Maillard drum brakes

[Invicta Tourist]

The front brake on our tandem has a Maillard drum brake. When I apply the brake, it is very poor at stopping the tandem. Nothing seems to be obviously broken and the brake doesn't squeal. The back drag drum brake stops the tandem quite well by comparison.
Does the front brake need dismantling or parts need replacing? Any tips/hints on how to do this would be appreciated.

[531colin]

This is the only picture I could find...
Its from Wiki., so its a car. there are 2 brake shoes, with a common pivot at the botton, and a brake cylinder at the top which pushes the shoes apart. The tandem will have a cable operated cam here.
The rotation of the drum pushes one shoe harder against the drum; this is called the leading shoe, it wears faster than the trailing shoe and does most of the braking. Theres the rub...you have to have some "float" in the system, otherwise the leading shoe wears and stops working, and you are down to the trailing shoe, which is pitiful. The float may come from 2 places, float in the shoes' common pivot fixing to the brake plate, or float between the brake plate ( the bit holding the shoes etc, in a bike brake) and the axle.

To get into the beast, there is usually a cone locknut's cousin holding the brake plate onto the axle.
I suspect all you need do is restore the float; you may be able to reverse the shoes to even up the wear.

[snibgo]

My ancient car had drum brakes. She did low mileage, so the usual problem wasn't wear, but the shoes becoming old and hard, thus ineffective. So the shoes needed replacing every 5 years or so.

I don't know if bike drum brakes are similar.

[gaz]

Googling has helped me find some servicing instructions for Arai drum brakes.

Of note is an expected life span of 20 years (1,000,000 miles) and the fact that the pads may contain asbestos.

[thirdcrank]

I'm not sure, but I think that Maillard stuff is a prededecessor of the Sachs - now called SRAM.

If so this is the current rather minimal instructions (scroll down for the English.)

http://www.sram.com/_media/techdocs/VT5 ... 0_6_04.pdf

I have two of these front brakes - and compared with modern bike brakes they are in chocolate teapot territory. I bought both mine to get better weather proofing rather than spectacular brakes. I'm not sure if you have noticed a deterioration at the front over a period or if you are simply comparing it with possibly a different make of drag brake. Unless that's the case, it may be that there will be little improvement possible.

[Invicta Tourist]

Thank you for your replies and suggestions on how to repair this brake. Perhaps I'm being rather cautious at the moment, but hearing the word 'asbestos' in relation to doing any bike maintenance makes me wonder whether it would be better to leave any repair to someone with the necessary lung protection!

[531colin]

Thank you for your replies and suggestions on how to repair this brake. Perhaps I'm being rather cautious at the moment, but hearing the word 'asbestos' in relation to doing any bike maintenance makes me wonder whether it would be better to leave any repair to someone with the necessary lung protection!

In my lifetime asbestos has gone from being an everyday material to something which generates reactions bordering on hysteria.
Yes there is a hazard, if you work with the stuff 40 hours a week, for a number of years, in a way which generates significant amounts of dust of respirable size, and if the asbestos in question is one of the (minority) dangerous ones.
If you are doing the odd bit of DIY, I dont think its a problem.

Friends of mine grew up in asbestos prefabs in post war bomb damaged London. We all used to blow the dust out of our motor bike or car drum brakes in the days when the linings certainly did contain asbestos. A friend of mine died from asbestos related lung disease. He had been a fitter in the Navy, in the days when you insulated pipes by mixing asbestos wool with plaster, then (when you had finished chucking it at your mates, etc.) you added water and patted it round the pipes. Then he became a gas fitter, still in the days when asbestos was treated as safe. On building sites, asbestos containing materials were sawn and sanded using power tools - thats now (rightly) illegal, but I dont remember hearing of an epedemic of asbestos related deaths.

End of rant...its up to you of course. Does the LBS have a respirator? what do you think?

[thirdcrank]

, but I dont remember hearing of an epedemic of asbestos related deaths....

Here's one

http://en.wikipedia.org/wiki/Armley_asbestos_disaster

(I'll admit to being sensitive about this - I lived within that yellow box from being born until I was 9 )

I see that the HSE is talking about roughly 4,000- asbestos related cancer deaths a year.

http://www.hse.gov.uk/statistics/causdi ... hseopinion

[531colin]

Ah, yes, "Armley snow" they called it, a friend of mine now living in Harrogate grew up in the Armley snowfall area, she only moved out when she got married. You must have been neighbours.
I'll have a look at that other stuff, but 4000 deaths a year sounds like occupational exposure, if it was occasional exposure when changing your brake linings, I think it would be more.

EDIT They are talking of roughly 4000 asbestos cancer deaths per year, made up of a fairly accurate number of mesothelioma deaths (the typical asbestos tumour, rare in un exposed people) and a guesstimate of other lung (etc.) tumours attributable to asbestos, but clinically indistinguishable from, say, smoking induced disease.
In a separate section, they go on to list the occupations most at risk of mesothelioma, there are many building trades listed. To me this infers that the 4000 deaths are from occupational exposure, but this is NOT stated, that I can find.
another EDIT. Motor mechanic is not a listed occupation

[Ian Aldridge]

Ho Marie1
Did you ever get your maillard drum brake fixed? We've got a tandem with a rear drum brake with much the same problem as yours had and would love some ideas on where to get new bits from.
Cheers

[gilesjuk]

Drum brakes offer one advantage, they are sealed from the elements. Other than that they are worse than rim and disc brakes. As the drum heats up it expands and moves away from the pads. With rim and disc brakes the rim or disc expands against the pads, so it helps with the braking.

[thirdcrank]

Ho Marie1
Did you ever get your maillard drum brake fixed? We've got a tandem with a rear drum brake with much the same problem as yours had and would love some ideas on where to get new bits from.
Cheers

i posted above that Maillard was a predecessor of SRAM. I've no knowledge of what has changed with these brakes over the years, but I doubt it is much, if anything. As you may have found, the first problem is to get a bike shop that will take an interest in drum brakes. (Sharp intake of breath, then "Where did you buy that? etc.) I'd recommend Cycle Heaven at York. http://www.cycle-heaven.co.uk/ No connection except as a customer. Like most bike shops, they can be a bit idiosyncratic, but they've always come up with the goods and the know-how when I've needed anything to do with hub brakes etc. No doubt there are others.

SRAM's distributor is Fisher Outdoor. This type of equipment is SRAM Leisure; I fancy it only forms a tiny part of their business. I see they have a 'Leisure' brand manager. It's not a service I've tried but if I had questions like this, it's where I'd start. http://www.fisheroutdoor.co.uk/ContactB ... asp?id=360

[MikewsMITH2]

These brakes just aren't very good! Regular adjustment and lubrication of the pivots helps as does regularly"busting" the gaze on the shoes with a sandpaper (wear a dust mask) and also roughing up the drums with glasspaper. If you've overlubed the hub at any time the oil can get past the felt seal and contaminate the drum. In which case you need to degrease. The Arai ones however which look to have the same internal design work very well

[rjb]

+1 for what Mike Smith says, roughen up the braking surface of the shoe to remove the glaze works quite well. I use a wire brush ( and do it outside and wear a mask or hold your breath if worried about asbestos ).

[hubgearfreak]

These brakes just aren't very good!

that's counter to my experience