Changing hyd fluid--what about the fluid in the FEL?

[gordon21]

How do you handle a hydraulic fluid change when there is still several gallons in the cylinders of the FEL, log splitter, backhoe, etc? There will still be trapped old fluid in all these cylinders. I just filled the cylinders in my new log splitter and it took over 2 gallons for just that one cylinder. Therefore I assume there is another 8-10 gallons in the FEL and backhoe. That could mean 12 gallons of fluid that will not get changed. Seeing since the tranny itself only holds 4 gallons, that means I am replacing only 33% of the fluid. this does not sound right.

[Doc_Bob]

Therefore I assume there is another 8-10 gallons in the FEL and backhoe. That could mean 12 gallons of fluid that will not get changed. Seeing since the tranny itself only holds 4 gallons, that means I am replacing only 33% of the fluid. this does not sound right.

I doubt my FEL has gallons in it. Maybe?
Bob
PS I chnaged 13 gallons of hydro fluid on my TN70A. Dilution is the solution!

[wrenchturner]

I understand your concern and do believe a significant volume of fluid is retained in the hoses, pump and cylinders. However, I would not be overly concerned unless there is contamination. Car automatic transmissions hold only about 4 quarts of fluid in the pan and filter with the other approximate 8 quarts in the rest of the system. I would flush the system in a smiliar way I flush automatic transmissions without expensive machinery. First drain and fill the sump. Then fabricate a hydraulic hose with only one fitting on the end to couple with the return line from the loader, backhoe ect. cylinders. Make the hose long enough to reach a bucket. Start with the cylinders retracted then extend the cylinders. Check the bucket and if you pump out a gallon, add a gallon to the sump. Reconnect the hoses then go to the next set of cylinders. Just be careful and not run the system dry.

[Dirthog]

Don't be concerned with the little bit what is in the rest of the system even in the large dozers loaders and excavators we sell and service the only time we are concerned is if you have a major blow up in the system and have not had one come back with trouble in the last 33 years I have been a mechanic there

[RalphVa]

I think the main reason for a fluid change, particularly the one at 50 hours, is to drain off any fluid that has tiny bits of metal in it that didn't get filtered out and to also replace the filter that would have stopped bigger metal particles. I've "changed" fluid in my power steering on my car by just sucking out the old fluid and putting in new. All fluid in the lower system areas and hoses stayed there. Changing stopped seal oil fling. This is the major reason for the fluid change at 200 hours, just to get enough new stuff in there to replace the additives that have gone zonk to help keep the seals swelled and to remove oxidized oil.

Ralph

[Soundguy]

How do you handle a hydraulic fluid change when there is still several gallons in the cylinders of the FEL, log splitter, backhoe, etc? There will still be trapped old fluid in all these cylinders. I just filled the cylinders in my new log splitter and it took over 2 gallons for just that one cylinder. Therefore I assume there is another 8-10 gallons in the FEL and backhoe. That could mean 12 gallons of fluid that will not get changed. Seeing since the tranny itself only holds 4 gallons, that means I am replacing only 33% of the fluid. this does not sound right.

If you are real concerned about it.. get a cheapy 20$ bucket of utf from walmart.. change it with that.. cycle thru it for 20 minutes.. then change again with whatever oil you like.. only adds 20$ to the cost.. and you have diluted the 'old' oil down in the system by a huge factor..

Soundguy

[daTeacha]

But then your working oil is partially cheapy stuff that may or may not meet specs for your machine.

[Soundguy]

Obviously he needs to check his hyd specs before randomly dumping oil into it....If his tractor calls for UTF.. then he obviously needs to check the specs on the conatainer for what he adds.. if it calls for udt.. he's stuck.. I havn't found any cheap udt...

I'd rather have inexpensive but properly spec'ed clean oil in my hyds than old, dirty, wet name brand oil in my hyds -ANY- day of the week.

Soundguy

[Doc_Bob]

Obviously he needs to check his hyd specs before randomly dumping oil into it....If his tractor calls for UTF.. then he obviously needs to check the specs on the conatainer for what he adds.. if it calls for udt.. he's stuck.. I havn't found any cheap udt...

I'd rather have inexpensive but properly spec'ed clean oil in my hyds than old, dirty, wet name brand oil in my hyds -ANY- day of the week.

Soundguy

Ditto
Bob

[CurlyDave]

I was about to post a similar question when I found this thread.

There is a significant amount of oil in your attachments. I got a rock bucket with 2 grapple cylinders and a thumb with one cylinder a couple of weeks ago and was astonished to discover that my hydraulic fluid was 2 gallons low after installing them, with a nominal system capacity of 9.7 gallons.

Somehow it seems to me that changing fluid in all the implements I have is going to be a PITA when change time comes, and I am wondering about a different strategy.

What if I just drain the reservoir and fill it with inexpensive UTF, and keep doing this at about 1/3 the recommended interval. Sure, it is all going to get mixed up in the system, and I will never have 100% new oil, but I will have relatively fresh oil all the time.

And, the cost is going to be about the same as for using name brand oil with a much more thorough drain & implement flush on a less frequent schedule.

The way I have always understood oils is that the expensive synthetics can go longer between changes than dino oil, but wear is just about the same if I change the dino more frequently than the recommended interval.