Drum Brakes; are there any advantages?

[Steffan]

Mr2Mike said:

rsv gone! said:

To those complaining about the rear handbrakes on their 4-disk cars, are you sure the handbrake is actually operating on the rear calipers? My EVO has a poor handbrake (I always leave it in gear) but the rear disk has a drum setup inside it, purely for the handbrake.

To be fair, that is a relatively uncommon set up compared to calipers with the handbrake function built in.

Primarily on cost grounds I think. Disc rear handbrakes are not the best but allow decent main brakes at a relatively low cost. Accountants yule OK! Well on most manufacturing cost decisions they do today!

[Pan Pan]

Probably already been mentioned but, heat build up in drum brakes during hard use allows brake fade to creep in, where fluids present in the shoes is boil off / is expelled when the shoes reach high temperature which forms a microscopic film of vapour between the drum, and the shoe, at which point the brakes do not work anymore. They tried to counter this by having huge diameter / d finned drum brakes, but drums where never that good compared to discs.
Having experienced this in a mates (well loaded) drum braked Morris Minor coming down the long hill into Dover many years ago, I can confirm it is terminally scary (especially going around the then roundabouts at God knows what speed, on two wheels with a car load of people all sort of screaming they were going to die at the tops of the voices, and my mate who was a great big bloke out of the seat standing on the brake pedal to try and stop the B*gger! Amazingly after they cooled down the brakes recovered to normal, but I suspect there may have been an element of the brake fluid reaching its boiling point in that event too.
I still think tiny rear drum brakes visible through enormous diameter low profile alloys looks a bit naff, painted or not.

[Pan Pan]

They crazy thing is many later generation relatively low end vehicles from the far east etc get rear discs as standard, but many European manufacturers still seem to fit drums to their low end models reduce costs. They probably do the job OK but do smack of the accountants / penny pinchers getting their way over the specs.

[LuS1fer]

Mr2Mike said:

rsv gone! said:

To those complaining about the rear handbrakes on their 4-disk cars, are you sure the handbrake is actually operating on the rear calipers? My EVO has a poor handbrake (I always leave it in gear) but the rear disk has a drum setup inside it, purely for the handbrake.

To be fair, that is a relatively uncommon set up compared to calipers with the handbrake function built in.

Used on the 4th gen Camaro too but being inside the hub, the shoes were small so not great.

In my view, the rear discs don't do a lot so tend to corrode more - many rear discs you see seem to lack friction on some of the disc - the humble drum brake at least afforded the shoes a some shelter from the rain and stayed dry on pad and braking surface. I cannot recall thinking the rear braking was any better on any rear disc-braked car.

Shoes were also easier and quicker to replace with a suitable pair of spring pliers.

[TallPaul]

LuS1fer said:

Shoes were also easier and quicker to replace with a suitable pair of spring pliers.

Until a lip had formed/corroded onto the inner edge of the drum and the manual adjusters had seized, then getting the drum off could be a "challenge"!

[MG CHRIS]

rsv gone! said:

Mr2Mike said:

I've never seen a brake disc with the reluctor ring built in, they are normally built into the hub.

This.


To those complaining about the rear handbrakes on their 4-disk cars, are you sure the handbrake is actually operating on the rear calipers? My EVO has a poor handbrake (I always leave it in gear) but the rear disk has a drum setup inside it, purely for the handbrake.

Edited by rsv gone! on Tuesday 14th January 06:10

Renault use it reluctor ring on the back of the discs but the bearing is built into the disc aswel. A few other manufactures do it aswel.

[Mave]

LuS1fer said:

Mr2Mike said:

rsv gone! said:

To those complaining about the rear handbrakes on their 4-disk cars, are you sure the handbrake is actually operating on the rear calipers? My EVO has a poor handbrake (I always leave it in gear) but the rear disk has a drum setup inside it, purely for the handbrake.

To be fair, that is a relatively uncommon set up compared to calipers with the handbrake function built in.

Used on the 4th gen Camaro too but being inside the hub, the shoes were small so not great.

In my view, the rear discs don't do a lot so tend to corrode more - many rear discs you see seem to lack friction on some of the disc - the humble drum brake at least afforded the shoes a some shelter from the rain and stayed dry on pad and braking surface. I cannot recall thinking the rear braking was any better on any rear disc-braked car.

Shoes were also easier and quicker to replace with a suitable pair of spring pliers.

Don't know which models did / didn't have this set up - but it was certainly on my 3 series, and on my wife's Saab 900. I think on my A6 also; so not totally unknown.