USMC M813 fording question

[dilligaf13]

I've got a USMC M813, with the fording kit, that I bobbed for a full time trail truck. My question is the axles don't have the air lines, for low air pressure. There are three lines running off the fording kit. The first is in place and runs to the bell housing. The second runs to the air horn. The third is the problem. It runs down the passenger's side of the engine block and ends. Where is it supposed to go? Thanks.

 

[Floridianson]

That would be the road draft tube and when fording it is closed off when you pull the fording leaver.
That's why we have to watch long fording or returning the valve to the open position after fording because of the crankcase pressures.

 

[dilligaf13]

Gotcha. So do the axles do not receive positive pressure from the crankcase, when the fording lever is pulled? For now I just ran some hose from the axle vents up into the cab to ensure they don't suck in water. It also looks like top of the master cylinder has a 90 degree NPT elbow so I'll just run a secondary brake reservoir, up in the cab, to overcome this issue. The transmission has 3 lines running off the top but I don't see a vent, like the deuces have. Is there anything up there that needs to be plumbed higher? Thanks.

 

[73m819]

Those trans lines go to the transfer case for shifting the sprag.

 

[Floridianson]

About the poppets on the trans. one would think since it is just a exit for the air when the piston changes from forward and reverse it should expel what little water could get in there. Since there is a fitting with NPT threads for the exhaust fitting it would be easy to do. Also I would since your there tighten all 8 of the bolts that hold the poppets together and to the trans. as I always find them loose when I check the trucks that I am servicing.

 

[Floridianson]

Also I would worry about the fuel tanks. The ones I have seen have non vented caps and you better make sure the gasket does not leak. Also most of the vents I have seen on the fuel tanks have a fitting then rubber hose and plastic lines that run to the vent block that is on the passenger side of the engine firewall. I just did one where I unscrewed the fittings out of the fuel tanks and replaced with barb fittings from NAPA and one brass T fitting to join them together. Then ran new rubber line to the engine bay block and a barb fitting there.

PS the best laid plan of mice and men. I hate fording as no matter how I prepare the truck water wins out somewhere, somehow. I will say always carry a extra fuel filter and a big wrench so you can drain the water out of the fuel tank and replace the fuel filter. The front axle can be checked buy taking out one of the four lower bolts that hold the spindle caps on. As for the bell housing just get a ball valve and screw it into the hole and you can open and close without a wrench. Also the power steering pump has to be vented and water tight.
Like the movie JAWS don't go in the water.

 

[dilligaf13]

I relocated the fuel tank for that exact reason. I like the idea of the ball valve on the bell housing that's way easier than placing/pulling the drain plug, especially when the underside is dripping water and mud all over you...

Definitely need to pickup a couple spare fuel filters.

 

[dilligaf13]

Another question. Does the vent tube, on the top of the airpack, need to be routed above the water line for fording operations?