Oily transmission drum brake, transfer case drain mod.

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Chonker

Member
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54
When taking out my gearbox/transfer box to rebuild the gearbox I saw that the transmission drum brake was swimming in oil, presumably coming from the transfer case.

A friend of mine mentioned a common mod where a drain hole is drilled into the rear of the casing, I'm looking for more information on this please?
 
Two places the oil can come from. The flange seal itself and it has to have a good land on said flange for it to seal. And oil can come down the splines. Here a felt/rubber washer fits behind the big nut/washer.
No Mod needed. On the same bolts that hold brake backplate on is a pressed metal oil catcher [has a gasket]
At the bottom of the alloy casting behind backplate there is a slot that allows any oil that gets into the drum to escape. Make sure it is clear. It is meant to deal with small amounts, if seal gone it needs changing.
 
Ok then thanks

I have a seal kit already which includes the felt washer.

Any tips for decontaminating the brake shoes?
 
The transmission brake shoes not as important as the wheel brakes, so you can clean them up with brake cleaner and roughen with sandpaper but you might find they still work adequately even when contaminated
 
Hand brake shoes just need degreasing, hand brake must only be applied when vehicle is stationary. This to avoid transmission damage.
 
Hand brake shoes just need degreasing, hand brake must only be applied when vehicle is stationary. This to avoid transmission damage.
I've read the owners handbooks for the SI and II and there is nothing in them about using the handbrake in motion, can't find an SIII handbook, but can't see why it would be different.

A well adjusted brake on a Series is unlikely to put as much stress on the downstream transmission as the engine can, and the load on the upstream transmission is no different to a very steep hill.

There is an instruction not to for the 90/110 with permanent 4wd. That'd be because it would send the centre diff mad. I don't see it doing much harm in difflock though?
 
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I'd advise not to pull the hand brake whilst in motion on dry tarmac. It's easy to snap a rear shaft or punch the rear diff pin out through the axle casing. I'e seen this several times. Easier to do on Series 3 with the much longer hand brake lever.
 
I'd advise not to pull the hand brake whilst in motion on dry tarmac. It's easy to snap a rear shaft or punch the rear diff pin out through the axle casing. I'e seen this several times. Easier to do on Series 3 with the much longer hand brake lever.
I'm afraid I need to be convinced that any LR drum brake can produce more torque than the engine.
 
Are you good at changing half shafts?
I've removed/fitted 12, never broken one. Still got a weep from one cap on the Lightweight.

Honestly, read the owner's manuals. No mention of not using the handbrake on the move. That came in with the centre diff.

Then answer this.

Can you fully engage the handbrake and drive off in first gear, albeit with a fair bit of welly?

If so, which is more powerful, engine or brake?

And if it's engine, how can the brake do more damage to the prop, diff and half shafts than the engine?
 
I would think that any issue would be sudden change in direction of torque rotation when hand brake yanked on, perhaps made worse by any rotational play in an old diff.
 
I would think that any issue would be sudden change in direction of torque rotation when hand brake yanked on, perhaps made worse by any rotational play in an old diff.
I've downloaded an app called Dragger that's supposed to measure acceleration. I'll have a play tomorrow/Thursday but I've got a feeling that the handbrake (only needs to hold a car on a 1 in 6 slope) isn't much more effective than changing down through the gears on a petrol engine.
 
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