Drum brakes. I hate them.

ItDontGo · Post by **ItDontGo** » 25 Jul 2005, 04:00

Any tips on getting my drums off on the AX? They catch in the shoes.
I followed the Haynes manual tip but couldn't find where to stick the screwy.
I hate drum brakes

I hate drum brakes

AndersDK · Post by **AndersDK** » 25 Jul 2005, 04:16

Dont we all hate drum brakes [:(!]
Do a search on drum brake. I'm sure we have lots of previous postings on the subject - even the one with the hint you need now ...

2ndtonunn · Post by **2ndtonunn** » 25 Jul 2005, 04:20

If you end up levering the drums off, make sure you have a new set of shoe retaining clips, they will get broken.
Once you have the drums removed grind off the wear ledge around the inside outer edge, that will prevent the problem next time.

jeremy · Post by **jeremy** » 25 Jul 2005, 04:46

I expect that you can unadjust the brakes by poking a screwdriver through one of the boltholes and pushing the ratchet wheel round.
Jeremy

jeremy · Post by **jeremy** » 25 Jul 2005, 13:47

I'm curious that the drum brake hasn't been confined to the great historical scrapbin. I find arguments as to cost hard to understand as there are so many components in a drum brake, that all have to be machined as well as assembled presumably by hand. By contrast the disc brake is fundamentally castings which would lend themselves to being machined on automated machinery and while things like BX/ZX handbrake mechanisms are difficult to overhaul and re-assemble they are probably very easy when new on a bench.
My theory is that material costs are largely immaterial, its labour, transport storage and distribution that cost money.
Jeremy

Post by **Peter.N.** » 25 Jul 2005, 14:15

Drum brakes were all we had until the advent of 'power assistance' with a few exceptions, notably the Hillman Super Minx which had non assisted front discs and you almost had to brake with both feet! because they need less effort to operate they make a better handrake but its probably a matter of cost as Jeremy says as most top spec cars have discs. Drums are probably overall lighter and use less metal as the only heavy component is the drum.

Kowalski · Post by **Kowalski** » 25 Jul 2005, 14:24

I think comparing like with like (in terms of braking performance) discs are much lighter than drums. Drums need to be bigger than discs to give the same performance and brake calipers on cars can be made of aluminium for lightness. There probably is not in it though, I'm sure if drum brakes performed better they'd be using them in motor racing.....

jeremy · Post by **jeremy** » 25 Jul 2005, 14:31

Drums could be highly effective but were always prone to fade and i don't think many if any of the solutions really worked.(I'm talking 'Alfin?' alloy finned drums and so on.) Rolls Royce only went to discs with the Shadow in about 1966, having used a curious arrangement of 3 trailing shoes on the front of the Clouds. (presumably avoided the grab from a rusty drum on first application)
The handbrake was always a problem but my Daimler 250 V8 (really a Mk 11 Jaguar with a crinkle cut radiator) has the Dunlop system which originated in the late 50's and worked rather well when overhauled - so I really think everyone made a meal of that argument.
I suppose the really interesting one is the BX 14 which has the same brakes as all the otheres except the 16 valve - and even then the pads are common all round. Had there been a significant saving in the cost of a non-handbrake drum brakes the poor thing could have had rear drums.
jeremy

Kowalski · Post by **Kowalski** » 25 Jul 2005, 14:52

Top Gear were doing a "restoration" vote thing, one of the cars you could vote to have restored was a Lotus built for James Dean but not delivered before he died. At the time Lotus were using disc brakes on their racing cars but this car made for James Dean didn't have the discs, it had inboard drums with fins on them, they didn't look rusty so they could have been alloy. At that time Lotus were very secretive about the brake disc technology they had for racing and because the car had to have the discs removed and drums put in instead, it's delivery was delayed, so much so that James dean went out and bought a Porsche instead, rather than wait.

Post by **Peter.N.** » 25 Jul 2005, 16:21

I didn't say that drum brakes were better, I said they needed less effort to work as was demonstrated on the early Humber Super Snipe which had a 4 litre engine and weighed abot 2 tons! if fact of course none of the early lorries had power assistance and they still managed to stop until they got hot! as Jeremy noted. My first citroen was a 1980 CX Safari, discs all round, fantastic brakes. On Kowalski's point I was considering the overall weight including steel calipers, but maybe he is right.

ItDontGo · Post by **ItDontGo** » 25 Jul 2005, 22:33

The advantage of drum brakes is also a disadvantage. If you have a look at the arrangment of the shoes you will see they produce a moment about the point they stop against when they are applied. This effectively amplifies the force applied to the brake material. However this increases hysterisis (which is the one-wayness to get all technical on you) of the brakes and hence are tricky at the point where the brakes lock because you have to come off the brakes a lot to reduce the braking force. This is good for being a handbrake though ofcoure however anyone who has ever owned a Fiesta will know that the handbrakes do not work in reverse because the moment, in this case, acts in the opposite direction thus reducing braking force.
Disc brakes do need a great force to operate them. If you ever disconnect the vacuum pipe on even a light car like an AX you really appreciate how hard the pedal needs to be pushed. I have been priveledged enough to have driven a wide range of single seater racing cars which only weigh about 400kg. Even though they are so light they always need a relatively massive amount of pressure to be applied to the brake pedal to get the most out of them.

oscarloco · Post by **oscarloco** » 26 Jul 2005, 05:30

I drove a relatively low weight car (Honda Civic Sedan GL) without power assitance to the brakes. One day while rallying, a big rock with enormous attractive force pulled my car's radiator toward it and BAM! I had to be towed by one of the judges for about 120 km. During that time I had to use only my right leg power for braking and indeed, I required a lot of effort even tough it had drums in the rear.

Post by **RichardW** » 26 Jul 2005, 13:42

Our 82 Visa Special (the 602cc one!) had no servo on the brakes. It required a hefty shove on the pedal to get it to stop - if you locked the wheels you knew you were probably going to be in trouble! It teaches you a lot about anticipation when you have a car that takes an age to wind up, and then when you get it there, won't stop! None of these namby pamby driving 'aids' current learner drivers seem to get - like an effective heater for instance [:o)]
Still, the car was great fun, and if I saw one for sale without too much tin worm, I'd probably have to buy it!

jeremy · Post by **jeremy** » 26 Jul 2005, 21:00

Learners - heater - its air con or climate control now - but just think of the poor instructor - he's probably spending as much time in the little car as he is at home!
jeremy

rossnunn · Post by **rossnunn** » 26 Jul 2005, 21:38

I've never been a durm fan, me & drums never seem to see eye to eye.