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.:2cents:

 

[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.:2cents:

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

 

[SSdoxie]

Case drain line needs to have minimum back pressure possible. It is fine to run it through the oil cooler if cooler has no pressure drop acorss it, or less than 5 psi. Case drain should also have a filter in case of motor bearing failure or internal motor failure, to keep the debris from dumping into the reservoir and contaminating the entire hydraulic system. Northern Tool (among others) has 10 micron return fitlers for about $25 which will handle upto 20 GPM. Case drain line normally will only be running about 10% of the pump flow to the motor. So a 20 GPM pump to motor flow will only be around 2 GPM case drain flow. If you don't go through the cooler, dump it into the tank below the fuild level and make sure it is as far away from the suction outlet as possible. Dumping into the suction or close to it can cause a swirl action that could cause areation to oil going into the pump.

 

[tonyoz]

Refer to the way your PT100 is plumbed. Heat is the biggest cause of failure in mulching equipment especialy in open loop hydraulics which is what you have. At the end of the day it's your machine and your money your sending, just hope you spend it wisely and once.:thumbsup:

 

[ALittleDirtWontHurt]

Thanks for the help so far.....here's what I'm working with. Looks like that top access lid may be the way to go.

 

[nwterex]

Give Ed in our shop a call he has done a couple of 80's and he will be able to walk you through the case drain.

 

[deniscimafinc]

Or call Gilles, our tech manager (toll free 877-279-2300). Even if it's not for running one of our head, he'll help you no charge. This is our way to say thank you for your good comments on Eric H's post this past November. (Cat 297c, if you read this, don't worry, you will not be forgotten either :thumbsup: )

 

[cat 297c]

Or call Gilles, our tech manager (toll free 877-279-2300). Even if it's not for running one of our head, he'll help you no charge. This is our way to say thank you for your good comments on Eric H's post this past November. (Cat 297c, if you read this, don't worry, you will not be forgotten either :thumbsup: )

Just give me a Cimaf Generation 3 180E for my CAT 299D XHP an we'll call it even!!!!!!

 

[deniscimafinc]

Just give me a Cimaf Generation 3 180E for my CAT 299D XHP an we'll call it even!!!!!!

I'll start giving good comments on the Audi R8, if that can land one in my parkway. :laughing:

 

[cat 297c]

I'll start giving good comments on the Audi R8, if that can land one in my parkway. :laughing:

I hear ya!!!

 

[Eagleview]

As SS said , the case drain must be below the fluid level in the tank . Most lines going into the tank below the fluid level are drains , a "TEE" into one of these at the tank works well and eliminates the need for welding and drilling .

 

[ALittleDirtWontHurt]

It appears my tank is pressurized. Would this affect anything installing the line coming in through the top of the tank but returning below the fluid level?