Purging milky oil from system

ramzee1 · Dec 28, 2011

wdchyd, Thank You for mentioning that about the air. I have a similar problem with the winch on my dozer. We've been looking for a way for the water to get in but could'nt find it. We have changed the oil a couple times an moved the breather, changed gaskets and still get milky oil. We moved the dozer in the shop and let it set two days and the oil is back to normal color, pull the drain plug and no water. Now we'll begin the task of looking for an air leak. I think we are on the right track now. Thanks, Russ :thumbsup:

wdchyd · Dec 28, 2011

ramzee1 said:
wdchyd, Thank You for mentioning that about the air. I have a similar problem with the winch on my dozer. We've been looking for a way for the water to get in but could'nt find it. We have changed the oil a couple times an moved the breather, changed gaskets and still get milky oil. We moved the dozer in the shop and let it set two days and the oil is back to normal color, pull the drain plug and no water. Now we'll begin the task of looking for an air leak. I think we are on the right track now. Thanks, Russ :thumbsup:

You'll welcome Russ,

This happens more times than you would think....The first thing I do is determine which problem it is.....

A glass jar full off coffe milkshake on a sunny window sill will tell a story.....from there it'll give you a direction.....

Like others have said here many times a suction leak will sneak up on you..... suction hoses, connections, tubing, pump shaft seal all can be culprits...

If the suction leak is in a questionable spot, then pack it with grease, start it up, to see if it keeps the oil clear from an overnight rest.......if the pump shaft seal is exposed, sometimes this is an easy way to rule out bad shaft seal.....glob it right on.....

I had a job where 2 technicians spent 3 days looking for a suction leak on a large press brake at a welding/fabricating shop...air bubbles in oil and knocking sounds.......the hyd pump was above the reservoir and was not leaking oil when it ran......so the other guys said "There's nothing wrong with the pump".......standing on top of the machine I called for a new tube of grease from my helper......2 grown men looked at me like I had 3 eyes.......I emptied a half tube of grease on my hand and smeared it on the exposed shaft coming out of the pump.....

I said "Start it up"....and the pump noise smoothed right out......took about 10 minutes to find the problem.....bad hyd pump shaft seal

If you have trouble finding the issue, grease will be your friend.....:thumbsup:

JimDD · Jan 8, 2012

I too have an older Kubota with a moisture in hydraulic/transmission fluid problem. It is a used tractor that I bought last fall to bushhog six acres. Tractor ran fine as I bushhogged twice during October and then I put it up in covered storage for the winter. All fluids were adequate levels and clean. The week before Christmas, I was down at the place and for some reason I checked fluids again and this time the hydraulic fluid was yellowish and milky. The barn is new and nothing rainwater wise leaked on the tractor. I was going to drain the fluid to replenish with new but wondered if there was something I was missing.

Dakota_male · Jan 8, 2012

JimDD said:
I too have an older Kubota with a moisture in hydraulic/transmission fluid problem. It is a used tractor that I bought last fall to bushhog six acres. Tractor ran fine as I bushhogged twice during October and then I put it up in covered storage for the winter. All fluids were adequate levels and clean. The week before Christmas, I was down at the place and for some reason I checked fluids again and this time the hydraulic fluid was yellowish and milky. The barn is new and nothing rainwater wise leaked on the tractor. I was going to drain the fluid to replenish with new but wondered if there was something I was missing.

My tractor did the same thing because I left it parked outside in the late fall for a few weeks, transmission fluid picked up a small amount of moisture. I wanted to change the fluid anyway to Amsoil and did this along with changing the vent tube. The old vent was an open end inverted rubber pipe end with a 1/8" hole open to the atmosphere. I removed it and ran a 1/4" clear plastic tubing inside the cab. Yesterday it was above freezing the transmission was sweating, but inside the cab was dry, we'll see come spring if it did any good.

joe patterson · Jan 6, 2019

just finished changing transmission, loaderon my new holland tc30 hst tractor.this was 2bd time in two weeks, third time this year. new holland says this is caused by condensation. am planning to install a dessicant filter. had a lot of hydraulic equipment before without this problem. any input, and has anyone else else ever put a dessicant breather on a tc30.

Dakota_male · Jan 6, 2019

joe patterson said:
just finished changing transmission, loaderon my new holland tc30 hst tractor.this was 2bd time in two weeks, third time this year. new holland says this is caused by condensation. am planning to install a dessicant filter. had a lot of hydraulic equipment before without this problem. any input, and has anyone else else ever put a dessicant breather on a tc30.

Well it has been a few years +300 hours on the fluid since I vented it to inside the cab and no moisture since .