Rear brake drum (2011)

Hi all

Just wondering if anyone else has had this problem, I was on my Norton the other day when my back brakes locked on and wouldn't free up, I loosened the brake off but the rear wheel was still tight, I was onle about 2 miles from home so I nursed it home but was very hot when I got home, I let it cool down then removed the rear wheel, the brake backining plate was grinding on the brake drum.

After removing the backing plate with the brake shoes I notice the dummy axcile had a lot of end play and when turned over the dust seal was nearly out of the drum, I turned it back over and gave the dummy sharf a hit with a soft face hammer which made the whole drum bearing, seals and dummy sharf to fall out as well the circlip that is surpose to keep it all inside, after cleaning all the parts as well the drum brake housing, I found out what had happen.

What I found was where the circlip sits in its grove the front grove was completely broken away with only a small peice about 15mm left to hold the circlip in place, major failer of the circlip grove, the sprocket and drum is still in good condition and has done over 30,000 miles, the drum bearing is still like new and had plenty of greese as they get service when I fit a new tyre and the parts was in its right order, this is the secon drum and sprocket since new.

The only way I can see fixing this is to get a new drum, or I could weld it and then put it on a lathe and cut a new circlip grove, but still can't see what made this happen, so next time you service your wheel bearings take a good look at your circlip grove to make sure it is still good.

Ashley

PS And this had to happen on a 5 day long weekend

ashman said:

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The only way I can see fixing this is to get a new drum, or I could weld it and then put it on a lathe and cut a new circlip grove, but still can't see what made this happen, so next time you service your wheel bearings take a good look at your circlip grove to make sure it is still good.

Ashley

PS And this had to happen on a 5 day long weekend

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I think this is a known issue. Did you happen to take pictures?

Hi Dave

I will get some pics in the next few days and post them up, I have had my bike since new and have done well over 100,000 miles, my orginal drum wore out the sprocket and never had any problems with this happening, just wondered if any one here had the same problems...

Ashley

i've a drum with the meat beyond circlip groove gone, it now helps hold a tarp over my lawn mower along with another drum the teeth dissolved running chain too worn. You lucked out dumb axle held up and still may be suspect to re=use and highly suggest it mag fluxed and even cryo tempered. When the axle clamp force leaves the axle can let RH side of axle go back to end of slot and tip rear tire for rear steering wonders. Safety wiring that side against adjuster ain't a bad idea. Drive chain mostly hold that side against adjuster.

I had the circlip come out of place causing the drum to rub against the backing plate which wore off the metal at the side of the circlip so that when I tried to reinstall the circlip the last thickness of metal popped of. Scrap drum.
When installing circlip check to be sure its sharp edge is to the outside and double check it is seated.

My god, the more I learn the more scared I get. I just did 300 miles battling horendus winds & a bit O rain to enjoy a great ride through the mountains and I really need to be able to start the things pump a pumpin and go off into the sunrise without being worried the wheels are going to disolve... Geeez got to go, I need to get to the hardware store before they sell out!

I really need to be able to start the things pump a pumpin and go off into the sunrise without being worried the wheels are going to disolve...

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hehe Norton Commandos are a real man's hobby to me, wisdom to know how fragile these things can be yet courage to ride far away non the less - and do it again after some surprise let goes just behaving normal : )

I've been at is 12+ yr now and its a thrill each time to twist up the throttle and it just scoots ahead and not make me call for a pick up. Cell phones don't work much of where I live and ride, so extra thrill leaving w/o many tools and faith someone will notice and call for ya : )

BTW lovely blue frame you can look through to other side. I'd love to see a full size side view to understand how ya got it like that.

Hi All and GTSum

My 850 has been in a Wideline Featherbed frame for 30 years now but I run the Commando front end and rear wheel, in all that time its been running I have never had a break down that I couldn't get home on the bike, I have always carried tools in my shoulder bag for most of the time and have never used them, but since the rebuild and back on the road for 5 months now I haven't carried my tool bag, just a srcew driver in my jacket pocket for some carbie fine tune ups, so maybe I should start taking my tools with me again as I don't seem to have any problems when I do have them with me.

Just do your maintenance when needed and enjoy riding you pride and joy with out worring about break downs as any bike can break down at anytime, its just the way things happen with any thing man made, just put your trust in the hands of the Norton Gods, after I fix this up I will be doing a few long distance rides, hopefully before this next weekend as its another long weekend as well I have a extra day off so 4 days of riding.

Ashley

I have had the circlip come out of the brake drum slot ,plenty of rubbing sounds limping home. Then the new sprocket drum had the slot machined too tight to accept the new circlip so carefully filed the circlip a bit to drop home. So be it.

Never had an issue, but I have heard of some sub-quality India-made drum/sprockets out there. Could these be some of those?

Snap rings are made by stamping from sheet. They have two sides and can be installed backwards (really). Have a close look and you will see that one face will have sharp edges and the other will have a very slight roundness to the edge form. They must always be installed with the sharp edge facing out or there is the possibility of failure due to the ring becoming unseated from its groove. Real ugly in pistons. Also, if a snap ring has been deformed even slightly, there is a good probability that it may become unseated. I generally give the snap ring a series of gentle pops around the perimeter with a hammer and pin punch to ensure that is is really seated in its groove and not being held proud of the groove by what it is retaining. For what it's worth.

Hi All

The circlip was put in the right side with the sharp edge facing out, I always make sure this is done right every time I use them, I took the drum to work today and set it up on the lathe, got it spinning on slow speed and as close to true running as possiable, with a inturnal cutting tool holder with a nice sharp tip I started to cut what was left with the old circlip groove and machined it deeper, I had a circlip kit at work and with luck the biggest circlip in the kit with only one left that size was just a bit bigger than the orginal circlip, it fitted in and still wide enought to hold the bearing and seals in place and it seems it will hold, as well I will put some Locktight shaft sealant on the outer bearing so once fitted it shouldn't move in the housing.

What have I got to lose as my sprocket is still good and my local British bike shop here wants $200 for a new drum, but I will be ordering a new one from England and with shipping will be still way in front from my local shop and knowing its British made not some thrid world cheap copy, I will let you know if this works.

Ashley

Way to go Ashley,
A bit of skill on the lathe and she should be apples mate. Now from your post's I can't imagine you would be running your chain out of alignment, but I would guess this could help to add side load and possibly pop the circlip?

Cheers Richard

Hi Richard

I have been running the Featherbed frame and 850 this way since 1980 and its the first time this has happen, my first sprocket wore out and never had any problems with the circlip and this drum/sprocket has done about 40,000 miles, my chain runs pretty much strait so I think it was just one of those times when somethink goes wrong, maybe my rear wheel didn't like all the attention my front end has got over the last few weeks, I just upgraded my front brakes to a full Grimeca 12"floating brake system and Master cylinder.

I fitted the new bigger circlip last night but still a little lose so will get the next size up from this one and it will still hold the bearing and seal in its housing, will let you all know how it will go.

Ashley

Hi All

Have the drum all back together now, had to get a 42mm cirlip to fit in the new circlip grove, fits nice and tight in the grove and has plenty of meat to hold in place, I can't see this happening again, will be taking the bike for run today so this will be the big test but I won't have no more problems with this again, but I have just ordered a new drum and new brake shoes from England, I will keep it in my spare parts box till needed.

Will let you all know how the ride went when I get back home.

Ashley

Hi All

Well I rode the Norton today and did just over 100 miles with out any problems, so I am a happy chappy again and it only cost me $3 for a new circlip, it only took me 5 minets to set up on the lathe and about another 5 minets to machine the grove deeper so it has been a cheap fix and I think it will last till the sprocket is well worn.

Ashley

Hi All

Have had the repaired drum on the bike for 2 weeks now and have riden the bike every day since, have had no more troubles with it so far, so this was a easy fix for me, 5 minets to set the drum up on the lathe, 5 minets to machine the circlip grove deeper and $3.50 for a new circlip, love it when things go to plan, the weather here is starting to cool down a bit now as we come into our winter, the Norton runs so much better when the temputure drops, cool days and cold nights, just right for riding, we don't get snow here so its just right for the Norton.

Ashley

ashman said:

........ the weather here is starting to cool down a bit now as we come into our winter, the Norton runs so much better when the temputure drops, cool days and cold nights, just right for riding, we don't get snow here so its just right for the Norton.

Ashley

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Lucky blokes.

Dave
69S

Well its been over 3 years now that I did this repair and after 18,000 mile it is still going well, I have a new sprocket sitting under my work bench since this problem happen and so far haven't had no need for it

This was the repair.

Ashley

ashman said:

Well its been over 3 years now that I did this repair and after 18,000 mile it is still going well, I have a new sprocket sitting under my work bench since this problem happen and so far haven't had no need for it

Ashley

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You could sell it for a nice profit, but then your current drum would explode all over the highway right after that! Happy to know it's been working well, but it still bothers me to not know what caused the failure in the first place.

Nathan