13 mm. Siezure

13 mm master cyl. rebore kit decided to nip up today , has this happened to anyone else ? ,about 4 yrs. old methinks. Plastic piston seems to show wear , brake fluid clear yet slightly black from wearing plastic. Seems too soon...

If this happened in direct hot summer sun then may only the tiny extra length of the spacer/plunger between the lever and m/c piston responding to fluid expansion. Otherwise no they should last as long as the factory version when exposed to moisture and time.

To be considered Hobot , braided stainless line ,stainless pistons with new EBC pads all good. Took off 13 mm conversion master cyl. and piston was stuck in bottom of bore. Removed plastic piston showing some wear as say someone put fine sandpaper to it ,bore shows a small amount of wear. Spun piston 90 degrees and re- inserted after cleaning up with fresh DOT 4. Spring returns things now to fully out but a tiny tad jerky. Will re- assemble to braided line tomorrow morn. As long as she returns home I will be happy enough ,but after only a year ? Meet you a the National ? Peter

OH cool Perter, ya learned me something new to look out for ugh. The only thing I can think of to cause you bore bind would be moisture corroding a plain steel piston or if sand paper grit left embedded from a hand hone clean up attempt. Good point to turn piston for new surface, I'd not considered that until your educational alert, which leaves me in good mood to read about you fixing it.

Ugh, don't know if I will come home on any trip but have paid admission for my Mice and Men Plans to attend but may not be able to tow cycle trailer I got 2 wks ago if the lost in shipping trailer hitch don't show up in time to install. Expect more attention to your post once folks return to their work stations.

I rode toady, against my better judgment but got away with it again. Carried my appointment book, big lap top 'puter and charger, box of bungee cords, box of trinkets for Trixie and 3 home made full size french loafs and box with cervical air collor traction I will use on the 2500+ mile trip to Catskils. Maybe I should wear a dead raccoon head on my cap to be recognized?

Hehe my Cdo buddy Wes zipped down his Mt through our village square the bread women said but I missed him on his cute 60 cc bicycle conversion, that just plain goes too fast downhill for bicycle brakes and wheels.

I, too, have had my sleeved M/C sieze up on a really hot day. It required relieving some pressure at the caliper nipple to free it up. Something I will watch from now and forever.

And hobot, I'm seriously hoping to have a beer or three with you in NY. I'm expecting to be there Thurs-Fri and leave Sat.

I'm assuming this is all to do with RGM kits, is that right?

The heated fluid lock up is dangerous if discovered while rolling, especially in parking lots but at any speed. Bleeding fluid is only bandaid as can happen again if d/t the plunger length issue. It was a shock to let out Peel clutch to hit the road to Ohio but instead fell directly on road loaded to the gills and only lucked out I'd put a foot rest bar across the fork brace or bar, mirror lever and tank would have stopped the show 35 mile into 1000 mile attempt. Only way I know to test for this is hair dryer the m/c or leave in hot sun a hour or so and sense the brake drag or lock up, then grind a few 1000th's off the spacer till it just don't.

Looking forward to put faces to the social brains we share here and enough beer to ignore the decades of life's wear and tear.

So Hobot... reassembled Master cyl. again in the hot summer sun and it did indeed lock up in the bore (cleaned and smooth) under the sun again. But not from expanded lever to piston -end clearance but entire assembly-bore-or even plastic piston -seal expansion. Disassembled it from braided line all again and threw it in the refridgerator to see what would happen and the spring load pushed the piston out all on it's own ,no tugging required. So now what to do ? needless to say off the road in the middle of summer. The good news is I have just received my RGM Belt drive and D. Taylor Headsteady with springy device strangeness in the mail after over a month of waiting thanks to the strike. So shiny ,so new, so hard anodized , maybe I should consider the front brake crisis first ? Met a courier once who said "Who needs brakes? "

Really unusual report as usually heat make metal parts swell to free them, especially steel parts surrounded by alloy. I went round and round in past - if heating alloy caused its bores to swell shut but nope bores open up which is why case bearing can just drop out if hot enough. Last thing I expected to hear was new piston sticking as they are kind loose fit with most the bind being the sealing rubber parts. Got light headed on world reality that freezing it freed the thing to spring apart.
Ok I"m stumped too so tingling to learn something new from your show stopper.

Now you know why we (Andover Norton/Norton Motors) use a new Grimeca master cylinder, not a re-sleeved assembly. Our friends at AP indicated this amongst other possible problems. I alone have so far sold over 100 of our kits- Andover Norton have sold more than that in addition to mine- and we have yet to encounter a problem. My son and most of my friends have it on their Commandos.
Joe

Alas its another step away for real Norton and my resleeve factory m/c on Ms Peel worked a treat I liked best of all front brakes tested and no problemo after the plunger/space trimmed just a bit on sidewalk. Its not the most powerful brake available for sure, just the most effective for ABS like action above hwy speed and most saving intuitive brake effort for panic grip action I've experienced.

I have a re-sleaved MC too. On top of the fact that it's a pain to bleed it has been feeling funny lately. 90% of the time it's fine but once in a while it's just a bit spongy. It makes me worry that I could be going 70 mph in a two lane canyon & have it fail & relying on my back brake with the little leverage I get from the rear set peddal could lead to more then just a "Oh SH#+*%t moment. I think you will be getting a order from me Joe.

My records show 4 yrs. old resleeve 13 mm. exchange ,see what happens to memory after thousands of beers ? Still, the bore is clean and smooth and am observing wear on plastic bobbin body only.. This plastic piston rides very close to the bore and am now considering sanding it down to stay off of the bore. You might notice the Norton plunger-piston thingy is recessed to prevent bore contact ,but of course this is steel and would have to be a safe non contact as contact would result in scratching rendering the bore damaged/useless. This is plastic. My original supplier has asked if this is Norvil or Miles Eng. CA. so the story unfolds. Just reassembled in hot sun and she nipped up again ,put assembly in the fridge again and she popped free . Will now google Grimeca and search for an original norton master cyl.in my boxes of bits in the meantime. I know there is a MK111 assembly in there somewhere but will it fit ?

I have the Andover Norton Master Cylinder. It is very good & now have to clean brake dust off the front end now & again.
I am very pleased with it, gives me confidence.
Did think about the resleeve option, but felt a bit dubious about it.

There are different ways of sleeving a master cylinder.
The RGM method has a few potential problems, it can move the position of the two feed/return holes from the reservoir axially along the bore from the original position, the holes in the sleeve can also end up at any position around the bore making bleeding tricky, it uses a Grimeca piston which has a different dimensions between seals and from seals to lever contact point compared to the original requiring an adjuster to try to compensate. I'm sure it's quite possible to put it together and everything work fine but all those slight assembly variations could also add up to trouble.

I went the bonded in sleeve route with a custom piston in the end because it maintains all the critical dimensions exactly as the Lockheed original, so far no problems.

Pulled out my MK 111 master from a box and will try to fit it tomorrow. The handlebar clamp end looks shorter to bar but the good news is I have 2 new Norton rebuild kits but must still dig in boxes to find pistons , hope I didn't toss out years ago from say rust. Just want to get back on the road now. How do I purchase this Gremeca unit here in Toronto ,Canada ? 13 or even 12 mm I hope. Joe?

Turn to one of the Andover Norton dealers or order direct. Currently waiting for delivery of the 100 master cylinders we ordered and paid for in April- Grimeca was under receivership and has now been bought by another Italian company who are gradually getting things back to normal. It appears we were lied to regarding delivery times by the interim regime. All the other components are in stock, so this is the only part that holds things up. Hopefully not for much longer- I have orders here in Germany, so has Andover Norton worldwide.
Joe

Thanks Joe ,found the site. This 13 mm. bore I have is tightly inserted and has not twisted or moved at all ,is circlipped in place too and in good shape ,I wonder if I can just somehow obtain a new piston with seals assembly and try replacing that. Just talked with my supplier and he will have Miles Eng .send up all new internals. Will take some time so will ride the R1100 RT during this period. May have to hit the National on a Beemer because of this ,a big red tourer with Ont. plates . Peter

Miles Eng. asking for everything shipped to Cal. so... can I take the piston/ seals to any shop/store here in Toronto for comparison and immediate replacement ? Honda,Yamaha, BMW ?

Why take chances on something like lining a master cylinder? Appearance wont be the same but a modern cylinder from someone like Brembo or AP seems to me a far better idea?