Alternative to locking diff...brake lock diff

[Anton2k3]

I've just stumbled across this by accident. Apparently some jeeps are fitted with this brake lock diff system. Essentially, the system will apply the brakes (as much as necessary) on the spinning wheel to allow the power to transfer to the other (hopefully over some better ground) wheel to turn. Its not a real locking diff obviously, but would be enough to get out of many situations. So, here is the question, how to apply this system, to another vehicle which doesn't have it?

On my Mercedes Vario, I have an air hand brake. In theory, the system could be plumbed to control two individual progressive solenoid valves. However, the control part is a little more tricky. Maybe something like an encoder and encoder wheel to the hub to measure wheel rotation? And a great programmer to write some code to make it all work. Who's volunteering? I'm sure an arduino or similar could be used for this.

Any input?

something like this for the encoder http://www.megamanual.com/ms2/wheel.htm

 

[LocoCoyote]

What you are describing is basically what most of the "traction control" systems out there are doing anyway..... i.e. applying the brake to wheels without traction.

 

[thebigblue]

I remember reading someone had split the normal manual wire-driven single-brake-lever into a individual brake-lever for each of the two drive-wheels on a 2wd, should be fairly easy.

 

[Anton2k3]

Yea my next option was to buy a second hand brake lever/valve, and plumb them in individually. However, if it can be made to be automatic, and turned on with a switch when required, that would be even better!

LocoCoyote, yea I thought that. Have tried to find universal kits for TC but nothing has come up. Thought if we could collaborate and design something for air driven systems (hand brakes), would be useful for others. I know there are a few with wagons who want diff locks but are not commercially available.

 

[Retired Tanker]

I got a rental car (Jeep Cherokee) high-centered in snow in Wyoming a couple of years ago. There was no traction on any of the wheels. I was amazed at how the traction control would apply brakes and the wheels would spin in a pattern. First both front wheels, then only one, then the other, then both back wheels, etc.

As it turns out, nothing worked, so I jacked up the car while a buddy went and found some boards to put under the wheels.

I would think that it wouldn't be TOO hard to do, but I'm sure the system relied on the wheel encoders for the anti-lock brake system. Adding all of the processing and plumbing would be hard enough on a car with ABS, let alone having to install wheel encoders (that are environmentally sealed, etc) to a car w/o ABS.

 

[As Scooter]

I remember reading someone had split the normal manual wire-driven single-brake-lever into a individual brake-lever for each of the two drive-wheels on a 2wd, should be fairly easy.

Sounds like the old dune buggy steering brakes. It was hooked into the hydraulics. Push it forward and it would apply one side, pull it back it would apply the other side. Central was open, and allowed you to use the brake pedal to stop.
No doubt it is easily adaptable to this use.

 

[Anton2k3]

Retired Tanker, yea its not a simple solution by any means. However in reality, it would need an encoder for each wheel/hub, wires to an Arduino (or similar control unit), which controls two electric air solenoid valves...not all that much kit. The control of braking could be via opening and closing the valve at a rate proportionate to the wheel spin. A programming/algorithm issue..not my strong point! I'd love to create such a system if others are interested.

If no interest, and probably for now, i'll split the handbrake.

 

[mizedog]

I agree that this is traction control. My F150 does similar. My 2008 Wrangler went further stock than I would have predicted, but using the brakes to stop a spinning wheel is a waste of resources like time, energy, and puts the vehicle at risk as it is, waiting for inertia to gain, then spending effort to stop it. My old CJ 7 with 4 Detroit lockers was entirely different in trail situations. It was so relaxed, and I barely needed throttle.
Traction control-great for icy roads.
Real lockers- more appropriate on the trail.

Sent from my SAMSUNG-SM-N900A using Tapatalk

 

[Anton2k3]

A difflock would be great, but one cannot be retrofitted to my wagon, so this was a 'next best thing' kind of alternative. I won't be doing any trails with my camper, not while its 2wd configuration at least.

 

[ianc]

Anton,
Does your Vario have ABS?

 

[762X39]

I remember reading someone had split the normal manual wire-driven single-brake-lever into a individual brake-lever for each of the two drive-wheels on a 2wd, should be fairly easy.

We did this on a Lada Niva about 10 or so years ago, it worked great. By applying the hand brake to the rear wheel w/o traction, theoretically the other wheel might bite and restore forward motion.

 

[Anton2k3]

Ianc, unfortunately not, but I could get an ABS axle from another vario i'm sure.

762X39, that's great to hear. There may be mileage in this idea after all...excuse the pun.

 

[LukeH]

Cheaper and more reliable would be fiddle brakes as mentioned previously.
http://www.milneroffroadracing.co.uk/fiddle brakes.htm
Remember if you lock up the wheel that is slipping you're forcing the other wheel to go twice as fast, because of the open diff.
In terms of loading that means you have to double the torque coming out of the gearbox, and you're dragging an inert wheel through the mud while it's locked up. If you don't have a crawler gear that's probably a lot of clutch work which is never nice.

Quite clear, you need my 4x4 conversion.
Now all I have to do is develop it

 

[ianc]

They are still selling the "proper" 4x4 Varios at the Irish ESB auctions.....
€3,800 for the last one I saw (I was buying a Land Rover Defender - but don't tell anyone)

 

[LukeH]

They are still selling the "proper" 4x4 Varios at the Irish ESB auctions.....
€3,800 for the last one I saw (I was buying a Land Rover Defender - but don't tell anyone)

Very interesting!
Please link to the results of the last one, and the auction house.
Thanks