Hi all, I've seen various threads on this subject and I wanted to share my latest improvement: the fitting of a new Andover Norton 13mm internal diameter master cylinder. This is a superb improvement and I'd recommend it to anyone. I fitted an AP Racing (Lockheed) 4 pot calliper to my Commando years ago including a braided hose, and this improved things but it always felt like I was squeezing a brick, there was no âfeelâ to the lever at all. Fitting the AN master cylinder has released the stopping power of the calliper and now the brake is as powerful or as gentle as I want. Itâs progressive so moderate hand pressure will gently slow the bike down but I can get the front wheel howling if I squeeze hard. And it looks original too so I can keep my lovely old switchgear.
https://andover-norton.co.uk/en/shop-details/15702
When Norton got together with Lockheed to develop the first disc brake they had to start somewhere and most of us know the limitations of the original master cylinder and disc calliper. Over the years disc brake technology has increased stopping power but of course there is always a battle between that and originality, with each owner having to make up their own mind of how far to go (if youâll excuse the pun!)
Many years ago Iâd heard that a smaller internal master cylinder diameter would improve things and that RGM could fit a sleeve to achieve this. Whilst that is probably fine I would have been worried about the sleeve moving so I never went down that route. Then those fine chaps at Andover Norton produced a master cylinder that had all the right dimensions internally but looked practically identical externally. I bought it a couple of years ago but only got around to fitting it yesterday. I wish Iâd fitted it earlier, itâs very good but I will give you a couple of tips that I discovered on the way. First, make sure you thoroughly clean it out with brake cleaner. I started to assemble the internals with hydraulic fluid to lubricate everything and the dribble of oil had dislodged 3 small pieces of swarf from one of the internal drillings. I collected these and dismantled the piston to make sure everything was OK (it was, but I kept the swarf as evidence). Next I found that my original hydraulic switch would not fit without fouling the step in the casting. A quick trip to Andover Norton and they supplied a new switch which nowadays is a smaller size. I left the swarf and the old parts with them so they can a) improve the cleaning and b) adjust the dimensions so that old switches will fit the new m/c.
interesting reading i am o…
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The superb braking I've n…
The superb braking I've now achieved is with the standard disc, combined with AN small diameter master cyclinder and a 4-pot calliper, AP part no. CP3386 but I donât think they make them anymore (I might be wrong). I got it from AN when they were part of BSA Regal because it utilised the same mounting positions as their âstandardâ racing calliper but I got 4 pot stopping power instead of 2. It doesnât look as good as a traditional racing calliper, itâs very angular with lots of straight lines but, in combination with the decent master cylinder is certainly has much more stopping power than Iâll ever be able to use. Whilst I was at AN they were able to supply a set of new pads for the calliper so even if they discontinue them Iâve got a spare set to tide me over.
No matter what calliper you have fitted to your wheel Iâd say try the new master cylinder because itâs superb. Always use a braided hose, your local hydraulic supplier will be able to make one to suit your requirements.
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A close-up of the 4-pot ca…
A close-up of the 4-pot calliper.
There's no point in showing you a photo of the new master cylinder becasue it's practically identical to the original except instead of having the words "Norton Lockheed" on it it now has "AN" . My wife Ann thinks this means it belongs to her!
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Beauty is in the eye of th…
Beauty is in the eye of the beholder (and function in the hands of the user), but to my mind it seems odd to worry about period style for the master cylinder if one uses Jem's undoubtedly effective-looking calliper.
Apart from anything else, I'm deeply unconvinced by the idea of attaching one's brake lever via the four silly little screws and their not-very-robust threads in the switch body (this goes for drum brakes too, of course).
I like UJM master cylinders of the (approximate) period; cheap as chips and very robust, especially in the matter of attachment to the handlebar. They also don't look too out-of-keeping, at least to my eyes, and often have dog-leg levers.
The one shown in the attached photo is 5/8', so still somewhat wooden even though combined with replica AP calliper; I have a GPz500 one to try when I get round to it, which is 1/2" but has a less-period rectangular reservoir (and a neat mechanical stop-light switch); if you get one from the right year they have adjustable levers.
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Alternative view, showing…
Alternative view, showing the reservoir.
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I find the Andover Norton…
I find the Andover Norton 13mm front brakemaster cylinder works perfectly well with the standardCommando brake disc and calliper, plus it looks good if youprefer to keep things almost original.
As Jem mentions theAN master cylinder releases the braking power, so maybe it's best to try this first before spending money on upratingthe original Norton brake disc and calliper.
The only other mods I have are Goodrich stainless steel braided brakehoses and sintered metal brake pads, the brake has plenty feel and is more than adequate for spirited two up riding.
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Previously gordon_robertso…
Previously gordon_robertson wrote:
I find the Andover Norton 13mm front brakemaster cylinder works perfectly well with the standardCommando brake disc and calliper, plus it looks good if youprefer to keep things almost original.
As Jem mentions theAN master cylinder releases the braking power, so maybe it's best to try this first before spending money on upratingthe original Norton brake disc and calliper.
The only other mods I have are Goodrich stainless steel braided brakehoses and sintered metal brake pads, the brake has plenty feel and is more than adequate for spirited two up riding.
I agree. I first changed the disc to Norvil 12" with AP caliper and braided lines; never having liked the look of the standard disc which had then decided to warp. It gave a significant improvement to braking performance, but still not good enough. Next change was when AN brought out their improved master cylinder and this made a vast improvement. I can well believe the above comment that this change alone could suffice.
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The attached chart and exp…
The attached chart and explanation on the page from www.vintagebrake.com/mastercylinder.htm should give some idea of where to go with master and slave ratios. I have used ratios in the 26-27:1 bracket with very good results in the past.
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interesting reading i am on the verge of going down a similar route, the colorado disc in my opinion looks better and seems well sorted and the price is good all new parts.