MASTER CYLINDER UPGRADE (2011)

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northur

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Jan 29, 2011
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I have been searching for any comments on the 13mm resleeving of the master cylinder so ithought I would post it. Had my front master cylinder drilled out and resleeved to13mm and added a braided line to replace the original one. I rebuilt the caliper ,but left it stock. The results were amazing ,brake comes on sooner you have more feel and vastly improves braking distance. I would recommend this cheap upgrade ,less than $300, for anyone that is satisfied just touring around.
 
northur said:
I have been searching for any comments on the 13mm resleeving of the master cylinder so ithought I would post it. Had my front master cylinder drilled out and resleeved to13mm and added a braided line to replace the original one. I rebuilt the caliper ,but left it stock. The results were amazing ,brake comes on sooner you have more feel and vastly improves braking distance. I would recommend this cheap upgrade ,less than $300, for anyone that is satisfied just touring around.
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Who did you have do the resleeve?
 
RGM in the UK do it for about US$ 120. I have had three done by them and I am satisfied with the results and their service. They do tend to wait until they have a batch of at least 10 and then do them all at once, so if you need it done in a week it's probably not your best option. Two of my bikes are on the cover of their recent catalogue, but I don't have any commercial relationship with them other than purchasing parts from them - actually I am probably sending their grandchildren through college, but that is unwittingly.
 
I was a little disturbed when Old Britts told me that they could resleeve the master cylinder but then it would not be owner servicable. Granted it will probably out live me without rebuild, but it still bothered me to think I couldn't rebuild it myself. Anybody know if this is the typical case for a resleeved master?

Russ
 
rvich said:
I was a little disturbed when Old Britts told me that they could resleeve the master cylinder but then it would not be owner servicable. Granted it will probably out live me without rebuild, but it still bothered me to think I couldn't rebuild it myself. Anybody know if this is the typical case for a resleeved master?

Russ
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Seems to be.
 
I've had a 13mm sleeved master cylinder for years and loved it. Then I hit some diesel fuel and scraped up the right side and had to replace the brake handle. Unknown to me the blade was a little out of specification and brake fluid return wasn't fully opening. I had a hell of a time bleeding brakes, then while riding the brakes started locking up due to fluid heating up and unable to return to brake resivoir efficiently. Finally after going through a quart of brake fluid and warping two rotors the out of spec blade became apparent! Just FYI! :cry:
 
Mine was resleeved just before I bought the bike & it is much better then any I had in the past. What did you do about the handle? I really would like to install a "dog leg" handle because my small hands & short little fingers. I'm hesatant to mess with it cuz it's such a pain to bleed but does anyone know of a "dog legged" handle that will work with the resleeved MC ???
 
bmwbob said:
I've had a 13mm sleeved master cylinder for years and loved it. Then I hit some diesel fuel and scraped up the right side and had to replace the brake handle. Unknown to me the blade was a little out of specification and brake fluid return wasn't fully opening. I had a hell of a time bleeding brakes, then while riding the brakes started locking up due to fluid heating up and unable to return to brake resivoir efficiently. Finally after going through a quart of brake fluid and warping two rotors the out of spec blade became apparent! Just FYI! :cry:
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Was your out of spec handle keeping the piston slightly depressed when it was fully released? Just want to know what we are looking for here.
Thanks
Russ
 
In the instructions that came with my resleeved MC it warns of different levers. I think there may be only two variations. I think this is a known problem.
 
1. If the m/c piston plunger spacer is too long, &/or, the lever tab is too thick to let piston retract far enough as brake fluid heats by use or sitting in sun pads can become locked to rotor. Fix is take a few 1000'th off plunger spacer or lever tab till brake free up and stays ok no matter the temps. A wet rag on over heated m/c and rotor can release to move again till corrected. Don't want much off or loose some pumping volume.

2. RGM and maybe others 'racing' levers have a crook shape for better closer grip as well as a bit better pivot point.

3. Best bike brake I've ever experienced was Ms Peel's 12 mm m/c, SS hose and RGM lever on drilled cast iron rotor. Best because it acted as ABS over 70 and matched my terror grip for crisis pull downs by not being so easy to lock up as moderns but just as capable to lock up so often had to back off grip in crisis.

4. Next best brake is on Combat Trixie, with just tiny rubber restrictor hole opened up till non functional to restrict fluid.

5. Old hoses can swell inside and act like the factory restrictor hole or worse.
 
When I began the deconstruction of my Mk3 two years ago, I found that the MC had been converted by Al Miles (I sent him a photo of the parts and he confirmed that the parts were his). He also confirmed that, while he serviced his conversions, he did not provide parts to allow for owner-servicing, like Russ reported regarding Old Britts. The parts were very well made and in mint condition, so, with some phone help from Al, I reassembled the MC; it has worked flawlessly since. The builders of these conversions are understandably cautious about inexperienced owners like me rebuilding or modifying their products.
 
Not wishing to appear too cynical but I suspect the makers of these kits are somewhat more wary of us owners buying the $25 overhaul kit from Kawasaki (on which they are probably based) and doing it ourselves rather than sending the unit back for a $300 overhaul!
 
Had my 73 Commando resleaved and added braided brake lines when I restored it 2 years ago. I sent the master cylinder to Stan Smith (Rocky Point) for the resleave job. The brakes were very much improved. Highly recommended. I recently purchased a '78 T140 Bonneville with an older restoration and original (unsleaved) brakes. The Commando brakes are far superior to the Triumph even with the Triumph's rear disc.
 
dave M said:
Not wishing to appear too cynical but I suspect the makers of these kits are somewhat more wary of us owners buying the $25 overhaul kit from Kawasaki (on which they are probably based) and doing it ourselves rather than sending the unit back for a $300 overhaul!
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I'd suggest you speak to some of the suppliers before making that assumption.
 
Hopefully you can read this. Take note of the first paragraph about the levers.

MASTER CYLINDER UPGRADE (2011)
 
Swooshdave, Everybody's kit must be based on parts that are commonly available, It's neither feasible nor affordable that anyone would commission master cylinder lip seals and dust covers for the limited numbers that they would sell to classic owners, especially since this is a standard size on many other motorcycle M/cylinders, the kits may have custom made pistons or modified standard ones. I have no problem with this myself or with the money charged for providing this service and I am completely satisfied with the 3 RGM units that I have bought. I would however be happy to subsequently replace the seals as necessary myself if I could source them locally.
 
dave M said:
Swooshdave, Everybody's kit must be based on parts that are commonly available, It's neither feasible nor affordable that anyone would commission master cylinder lip seals and dust covers for the limited numbers that they would sell to classic owners, especially since this is a standard size on many other motorcycle M/cylinders, the kits may have custom made pistons or modified standard ones. I have no problem with this myself or with the money charged for providing this service and I am completely satisfied with the 3 RGM units that I have bought. I would however be happy to subsequently replace the seals as necessary myself if I could source them locally.
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The reason I said that is because I spoke to the vendor of my kit and he said that although it could be rebuilt that he, in the many years, had not had a reason to. Master cylinders, especially for most lightly ridden bikes, shouldn't need constant rebuilding. The quality of the bore and other components will most likely far exceed the OEM parts. A well built piece with well maintained fluid could easily last 10 or 20 years.
 
As long as the piston is not allowed to rust by fluid changes or being made of SS steel not much to corrode or wear out. Still I'd want a way to renew mine now and then, or the folks after me.
 
Could it be they are worried about some sort of liability issue if they modify a stock part and then someone else does work on it and.............. you know what I'm getting at. Brakes are kinda important ya know? Dave that's the same guy that did mine 5 years ago, Still going strong.
 
Swooshdave, I agree with what you have said, I also doubt that one would have occasion to rebuild a master cyclinder for a number of years, but my response was to the post by Russ, commenting that he didn't appreciate that the kit he was referring to wasn't owner-serviceable. 20 years down the line the people who did the modification may not be in business any more, however if owners are aware that the internal parts from another machine will probably fit they at least have the chance to keep the bike on the road. I repair classic cars for a living and, as Hobot has said, often an ancient master cylinder can be repaired with a good cleaning, perhaps a light hone and new seals and dust covers. I have a friendly local parts shop who will measure seals or pistons and try to match them up for me, I always chuckle when I find a Daihatsu part that fits a classic Ferrari or something equaly exotic.

Hopefully when we are gone the bikes will still be serviceable and giving the next generation as much fun as we have had so far.
 
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