Case 446 valve

[Kirk-Tx]

Can someone explain or post a diagram of how to plumb a valve that controls a tiller on a 446 case garden tractor? The tiller has quick connect connections. I'm not sure where to run lines back to pump. Thanks
 

[Tom Arnold]

You are referring to the hydraulic PTO valve mounted on a bracket just behind the Operator's seat.

If you look at that valve where the lines enter the sides, you should see the words IN and OUT. Begin by installing the bracket/valve unit to the tractor but do not tighten the bolts down. You want the valve to be flexible at this point. Remove the mower deck and jack the tractor in the air and use jack stands to support this 800 LB machine.

If you slide underneath with a trouble lamp, you will find the Travel/Lift valve under the checker plate floor. You will see a hose coming from the output of the pump to the IN side of that valve. After draining the hydraulic oil out of the reservoir, you need to remove that hose from the fitting on that valve.

The line coming from the IN port of the PTO valve gets connected to that hose. The line coming from the OUT port of the PTO valve gets connected to the fitting on the IN port of the travel valve. Once you have both ends of each line mostly screwed onto their respective fittings, you can now tighten the valve bracket solidly to the tractor. Then, tighten all lines to the fittings. Do not use any sort of thread sealer or teflon tape. It is not needed nor wanted.

On the bottom of the travel valve, there is a hex shaped pipe plug. Clean the hex hole out thoroughly and then use either a new or very good Allen wrench to crack that plug loose. You only get one shot at this because if your Allen key is junk or not inserted 100 percent, it may spin and ruin the pipe plug.

With a clean bucket under the valve, remove the pipe plug. Start the engine and the fluid will pump out into the bucket. When you see spurting, shut down the engine. If you have been careful to keep the oil clean, you can reuse it. If the oil is more than two years old, then replace it with fresh 15W40 motor oil or 20W50 motor oil. If you have a tractor with the tank under the battery, then fill that tank to six inches below the top of the filler neck.

If you have a tractor with the front mounted tank, then fill that one to an inch and a half below the actual top of the tank. This is to allow for oil expansion.

Any questions?
 

[Kirk-Tx]

Let me check it out in a couple of days, and I'll get back with you. Thank you
 

[Kirk-Tx]

Thanks Tom. After re-reading your post, that makes perfect sense. I assume the valve lets the fluid bypass continuously to run the other functions. In my part of the country, it's time to have garden plowed, onions planted and a few other things in the ground. This tiller that we bought will make it much easier.
 

[Tom Arnold]

These tractors use what is known as an "open center system". The oil flows from the pump to the PTO valve, to the Travel/Lift valve, to the oil cooler and back to the reservoir, ready for another trip through the pump. The lever on the PTO simply diverts 100 percent of the oil flow to whatever attachment is connected to the valve.

Either way, all of the oil flow ends up leaving the PTO valve and going to the Travel/Lift valve where a portion can be used to raise or lower attachments and either all of the flow can be sent to the drive motor or just a portion.

The oil is in constant circulation, ready to go to work for you at the flick of a control lever.

When you first connect up that tiller, remove one quick coupler on the tiller and stick the hose into a bucket. Then with the engine idling, open the PTO valve and flush out the tiller motor and lines. For the cost of a quart of oil, it isn't worth risking contamination to your system.

While the tiller will rotate in both directions, the tines are only sharpened on one side. If you are tilling hard ground, then the rotation direction is going to matter.

Even the PTO kit should be flushed out prior to installation for the same reason. The lines or hoses can be cleansed with solvent or with fresh diesel fuel. There is so little oil in the valve itself, it isn't worth bothering with if the ports look clean inside.