Drive Shaft Drum Brake

[pbroz]

Can anyone enlighten me why or what the history was on the drive shaft mounted drum hand brake on the defender / series vehicles. Is it a hand over or legacy from PTO output days? Is there any reason why they are still maintained today on the Puma's? :bangin:

[roverrescue]

Because they work... sometimes simple is not only simple but is also the best.
Have you ever worked on tojo POS drum in rear disk brake junk? For example...

Steve

[Blknight.aus]

it was initially done to simplify the brake setup on the rear axle and prevent accidental wheel lockup by fouling of the parkbrake mechanism (usually a cable) while off roading. It has the added of advantages of

it uses the reduction ratio of the Diff to increase the braking effort so a smaller brake can hold the weight of the vehicle.

with a completely seperate braking mechanism contamination of the service brake shoes/drum from mud/oil/grease/water still leaves you with a working brake mechanism.

it can be used to lock the diff in position to aid in the removal of broken axle bits

it can act of both axles or just the rear depending on how you set the CDL. this is also true of the handbrake in the rear wheels setup untill you snap a rear axle.

with the CDL open you can use it to add some tail end only drag on a descent while you provide drive to the front end to pull the nose down hill (which you can also do with the handbrake in the wheels) but the rear diff will still alow the rear wheels to turn normally (which you cant)

it allows you to lock the Tcase up so you can undo the output drive flange nut.

It allows you to lock the propshaft while you undo the propshaft nuts (if you need to)

once removed it provides a handy, usually easily cleaned, place to put the bits from in the Tcase while you do a field fix.

[pc3]

So basically the Defender Hand/Park Brake is a better system than Toyotas ?? Yet it seems to cause issues in PUMAS ??

[Tombie]

Its also standard on Patrols...

[Tombie]

So basically the Defender Hand/Park Brake is a better system than Toyotas ?? Yet it seems to cause issues in PUMAS ??

Pumas suffer lots of problems from the "Rushed engineering" in my opinion...

One difference is the gearbox etc positions the drum in a worse location!

[JDNSW]

While Dave's points are all valid, you need to go back and look at where it originated. The transmission handbrake on the Landrover (and the original Landcruiser and Patrol) almost certainly were copied from the original Jeep, which in turn copied it from the Bantam design. In 1940, transmission handbrakes were pretty much normal in US manufactured vehicles, as they provided a simple, effective, mechanical system, independent of the main braking system. Hand braking on the rear wheels complicates the mechanism inside the rear brakes, and the cable operated rear brakes were notorious for not working more than a few days after being serviced. (My sister has been indoctrinated by fifty years of marriage to a mechanic husband to never use the handbrake in case it jams on - he was trained in the 1930s and his ideas fixed in the fifties and sixties)

Landrover has retained the system because it is effective, simple and well tested. It has probably been dropped in the D3/4 and the latest Landcruisers to save underbody space. These vehicles are much less used offroad, so lowering the c of g and interior space are more important.

John

[BigJon]

(My sister has been indoctrinated by fifty years of marriage to a mechanic husband to never use the handbrake in case it jams on - he was trained in the 1930s and his ideas fixed in the fifties and sixties)



John

I hope her car is never struck by another vehicle when parked. If it moves after being struck she will be liable for damages as it has not been legally parked.

[harry]

if you think it is a weak thing, you are wrong,
and many prime movers have this setup
it does brake all wheels, not two like the non constant fwd things
have faith in it

[JDNSW]

I hope her car is never struck by another vehicle when parked. If it moves after being struck she will be liable for damages as it has not been legally parked.

Parked in low or reverse is only going to move by skidding all four wheels (AWD), not much different to a handbrake. She has got away with it for over fifty years of driving with zero infringements or problems, so I can't see that there is much probability of a problem (except for the possibility of gearbox damage).

John

[pbroz]

thanks everyone curiosity answered.

[BigJon]

if you think it is a weak thing, you are wrong,
and many prime movers have this setup
it does brake all wheels, not two like the non constant fwd things
have faith in it

Actually, it doesn't brake any of the wheels, much less all four, unless you have all diffs locked.

[DeeJay]

Actually, it doesn't brake any of the wheels, much less all four, unless you have all diffs locked.

Even then it won't "brake" the wheel - if you mean applying the pads.:angel: