Cutting brakes

[feerocknok]

 

Has anyone thought about taking advantage of the two back lines being seperated, and making cutting brakes?

 

In case you don't know what they are, they use em in sand rails, and it's a brake that'll just lock up one tire, to turn sharper. They also use em in dirt track cars, but the system's way complex for those.

 

I had talked with some people before about using it like a locker with an open diff.

When your back left tire is in the air, an open diff will transfer all power to that tire, meaning the truck has no forward motion. Applying the back left tire's brake, the back right tire now has the ability to move!

[Eagle]

Pretty much all cars and PUs have separate cables to the two rear wheels. Converting that to fully independent cutting brakes requires adding two levers inside the cab and separate forward cables. It can be done, but for probably 98% of MJ owners wouldn't provide any benefit.

 

The same thing can be accomplish hydraulically, using a pair of drag racing line locks.

[DirtyComanche]

Would you actually be able to put enough force on the brakes with the ebrake to actually give you any real traction benefit?

 

 

 

Besides, it's not always as simple as having a tire in the air. Winter wheeling is an example...

[Eagle]

Would you actually be able to put enough force on the brakes with the ebrake to actually give you any real traction benefit?

 

 

 

Besides, it's not always as simple as having a tire in the air. Winter wheeling is an example...

Yeah, you can if you have good rear brakes and keep them adjusted. But a hydraulic solution provides more braking power, for sure.

[feerocknok]

How do the hydraulics work?

[87manche]

line locks are solenoids that trap the brake fluid in the cylinder under pressure.

So you ould put two line locks on the hards lines going to each wheel cylinder, and you;d have two switches in the cab. Step on the brakes, hit a switch and you lock the wheel that corresponds to that switch.

http://www.rpmoutlet.com/hurst.htm

[Eagle]

Yepp, that's how you'd use line locks. Or you could set up a pair of levers running small hydraulic cylinders either in the cab or under the cab floor and run those through independent lines to each rear wheel. The catch is, though, that the rear wheels can't be hydraulically connected or applying pressure to one will apply pressure to both. So you would basically have to eliminate normal rear brakes, and have only the hydraulic cutting brakes. (Or you'd have to install a sophisticated system of one-way check valves ... it can be done, but at what point do you say "This isn't worth what's it's costing"?)

 

IMHO cutting brakes are a very specialized application that have no place on a vehicle that gets driven on the street. If you have a trailer queen that sees a lot of use in sand, then maybe there's some justification for them.

[Oizarod115]

ive thought about that open diff use before.. especially after using the brake-trick to get the truck to move a little when stuck with open diffs.

[jeepmj_tj]

why not just put in a cherokee hand brake, and have the mj foot pedal control only the driver rear tire and the xj hand brake control the right rear.

[Bounty Hunter]

With an open diff, you would likely have to lock the spinning tire completely in order to gain any forward momentum from the opposite tire.

 

Now a limited slip differential would do what you're suggesting very well as it only takes a little brake bias to transfer torque to the opposite tire.

[pingpong]

Also cutting brakes are designed for rigs that can do front, or rear digs only. The advantages are minimal at best. Brake biasing is an easier form of what you are talking about and works just as well, but it doesnt require mods as much. It just involves applying the brakes as you are giving it gas.