B7800 front axle vent modification

[Muleskinner]

Through the years I have restored several military vehicles, along with several civilian Jeeps and other four wheel drive vehicles. One thing I noticed about the military vehicles was the front and rear axles, transfer case and transmission vents were always connected together and vented to the intake manifold. This was a design intended to keep water from entering the components when the vehicle was being operated in deep water. The system also keeps out dust and other foriegn matter.

I looked at the front axle on my new B7800 and was disapointed to find Kubota left the axle vent tube open to the atmosphere. This will allow dirt and water to enter the front axle. Today I modified the system to eliminate the problem before it happens.

Using 5/16" automotive fuel line hose, I attached the hose to the front axle vent and then routed the hose up to the air cleaner. I then removed the air cleaner housing, drilled a hole in the atmosphere side of the housing and epoxied a 5/16" fitting to the housing.

I then attached the fuel line hose to the fitting. After the instalation was complete, I used black plastic tie straps to attach the fuel line hose at various points to the engine so it will not come in contact with the exaust system.

I now have a closed front axle that will be vented by a slight ammount of vacuum from the engine intake. End of problem before it occurers. /forums/images/graemlins/wink.gif

 

[5030]

Muleskinner:

The reason why the vent is not hosed is simply that if you submerge the axle in water over the centerline of the hubs, you wil contaminate the gear oil anyway. The front axle on a 4wd tractor is not designed to be waterproof. You don't even have lip seals in your front end, just an O ring to keep the oil in.

 

[Muleskinner]

I live in the Southern California high desert. We get very little rain, and when it does rain, my B7800 will be inside of it's garage. I would never take it into water over the center of the axles. If you have to, that's your choice. My reason for the modification is to keep dust out of the axle.

But, if the O rings keeps the oil in, then they must be able to keep water and dirt out. An O ring is a good sealer if the machined surfaces are correct. There are a lot of O ring applications that will keep internal fluids in and water and dirt out.

If you vent the axle to the atmosphere, then you will get all of the outside contaminates in along with the air the vent tube was meant to let in. I'll take my chances with a closed system, rather than a open one.

 

[JerryG]

I think that was a good idea. You would think that they would do that at the factory sense these tractors were originally intended to work rice fields. Or at least elevate the vent.

 

[5030]

Jerry:

My 5030 is a pretty expensive rice paddy tractor!!

Actually, it isn't a bad idea, but regular oil changes in the front drive would negate any wear that the ingress of dust or dirt would cause. I would think only a minuscule amount of dirt might and I say might be drawn into the front axle case by thermal contraction of the air above the final drive oil as it cools from it's operating state to idle temperature.

From a cost prospective, it would be prohibitive for the factory to put breathers on the front axles that were hosed into the tractor body.