Hydraulic oil level

[NHwoods]

After 17 years i traded my L3240 in for an MX6000. Both HST. Never had an issue with the hydraulic oil in the 3240. The MX6000 has a sight glass which has never been easy to read and after 12 months, was completely unreadable. After multiple conversations and forum reviews i finally added 1 oz of JD red hydraulic oil dye. I figure that it was 8/10,000's of the oil and unlikely to have any effect. Except it did make the oil easily readable. I have been using my Bh92 backhoe for the last 2 weeks and the oil level has stayed mid glass in my daily checks. I removed the backhoe last night and this morning the oil was down almost a gallon. No leaks anywhere, no drips on the garage floor, no oil wet spots at filter/hoses/etc. I can't think of any reason the backhoe would be acting as an oil reservoir. Does anyone have any ideas???

 

[SAR Tracker]

Not a hydraulic expert by any means, but if a cylinder or 2 were retracted when the "full" sight was made, then extended (and remained that way) to remove the BH, would that account for the "missing" fluid from the tank?

 

[NHwoods]

Not a hydraulic expert by any means, but if a cylinder or 2 were retracted when the "full" sight was made, then extended (and remained that way) to remove the BH, would that account for the "missing" fluid from the tank?

I'm not an expert either and that's an interesting thought. I will do some more research as i though there was oil on both sides of the internal seal that pushed the cylinder in or out depending on the valves.

 

[PoTreeBoy]

I'm not an expert either and that's an interesting thought. I will do some more research as i though there was oil on both sides of the internal seal that pushed the cylinder in or out depending on the valves.

When the cylinder is extended, the volume is full of fluid. When it's retracted, the rod displaces a substantial volume of fluid, even though the annular space between the rod and cylinder is 'full', so the total volume of fluid in the cylinder is less.