drums vs discs...

In many cases it is simply a matter of they are cheaper because the design and tooling was paid for long ago, and it is a point of distinction for a cheaper versus more expensive model. And there is rarely much real advantage to rear discs. The discs may actually be more expensive to make, as the caliper is probably more expensive to make than the equivalent in drum brakes (cylinders plus pressed backing plate), and there is more machining on a disc than a drum. But for many cars the reason is simply that it is easier to make a handbrake work on drums rather than discs. Although interestingly the first mass market car fitted with discs (Citroen DS) had drums at the rear but the handbrake worked on the front discs. JD

And you wouldn't expect Citroen to do anything strange after all!

It always makes me wonder when i see a new car with drums on.

Saabs have had disc brakes all round since 1969. The handbrake also worked using the front disc calipers for the majority of that time (though for a while it operated a drum type handbrake inside the hub of the disc!)

If its been possible to do it since then, how do they still justify drums?

It could be that sometimes drums are all that is required. By that I mean that the back axle does not want to be over-braked or it will/can skid under heavy braking. Since something like 70% of the brake force comes from the front then the rears may be over-braked with discs, meaning a compensator valve is needed (as per Discovery I) which adds the cost.

Just my 2p's worth.

Richard

I think you are right, but since it is easy to build discs with less braking effect (e.g. smaller diameter cylinders) the drums must be cheaper to make, as I suggested above.

As I said, Citroen had the handbrake working on the front discs since 1955 (initially with a separate caliper, but later operating the same caliper) - but they still used drums at the back - with the shoes only half lined, which suggests how little braking effort was needed there! JD

I'd go with that, especially on commercials such as Vans, Pickups and flat beds. I've had a few twitchy moments in empty vans and pickups. They would have been very very twitchy with disks on the back.

Lee

Doesn't matter what type of brakes they are, if they are set up incorrectly they will not work properly. I have a Daily with discs all round, and it is never a problem.

Saabs were known for problems with the read discs due to under use, i.e. seized callipers, rusty discs.

The vans' I've driven are probably driven with a bit more "purpose" ;-) . I'm hard pushed to actually think of any of the "firms" commercials which have disk brakes... yet to scrabble under a Sprinter as I've been driving a desk unless deployed on a mission since we supposedly "progressed" from the V8 Convoy's. Now how the hell is a Diesel supposed to compare with a V8 when cruising the town centre on a Friday night.

Lee

V8 Convoy, 144HP at 5,000RPM

The figures say it all!

Numbers numbers numbers.... give me burbble any day. I know which chorus strikes fear in to the hearts of a maurauding crowd and It's not the alternative to veggie oil ;-)

Lee

I had a 1989 Volvo 240 estate until recently, which I drove every day. When I took it for it's last MoT, the garage assumed I must have left it standing all year, both rear discs were so rusty, and the calipers completely seized. The (front) brakes had been more than adequate for several months.

-- Olly R Now with a 1997 110 Tdi Station Wagon

I had a Nissan Primera Estate 2.0L twin cam with rear disc brakes and the calipers siezed, same reason. If Nissan replace the same and pads etc it is £450 per side. So Imo the guy who started this thread should be happy the Nissan Navara doesn't have them. I certainly happy my TD4 doesn't.

Richard

My bicycle is fitted with drum brakes, now you would not want your landie fitted with caliper brakes would you :)

The reason why they have them on the Navarra is that they are made of two cars. Nissan take the front end of Nissan pickup (modern TD engine, IFS, disk brakes etc) and weld it to the back end of a Series II land rover (part-time 4WD, rusty cart springs, mud-filled drum brakes etc) and you end of with a jap pick-up!

Mine is, Defender 110 300TDi, caliper brakes all round, working on the discs!

I'm just glad it doesn't have Sturmey-Archer three-speed hubs and a twist grip gear change, like my old Grifter...

I meant acting on the wheel rims.

worse still wooden blocks operated by a lever like the old farm carts.

Yes I had guessed that...

How about rust holes in the floor, and a pair of hob-nailed boots?