Anybody recognise this free wheeling hub

[diffwhine]

These freewheeling hubs are fitted to a 109 I'm looking at in South Africa. I've seen them before, but don't know who makes them or how they work. Does anybody know anything about them ? Are they auto hubs?

They are fitted to a vehicle I may be buying and bringing back here. I don't like FWHs, but if they are original, I may leave them on, but could do with understanding how they work.

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[Twomokes]

There are MAP  auto FWHs

[autorover1]

The MAP auto version uses a cam & roller inside to give drive to the wheel but the wheel cannot drive the shaft , only the shaft the wheel. As such it was never approved by Land Rover as you get no engine braking on overrun through the front wheels  . A bit like the original 80" , with a freewheel, but that had a lock facility 

[diffwhine]

Thank you all. Confirms my thinking. I'm guessing that like an early 80", that ain't great in reverse on a failed hill start in mud then... I wonder if they tend to lock up in reverse?

They are fitted to a 109 Dormobile and if I do buy it, I want to preserve its originality. I think though, that these will have to go.

[Craig T]

109" Station Wagon Dormobile? What year?

I realised last weekend I was driving around with my MAP selectable hubs in the engaged position. Never noticed....

Craig.

[autorover1]

Thank you all. Confirms my thinking. I'm guessing that like an early 80", that ain't great in reverse on a failed hill start in mud then... I wonder if they tend to lock up in reverse?

They are fitted to a 109 Dormobile and if I do buy it, I want to preserve its originality. I think though, that these will have to go.

They work ( lock up) in both forward and reverse direction , but the wheel wont drive the shaft , so its the loss of engine braking that is the issue, such as down a steep slope .
A farming friend of mine had them on a 2A forward control with Rover axles . Before fitting he  kept breaking rear diffs/half shaft. and they solved the problem by always driving through both axles and he didn't have to mess about locking & unlocking manual ones going from loose to hard surfaces.  Of course Rover solved the problem by fitting ENV diffs on the 2B & offering a retrofit for the 2A

[GlenAnderson]

I have a single one of them in my stores. If you decide to keep them fitted and want a spare, drop me a line. Likewise, if you choose to remove them, let me know as I'd be interested in taking them off your hands.

[Exile]

They are ideal for Station Wagons (and camper types) which do not do hard offroading and seldom need the engine braking on steep downhill slopes.

These vehicles tend to be mostly used on roads, on slippery grass on campsites, in snowy conditions and the like.

The auto hubs give traction when you need it, but don't give 4WD when you don't.


To understand them, think of brake shoes in a brake drum, except that these shoes are small and metallic and are held off the "drum" by little springs.


When the rear wheels are spinning and slipping and 4WD is engaged, the front halfshafts are spinning faster than the disconnected front wheels.

Centrifugal force spins the "shoes" outwards to bind on the "drum" and transmit drive to the wheel.



On over-run, such as going downhill the wheels are being turned by gravity and not the halfshafts, and will want to throw the "shoes" off the "drum"  (aided by the return springs).


That is how I understand it, but others may have a better description.
 

In common with many other Station Wagons, my 109" which was used by the previous owner for long trips to Switzerland towing a caravan, came to me with MAP Auto Hubs fitted.

[diffwhine]

109" Station Wagon Dormobile? What year?

I realised last weekend I was driving around with my MAP selectable hubs in the engaged position. Never noticed....

Craig.

It was registered in South Africa as new in December 1964.

I take the point that Exile makes about applicability for this type of vehicle and usage. Maybe Dormobile fitted them as standard then. Perhaps I should leave well alone if this project actually comes off!

[Genocache]

  So in the event you are on a slope and a rear halfshaft breaks, the transmission brake has no effect?

[autorover1]

I had forgotten that potential issue  !

[Exile]

I seem to be a bit of a collector of boxes!

I suspect the box for the Automatic hubs is rarer than the hubs themselves!

[Craig T]

Wow, nice boxes.... 

Interesting to see the red paint around the letters on the manual versions. If that was original, I might have to get my tin if red Humbrol out....

Craig.

[Exile]

So in the event you are on a slope and a rear halfshaft breaks, the transmission brake has no effect?

If your rear half shaft breaks on a slope, keep in 4WD and keep revving the engine.

The front halfshafts will spin and engage the automatic hubs.

Drive to a safe place.

 

You cannot do that with fixed FWH, in the unlocked position.

[s2c-08616]

Seems there are folk who like freewheeling hubs. And those who don't!  I'm thinking go going down that route. But then, I'm going to drive a couple of thousand miles a year. Advice please!