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Hydraulic system flush
- Thread starter Lil' Puss
- Start date
koecon
Well-Known Member
Changing the oil and filters is a good start
But you will most likely need to change at
least the filters several times. I think you
should consider where the water came from!
Does this machine have a coolant to oil hyd
cooler that may have failed?
Water will separate from oil over time and
it is heavier than most oils so it will collect
at the bottom of the tank where it can be
drained until you get pure oil.
Repeating this process will help also and then
I would run an oil sample through a local oil
analisys lab to monitor water and wear metals.
But you will most likely need to change at
least the filters several times. I think you
should consider where the water came from!
Does this machine have a coolant to oil hyd
cooler that may have failed?
Water will separate from oil over time and
it is heavier than most oils so it will collect
at the bottom of the tank where it can be
drained until you get pure oil.
Repeating this process will help also and then
I would run an oil sample through a local oil
analisys lab to monitor water and wear metals.
Nige
Senior Member
Other than physically draining the oil out of every cylinder, line, valve, & pump - no. Simple fact, there isn't a quick fix.
Thanks for the replies.
The oil cooler just consists of a heavily finned pipe about 24" long that is also the common suction line for the pumps, so no coolant contact possible. I believe the moisture is from condensation because the machine sat for a long time.
I'd thought about polishing the oil with a two micron coalescing filter and cycling the cylinders periodically but that would take quite awhile since the reservoir is about 15 gallons. The existing filter is just a 25 micron return line filter so that only keeps the gravel out.
I think what I will do (opinions appreciated) is change the reservoir oil and fit a coalescing filter element in series with the return line filter and then cycle all the hydraulic functions for about ten minutes. Wash, rinse, repeat two more times, changing the coalescing filter in between, and finally sending off a specimen to be analyzed. I'm trying to avoid taking all the cylinders and motors apart. So far the machine has sat for a week unused, so before I do anything, I'll check the reservoir with Kolor Kut and maybe be able to decant some water off.
The oil cooler just consists of a heavily finned pipe about 24" long that is also the common suction line for the pumps, so no coolant contact possible. I believe the moisture is from condensation because the machine sat for a long time.
I'd thought about polishing the oil with a two micron coalescing filter and cycling the cylinders periodically but that would take quite awhile since the reservoir is about 15 gallons. The existing filter is just a 25 micron return line filter so that only keeps the gravel out.
I think what I will do (opinions appreciated) is change the reservoir oil and fit a coalescing filter element in series with the return line filter and then cycle all the hydraulic functions for about ten minutes. Wash, rinse, repeat two more times, changing the coalescing filter in between, and finally sending off a specimen to be analyzed. I'm trying to avoid taking all the cylinders and motors apart. So far the machine has sat for a week unused, so before I do anything, I'll check the reservoir with Kolor Kut and maybe be able to decant some water off.
Last edited:
koecon
Well-Known Member
I think that is a good approach, just be
Ready to do more oil and filter changes
than you might expect.
Ready to do more oil and filter changes
than you might expect.
Nige
Senior Member
I agree with you about the source of the condensation, most likely to have been due to the machine sitting for a long while.
The problem with hydraulic oil is that like brake fluid it's hygroscopic and absorbs water, so the best way to get rid of the water is to drain the oil and that'll take the water with it.
I don't think Color Kut will work on water in hydraulic oil TBH, but I'm prepared to be proved wrong.
I personally think you won't be happy with the results of changing the tank oil + coalescing filter, etc, although on the face of it it's an extremely good idea.
Try this. Be warned it's at least a 2-man job, maybe better with 3: -
1. Drain the tank and every line that you can get to on the upper works of the machine up to & including the main control valve, so that would include the lines to/from the cooler and the pump. That should get the base machine clean-ish.
2. Every step from now on keep an eye on the tank level. It will go down and have to be topped up frequently.
3. Remove a line on the head end of each boom cylinder and drain the oil from both cylinders into a container. Refit the lines.
4. Loosen (don't remove) a line from the rod end of each boom cylinder. Start the engine and slowly raise the boom. It will take a while because the cylinders will be empty at the head end. Move the cylinders until they top out and the tighten the rod end hoses.
5. Repeat Steps 3 & 4 for the stick cylinder and the bucket cylinder.
6. Next the swing motor. Loosen a hose on one side of the motor and gently swing in that direction until you get clean oil. Tighten the connection, loosen on the opposite side of the motor and repeat for swing in the other direction.
7. Lastly the travel motors. Remove the case drain line to the tank (if fitted) at the motor end and drain the oil out into a container. Leave the case drain hoses disconnected. Loosen (don't remove) the "forward" line on one motor. Start the engine and use the implements to raise that track off the ground. Gently move the travel control to the forward position until you get clean oil coming out. At that point leave the same hose loose but put the travel control in reverse. That will bring clean oil through the return line and right through the motor. When you get clean oil tighten the connection. Repeat the process for the other track.
8. BTW. Did I mention keep an eye on the hydraulic oil level in the tank while you're doing all this .........??
The problem with hydraulic oil is that like brake fluid it's hygroscopic and absorbs water, so the best way to get rid of the water is to drain the oil and that'll take the water with it.
I don't think Color Kut will work on water in hydraulic oil TBH, but I'm prepared to be proved wrong.
I personally think you won't be happy with the results of changing the tank oil + coalescing filter, etc, although on the face of it it's an extremely good idea.
Try this. Be warned it's at least a 2-man job, maybe better with 3: -
1. Drain the tank and every line that you can get to on the upper works of the machine up to & including the main control valve, so that would include the lines to/from the cooler and the pump. That should get the base machine clean-ish.
2. Every step from now on keep an eye on the tank level. It will go down and have to be topped up frequently.
3. Remove a line on the head end of each boom cylinder and drain the oil from both cylinders into a container. Refit the lines.
4. Loosen (don't remove) a line from the rod end of each boom cylinder. Start the engine and slowly raise the boom. It will take a while because the cylinders will be empty at the head end. Move the cylinders until they top out and the tighten the rod end hoses.
5. Repeat Steps 3 & 4 for the stick cylinder and the bucket cylinder.
6. Next the swing motor. Loosen a hose on one side of the motor and gently swing in that direction until you get clean oil. Tighten the connection, loosen on the opposite side of the motor and repeat for swing in the other direction.
7. Lastly the travel motors. Remove the case drain line to the tank (if fitted) at the motor end and drain the oil out into a container. Leave the case drain hoses disconnected. Loosen (don't remove) the "forward" line on one motor. Start the engine and use the implements to raise that track off the ground. Gently move the travel control to the forward position until you get clean oil coming out. At that point leave the same hose loose but put the travel control in reverse. That will bring clean oil through the return line and right through the motor. When you get clean oil tighten the connection. Repeat the process for the other track.
8. BTW. Did I mention keep an eye on the hydraulic oil level in the tank while you're doing all this .........??
Nige
Senior Member
I thought not, but wasn't 100% sure.
The best way to completely remove all water from all parts of any hydraulic system, is to hook the problem piece of equipment to a vacuum dehydrator. This way one can clean and purify the oil in the tank while running the equipment's and all it's ancillaries forcing the dirty oil back to tank to be cleaned by the Vacuum dehydrator/purifier. This will not only clean and dry the oil, but all pumps, motors, cylinders, piping, hoses, valves and all parts of the hydraulic system without the cost of an oil change.