Rear Drum Improvements?

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Tornado

Tornado

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Found a local shop doing brake shoe re-linings and other work. What should I ask them to do for a reaar drum brake on my Commando? It has always been vague and squishy on the foot lever and it continues to be slightly out of round/uneven, even when holding brake on fully while doing up the rear axle.

Currently running Emgo shoes (new last season). Drum has 20k miles and I have a fresh drum to fit if current one is done.

Shop was mentioned on Paul Brodie's YouTube recent video on his Triumph Cub brake upgrades.

Brake & Rotor Machining Vancouver | Saw Guides B.C. | Senco Brake

www.sencobrake.com www.sencobrake.com
 
Have them turn the drum and then match the shoes to the drum. The entire surface area should contact the drum when applied.
My 73 Mk1 has always had a rear brake that will lock the tire up at road speeds when enough pressure is applied.
 
I fitted RGM rear shoes with MZ high friction gold. It was a mission because they needed to be arced on a lath before they would fit in the drum.

But it is now the best rear brake I have ever used. Much much much better than the mussy ineffective Andover shoes
 
johnm said:
I fitted RGM rear shoes with MZ high friction gold. It was a mission because they needed to be arced on a lath before they would fit in the drum.

But it is now the best rear brake I have ever used. Much much much better than the mussy ineffective Andover shoes
Click to expand...
Mine fit in my drum fine. Arced them by hand with some sand paper taped in the drum and ran the bike in 1st on the stand, and then everything got a good clean and lube.

So I think YMMV wrt the MZ Golds fitting out of the box.
 
Check wether the brake plate is not warped/bent. In other words wether the pivot pins of the shoes are in lign with the rear axle.
Just found out, using a lathe, mine were not.
Maybe after the rear axle broke.
Also, the brake cam bearing stay and its thick spacer were not seating flat on the plate centre, needed 0.5 mm shim.
There are a lot of tiny surfaces there that get tightened up along the rear axles which may frustrate alignment.
That apart from the alignment in the swingarm pads itself.
 
A lot of problems with rear brake is cable problem related, but the rear brake is to slow the rear wheel down when using the front brakes as we all know the front brake does all the hard work.
I am still using my original rear brake shoes and can still lock up the rear wheel if need to but I don't, even with my modern Triumph with rear disc working both front and rear brakes the front still does all the hard work of stopping and when riding I hardly use my brakes only for stopping mostly when pulling up and use minimal brakes while up in the ranges and I do the same when out in the car or truck and I use to drive heavy trucks and dog trailers towing Bob Cats and other machinery you learn to look after your brakes and same with riding.

Ashley
 
Sorry if the answer to these questions are very obvious to many of you, but...
If a lathe is used to ensure "correct" arc:
A) What do you use for centre?
B) How do you mount the brake plate in the lathe?

@johnm - did you do yours' or job it out?
Cheers
 
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I turned down some 5 centimeters of the thread of about 15 centimeters length of M20 threaded rod.
The brake plate was fitted to the rod using 2 nuts and 2 thick flat washers.
Rod with brake plate was clamped in the chuck.
With the tip of a dial indicator perpendicular against the inside of the plate, close to the outside diameter, by turning the chuck by hand I checked the straightness.
Also visually wether the 2 pins were in lign with the bed of the lathe.
It was quite easy to bend the plate a bit with a short length of wooden beam as lever.
 
I had similar issues on my own bike's back brake, got fed up with trying to make it work well and recently went with the Madass/Don Pender rear hub setup and that fixed it...that also got me a safer one piece axle and a non-ridiculous cush drive among other things. A drastic fix and cost $$$ but well worth it, wish I'd done it much sooner. Moving the rim and spokes over to the new hub was easier than I expected and went well. Anyway something to consider if all else fails...

Rear Drum Improvements?
 
bluto said:
I had similar issues on my own bike's back brake, got fed up with trying to make it work well and recently went with the Madass/Don Pender rear hub setup and that fixed it...that also got me a safer one piece axle and a non-ridiculous cush drive among other things. A drastic fix and cost $$$ but well worth it, wish I'd done it much sooner. Moving the rim and spokes over to the new hub was easier than I expected and went well. Anyway something to consider if all else fails...

Rear Drum Improvements?
Click to expand...
Looks good, although I'm not sure how that eliminates the need to skim new shoes to match the drum?
Cheers
 
robs ss said:
Sorry if the answer to these questions are very obvious to many of you, but...
If a lathe is used to ensure "correct" arc:
A) What do you use for centre?
B) How do you mount the brake plate in the lathe?

@johnm - did you do yours' or job it out?
Cheers
Click to expand...
Hi. Trying to remember. It was done on a friend's lath. From memory we made a short stub axle centred on the brake plate and clamped the plate. Then assembled the shoes and springs. Normally we spaced out the shoes using spacers on the cams but for these shoes they were already too big to fit in the drum so I think we just arced them to the drum internal diameter. Very slow rotation. Also dressed the leading edge of the lining.

I added rivets too which is probably unnecessary but I once had a glued brake lining come off so I now always add some rivets.
 
Thanks for advice here. I have made a centering device using the short dummy axle and a piece of thick-walled aluminium tube.
Tightens up nicely and spins well in my drill press (don't have a lathe)
I have ordered some RGM MZ Gold shoes and will have them turned to match drum when they arrive.
Sorry for the partial hijack @Tornado !
Cheers ;)
 
Have them turn the drum and then match the shoes to the drum. The entire surface area should contact the drum when applied.
Click to expand...

Rear Drum Improvements?


At Your Service !

A used drum will have heat cycled , so should hold true after skimming ( we hope ) .
Was a artical on the racing brake service bloke in something once .

Id check the brake plate , for trueness and wear . a bar through the spindle hole
would see if its twisted . a bias before lever goes on so pressure gets it true ,
would be better than bent pasdt square - perpandicular .

the fit of the brake cam , and lever , if your playing Stirling Moss ( He once had one )
plus cleaning - blowing through , the cable , and if its not nylon innered , saturate lube
& hang to drip clear .

Some twit had a Honda 750 rear wheel on a Commando to get a decent cush drive .
Youd think the crankshaft or clutch would be where to put it though , but if you must fiddle ,
this bloke looks like He's done something sensable , and the cable operation dosnt make it
harder , swapping sides like that .

Rear Drum Improvements?
 
A friend who races a couple of Seeleys (920 & 1007) runs Suzuki rear hubs.
I went for a Maney/Minnovation cush drive sprocket and T140 rear hub & disc on my Mk4
I used EMGO shoes originally on my 850, and they're actually not bad. However, I switched to Ferodo which were noticeably better. Didn't stop the spongey feel, but given the length of the lever I guess it's just a function of the design?
 
I do find I need to push the foot pedal further down than my foot wants to do hinge to get significant braking on the rear. A good part of this is needing to have the adjuster set to give enough slack to prevent brake binding at certain points as wheel rotates. So a "centering" trued shoe/drum assembly should improve this. But I also note my foot rest and pedal land is a little tilted above being square to primary case. Is that normal or evidence of some previous bending from a tip over?
 
Tornado said:
I do find I need to push the foot pedal further down than my foot wants to do hinge to get significant braking on the rear. A good part of this is needing to have the adjuster set to give enough slack to prevent brake binding at certain points as wheel rotates. So a "centering" trued shoe/drum assembly should improve this. But I also note my foot rest and pedal land is a little tilted above being square to primary case. Is that normal or evidence of some previous bending from a tip over?
Click to expand...
FWIW my bike needed too much rear brake cable slack too for the same reasons and the new hub a few posts up fixed that, no more drum wobble and the brake plate centers better....that being said from what I've read here some get the stock setup to work fairly well. I wanted a one piece axle and a better cush drive also so that is what made me decide to go with the new hub instead of continuing to try to improve the stock setup...
 
Tornado said:
I do find I need to push the foot pedal further down than my foot wants to do hinge to get significant braking on the rear. A good part of this is needing to have the adjuster set to give enough slack to prevent brake binding at certain points as wheel rotates. So a "centering" trued shoe/drum assembly should improve this. But I also note my foot rest and pedal land is a little tilted above being square to primary case. Is that normal or evidence of some previous bending from a tip over?
Click to expand...
The shorter lever on my rearsets helped with this. I know technically it reduces leverage but it doesn't seem to have affected braking power.
I expect even better with new shoes turned to match the drum.
Rear Drum Improvements?
 
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