Adding a case drain to excavator

[ALittleDirtWontHurt]

I need to add a case drain to a Kubota KX080 excavator to run a mulching head. Rather than pay the local dealer too much money, I'm giving it a go myself. The reservoir tank is steel so I'm assuming I'll have to cut a hole and weld a fitting. Anyone with any experience in doing this?

[firemanmike69]

Do it all the time at work your on the right track. I usually try to find a plate at the top of the tank I can remove to drill so I don't get the oil full of metal shavings then weld a fitting in then weld a piece of angle iron to the bottom to diffuse the returning oil so it doesn't foam the oil in the tank

[ALittleDirtWontHurt]

It looks like I have two access caps on top of the tank to refill with oil. I'm thinking I could utilize one of them by removing the filler cap and installing the fitting there. This way I could just use a separate piece of steel and install the fitting on it off the machine to minimize contamination and then weld it onto the tank. Could I then connect a tube to the backside of the fitting that would extend down into the oil as to eliminate foaming?

[firemanmike69]

I have never done it that way but i think you could do it that way

[TCJatko]

You might not want to submerge the return into the tank. It might be possible to have a condition where a siphon could occur.

[mrmikey]

That would work fine, as long as it exits below the oil so as not to aeriate it. Be sure to use a big enough line so there's no back pressure on the motor.

It might be possible to have a condition where a siphon could occur.

Don't think that would be a concern unless you have an external leak at the cuttinghead, if there was a leak there, you'd spot it when the rig was running.....Mike

[ALittleDirtWontHurt]

What kind of filter is needed?

[firemanmike69]

What kind of filter is needed?

You don't need a filter on the case drain line, all it does is allow oil that had leaked out of the HUD motor to return to the tank to avoid pressurizing the case of the motor causing it to crack

[tonyoz]

Littledirt, the casedrain is there to lubricate and cool the hydraulic motor. The most efficent way or dealing with the oil is to return to tank via the oilcooler. This is easily done by fitting a T into a line near the cooler. Fitting a filter is always a good idea cause if the hyd motor fails most of the debrie comes through the casedrain and may save the rest of your machine from serious damage.

[firemanmike69]

Littledirt, the casedrain is there to lubricate and cool the hydraulic motor. The most efficent way or dealing with the oil is to return to tank via the oilcooler. This is easily done by fitting a T into a line near the cooler. Fitting a filter is always a good idea cause if the hyd motor fails most of the debrie comes through the casedrain and may save the rest of your machine from serious damage.

If you go this route, which I would personally not recommend, you need to ensure that the case drain line pressure is below the factory spec at working flow and pressure. You will need a pressure gauge t'ed into the case drain and a flow meter hooked to the hydraulic outlets on the excavator, you will also need to monitor the pressure as the filter clogs