How to remove broken axle??

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Wicks

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Nov 25, 2012
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Hi all, new Commando owner here. The bike is in pretty good shape, but I took it for first ride, and the rear brake nearly caught fire (1975 MKIII). :( Rear disk nearly ceased in the caliper, so I began to remove real wheel to assess. Removing the axle nut, and turning the axle bolt head, the threaded end didn't move. Can't pull or tap either end to withdraw from the wheel - any suggestions how to get this rear end apart? Much thanks...
 
Welcome to the forum, Wicks.

Wicks said:
Removing the axle nut, and turning the axle bolt head, the threaded end didn't move.
Click to expand...


The Commando rear axle is in two parts.

First you unscrew the main axle and withdraw it from the right side, you should then be able to remove the wheel, leaving the sprocket assembly attached to the swinging arm by the 'dummy axle' however it would appear you have have removed the nut.

Before you do anything else I suggest you read the relevant section of the workshop manual:
http://britmoto.com/manuals/Manuals/850_man.pdf

A dragging rear brake on a MkIII is often caused by a faulty or incorrectly adjusted master cylinder.
 
Ugh, Norton dumb asxles are actually a radioactive element with a half life of about 40 yrs so some percentage will break each year given enough time no fault of your own. Yours may be the 4 or 5th I've read of last 1.5 yr, mine was one of em. The DS nut only releases the stub axle which the long fission prone axle threads into. When threads shear off it leaves the broken piece loose inside the subby axle but then no thread force to back out long axle past its binding in all the spacers. Somehow must grab end of long axle or pry under its head to work on out then the rest will fall apart all by itself. A meaner assualt may require welding some on end to grab on to to whack out with a hammer slide puller or such. May have to unload wheel with rag under of bungees over to untrap axle or just ride of a bit and it may work out a inch or more which makes slow speed control very dicy but not too bad once over 15-20 mph, till slowing down again ... whoopeedoodie. I just stuck a new axle in mine but should of sent off to have cryogenic tempered first but during winter down time I sure will. Madass sells a one piece that's likely fine for ever more and may end up with one if my 3rd axles fissions. Road side tire fixes are not as easy with one piece but maybe ok with a sitck stuck in drum to hold up while inserting the real axle.

May need to tack weld the drum paddles on wheel hub side once exposed and found wiggly or as preventive.
 
Wicks said:
Hi all, new Commando owner here. The bike is in pretty good shape, but I took it for first ride, and the rear brake nearly caught fire (1975 MKIII). :( Rear disk nearly ceased in the caliper, so I began to remove real wheel to assess. Removing the axle nut, and turning the axle bolt head, the threaded end didn't move. Can't pull or tap either end to withdraw from the wheel - any suggestions how to get this rear end apart? Much thanks...
Click to expand...


On a previous MK III that I owned it was possible to thread the master cylinder too far into the receptacle that holds it in place, by a turn or two at the very end. If this mistake is made, then the brake pucks will not release after the pedal has been depressed -- which meant the only way to release the brake was to crack the bleed nut on the caliper. When I experienced this problem the brake was fine until used once, and then would rub until it got so hot it would begin to drag -- or drag so much that I would begin to notice.

As I think about it now, I can't remember if I ever thought about it logically as to why it was possible to bleed the brake, but it was. Anyhow, if you end up taking the master cylinder apart, make sure to figure out that your reassembling it the correct distance into the threaded metal receptacle. If I recall correctly, on my old bike the correct distance was all the way in and then a turn or two back out.

Of course not all bikes are the same, so on yours it might not be possible to have the above described situation occur.

As far as testing it cold on the center-stand, I don't remember if it grabbed enough to stop the wheel from moving, or if it only held it tight enough that the pucks got hot, and then maybe caused the brake fluid to expand as it warmed. Too lazy to figure out right now if brake fluid expands when warmed. If I was guessing I'd think it wouldn't ...
 
Wicks said:
Hi all, new Commando owner here. The bike is in pretty good shape, but I took it for first ride, and the rear brake nearly caught fire (1975 MKIII). :( Rear disk nearly ceased in the caliper, so I began to remove real wheel to assess. Removing the axle nut, and turning the axle bolt head, the threaded end didn't move. Can't pull or tap either end to withdraw from the wheel - any suggestions how to get this rear end apart? Much thanks...
Click to expand...

STOP! Get a manual.
 
hobot said:
Ugh, Norton dumb asxles are actually a radioactive element with a half life of about 40 yrs so some percentage will break each year given enough time no fault of your own. Yours may be the 4 or 5th I've read of last 1.5 yr, mine was one of em. The DS nut only releases the stub axle which the long fission prone axle threads into. When threads shear off it leaves the broken piece loose inside the subby axle but then no thread force to back out long axle past its binding in all the spacers. Somehow must grab end of long axle or pry under its head to work on out then the rest will fall apart all by itself. A meaner assualt may require welding some on end to grab on to to whack out with a hammer slide puller or such. May have to unload wheel with rag under of bungees over to untrap axle or just ride of a bit and it may work out a inch or more which makes slow speed control very dicy but not too bad once over 15-20 mph, till slowing down again ... whoopeedoodie. I just stuck a new axle in mine but should of sent off to have cryogenic tempered first but during winter down time I sure will. Madass sells a one piece that's likely fine for ever more and may end up with one if my 3rd axles fissions. Road side tire fixes are not as easy with one piece but maybe ok with a sitck stuck in drum to hold up while inserting the real axle.

May need to tack weld the drum paddles on wheel hub side once exposed and found wiggly or as preventive.
Click to expand...


From his post it appears he undid the left-side nut and didn't know that the right-side bolt is not a one-piece that protrudes out the left-side. He probably doesn't have a broken axle. Your advice for meaner assaults and welding would probably send him off on the wrong path if there weren't others replying.


And unless Madass has recently changed his product offerings, his one piece axle is not available for MK III bikes.
 
Ok granted its possible that the stub and long axle are both turning together with the DS nut undone. Would make sense as one axle fractured the clamp force lost and TS axle slides to the rear of axle slot as it works its way out all by itself. Alas I only really know Combats [cream of the crop], but learning more about why I don't desire factory 850's all the time here. I still have good respect of a loaded down well ridden 850 in Mt roads as rather tough to follow even on my modern 70 hp race tired suspension upgraded SuVee, just not as handly when I've played an 850 on and off road some.
 
hobot said:
Ok granted its possible that the stub and long axle are both turning together with the DS nut undone. Would make sense as one axle fractured the clamp force lost and TS axle slides to the rear of axle slot as it works its way out all by itself. Alas I only really know Combats [cream of the crop], but learning more about why I don't desire factory 850's all the time here. I still have good respect of a loaded down well ridden 850 in Mt roads as rather tough to follow even on my modern 70 hp race tired suspension upgraded SuVee, just not as handly when I've played an 850 on and off road some.
Click to expand...


My guess is that he simply hasn't tried throwing a wrench on the axle yet. Probably took off the bolt on the left and started tapping or hammering on the left side trying to jar the axle free, not realizing it's threaded. Hopefully he wasn't swinging too hard.
 
hobot said:
Ok granted its possible that the stub and long axle are both turning together with the DS nut undone.
Click to expand...

Only, Wicks said: "Removing the axle nut, and turning the axle bolt head, the threaded end didn't move." Which is likely even if the nut had been removed because the flats on the part of the dummy axle that rests inside the adjuster slot would still prevent the dummy axle turning.
 
Thanks all - I read about the two pieces axles (on "earlier models") somewhere, but rechecked the manual I am looking at and it clearly shows a one-piece axle. Funky. If it is correctly two piece, I guess my first problem is how to withdraw the main (right) axle, unscrewing it doesn't make it come out. Hangs at about 1.5" between the swing arm and bolt head...
 
Wicks said:
Thanks all - I read about the two pieces axles (on "earlier models") somewhere, but rechecked the manual I am looking at and it clearly shows a one-piece axle.
Click to expand...

I can assure you the MkIII also has a two piece rear axle which is what is shown in the manual and parts book.

http://www.oldbritts.com/1975_g23.html
Items 26 & 29 (The exploded drawing of the rear wheel in the manual, Fig,H3(a) is more accurate than the parts book drawing)


Wicks said:
If it is correctly two piece, I guess my first problem is how to withdraw the main (right) axle, unscrewing it doesn't make it come out. Hangs at about 1.5" between the swing arm and bolt head...
Click to expand...

Have you slackened off the R/H lower shock mounting bolt? As that loosens the caliper mounting plate and may help you get the axle out.
 
Wicks said:
Yes - I have, still won't back out more...
Click to expand...

Are you supporting the wheel? If not, with the axle partially withdrawn the weight of the wheel could be trapping the axle.
 
Yes - working the wheel up and down to try to help loosen... turning the page in the manual reveals the "dummy axle"...if only in the former pages "the axle" had been referred to "the main axle" or "the right axle" or anything, even "the trick axle" would have triggered it. 40 bikes, first one with a split axle.

Should I rig up my winch onto the main axle and put the bike between two close trees? ;)
 
The point of the two-piece axle is that you can remove the wheel and leave the brake drum and chain sprocket in place.

Some like it, some hate it
 
I would love it if it worked. :) Anyone with bright idea on how to get the (main) axle to withdraw?
 
Place the nut back on the LH axle stub. Make sure the wheel is supported and that you can wiggle it around a bit. I suggets you drop/move the caliper out of the way so that it is free of the rear wheel rotor. If the axle is now in a bind, unbind it and take your time trying to assess where it is hanging up and why. Something as simple as the MkIII axle slack adjusters can cause the axle to bind a bit.

Once the axle is unbound start turning and tapping it out - this is where you need to get a bit creative. This may take two people, one turning the axle while one taps an adjustable wrench shouldered beneath the head of the axle. No need to use excessive force here...yet. More of a learning and discovery process now to sort out what is going on in places you cannot see.

Things that could be holding up the axle are rust or other corrosion, bad burr on axle, chain adjusters.

Take your time on it and walk away now and then. Cooler heads most always prevail.
 
Oh ugh LAB i must of been groggy not to remember the stub axle has flats that trap from turning. Just had Trixies out a couple days ago and noted the flats to align on refitting. Only thing I can think of that might trap the long axle in same thing that can trap swing arm spindle, something spining/rubbing axle wore a grove or a lip that hangs up. Usually can twist the shaft so lip clears - unless too much lip like my two spindles - then you don't wouldn't believe how I got em out. i can't think of what might grind on axle to lip it though. If long axle turns it should back itself out at least an inch then pretty much hand pulls out with some wheel slack jiggle.

40 bikes and your first Commando mere axle has stumped ya, just wait till your really dig into it. There is a reason many endure what it takes to get a fully fettered Commando, but i've run screaming out into the dark more than I care to count. Some times its seemed only the collective mind force of group altered reality so something stuck-fused came apart of went back together as expected.
 
Agreed, & while my experience with Q.D. hubs has been BSA/Triumph, I do also sometimes wonder if certain types of British mechanical design & practice are really the work of entities from the 5th [or further] dimension sent to screw with us...
 
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