You need to fit the Lucas bar switch back on so I got a used clutch lever mount and with a bit of fettling and paint it does the job and looks good, the hole centres are the same on both sides. And if you ever need spares for the Nissin master cylinder they're readily available.
When you do the maths it's astonishing how much more line pressure a 1/2" master cylinder will produce over that of a 5/8" one for the same strength pull on the brake lever, around 40% I think. The only danger being running out of lever travel as discussed on previous contributions.
 
That’s one option. Or, if you’re a purist, an exact replica of the original unit, but with a 13mm pistons, is available.

Both options would be preferable to DIY re sleeving IMHO.
 
Status
Not open for further replies.
Back
Top