How does the m1078 4x4 work?

[Ronmar]

but could it be adapted to ONLY front brakes for those whom have a locker in the rear?

Yes. My design is modular, one module per wheel and some interconnecting wires for sense and power so you will be able to do it for any axle desired...

 

[1stDeuce]

Good luck "bleeding" the parking brake... It's a spring, not air pressure that applies the parking brakes.

What you need is to keep air from getting to the stopped wheels so you can apply the foot brake till you're moving... Or till the stopped wheels spin, and you're still stuck. That way you can modulate the pressure and release it when the truck starts to move.

The slightly scary part is that if you had a failure in the system that locked out all four brakes, you have no brakes, but so long as you're using air solenoids that are normally open, most failures of the electrical system would result in normal brake operation.

To go one step further, it's normal for the opposite tires to spin, so if you cross linked the brake lockout solenoids, you'd get twice the traction transfer.

Now go make it happen!!

 

[Ronmar]

Good luck "bleeding" the parking brake... It's a spring, not air pressure that applies the parking brakes.

yes, but if you bleed the air off of a particular side’s parking brake can, it will apply the park brake spring on that side...

my idea does not block any braking air, and having to apply the brake pedal while trying to apply the gas pedal can be problematic.

My idea adds brake air to the can on the wheel that is spinning. Since it only works, and only has access to air with power applied a flip of the switch will disable it. It can also at any time be overridden by the brake pedal...

 

[ppillard]

Bleed the parking brake on the spinning tire(s)...? That's what I'd like to play with someday....

You just described how modern Toyota automotive traction control works.

 

[doghead]

 

[1stDeuce]

yes, but if you bleed the air off of a particular side’s parking brake can, it will apply the park brake spring on that side...

my idea does not block any braking air, and having to apply the brake pedal while trying to apply the gas pedal can be problematic.

My idea adds brake air to the can on the wheel that is spinning. Since it only works, and only has access to air with power applied a flip of the switch will disable it. It can also at any time be overridden by the brake pedal...

Ok, I see what you're saying, but now you only have it working on the rear axle, and it seems like it would be difficult to modulate the bleed off and re-apply pressure with valving. Using the brake pedal to apply pressure like it's supposed to seems easier to me, but it would certainly accomplish the same thing.

Gas and brake at the same time is not at all problematic, I do it all the time in my Jeep with TrueTrac differentials. Two pedals, two feet. You have to do the same thing when climbing ramps, or moving a very controlled small distance. Same thing here.

Either way, it sounds like you know that the park brake is spring applied, and pressure release is what engages it. I was concerned that you thought bleeding off air would release the parking brake, which is not how it works.

Do post up how your project works out if you do it!!

 

[Ronmar]

This system will apply service air and can be fit to any axle. It wont mess with the park air system at all, as there are no park brakes on the front axle, and having the front axle being able to apply max traction is pretty desirable IMO. It will respond as fast as the solenoids can apply air and since they are right down near the wheel cans, it should respond a little faster than the pedal does supplying air from the treadle valve in the cab...