L48 Hydraulic temp ?

[DMS]

Hi all, I just found this forum and it looks like it's packed with info! I have a question for a tech minded person. I just replaced the hydraulic pump on my L48 and according to the manual, the max operating temp is 140 F. I have used an infrared thermometer to measure the temp of various hydraulic parts and after use it reads about 180. I was told that this is normal by the service department. It make sense as the tractor is not running hotter than normal. However the manual contradicts common sense, as any hydraulic system I have encountered runs very hot. Anybody know what their operating temps are? ( for any HST Kubota, for that matter) I do know that the filters are new, one pump is new, and the other is within the factory specifications, all of the backhoe valves are in the right position, and any of the other causes for high temps are not present. Thanks in advance, I am off to scour the rest of this site.

[Drawbar]

It is not polite to answer a question with a question, but in this case I must. Certainly no disrespect intended...

My question is, since the machine has some age, has any of the hydraulic lines been replaced? Specifically I would look around the tractor and loader area and see if any steel hydraulic lines have been replaced with rubber hoses.

Those steel lines are designed into the system for economy and cooling. Often times people do not have the tubing benders and flairing tools to bend the pipes so they replace them with flexible rubber hydraulic hoses. Those rubber hoses are flexible but the coating keeps the heat in. Add one of two of these lines here and its no big deal. Replace several of those steel lines with rubber hoses and you are starting to defeat part of your hydraulic cooling system.

Probably a long shot in any case, but that could be a surprising cause of your overheating hydraulic system.

[Mickey]

Don't know a thing about your tractor so take this for what it's worth. Your comment about conflict between the manual and what you are actually seeing wouldn't be the first time I've seen errors in a manual. If the guys in the shop say 180° is normal, I'd take their word for it.

Following the manual for adjusting the timing on a JD bailer cost me several broken parts and I also wondered what I did wrong. Talked to the shop and the first words out of their mouth was "if you followed the manual, that's the problem".

[THETOOLMAN]

I have L4300dt . when In work it REALLY HARD it seems to run hotter hydraulic than I feel it should. But the engine never gets hotter . So i figure thats just one of those things.
Dan