My Hitachi EX270LC-5 pump Transmission leaked all of its gear oil out in 4-5 hours of use. It was dripping from the bell housing. Clearly I need the lube in there but I really don’t want to pull off the pump. Any suggestions?
I'm sorry but my guess is the pumps have to come off so you can pull that gear box. The input shaft seal is likely doing the leaking, and the question is, why? I'd be looking at the coupler being shot between the engine and gearbox. I had that experience with a Cat 235C. I told the boss there was a funny vibration I did not like. He said keep digging. The coupler let go and the vibration was gone, as were all functions. It was not a convenient location, either.
Hmm. I just also saw this in another thread. Hitachi Pump Transmission Leak I'm just getting to know this EX270LC. Overall it seems in good condition, but it does have a gear oil leak from the pump transmission. It only leaks when the machine is at operating temperature and the oil is warm. Just to clarify what is leaking, the pump transmission is the part that the... HeavyEquipmentForums
There you go. The only possible help would be the plugged vent in the filler plug. It is very unlikely to be the cause though. Do look hard at the coupler as I mentioned. All the power goes through it, and as it goes out it can put a side loading on the input shaft and bearing and seal.
Interesting about the coupler. I’ll give it a detailed look when I pull it off. I heard a loud gear whining for about 30 minutes or so before I decided to shut it down. I just thought it was a normal sound until I really listened to it and was looking all over the machine for the cause and saw the pump leaking profusely. More to come. The service manual is worthless on the removal procedure 3 steps. Turn off engine, remove hoses, remove pump. Duh!
You're there, change the coupler. Don't even question it. JMO
Advice taken which part ? Sorry I’m a newbie at this and didn’t find it on the diagram
https://partscatalog.deere.com/jdrc/sidebyside/equipment/64424/referrer/navigation/pgId/181001 . .
Outstanding! Would it be possible that the pumps need rebuilding if on my long reach it really struggles with lifting a full bucket when the bucket is close to the cab and cannot lift it when further away. Or is that typical behavior? It doesn’t sound like the motor loads down or anything. The boom just doesn’t go up any higher until I stick in. I rebuilt the boom cylinders so I know they are in good condition.
Do a pressure check before doing anything else.
92U. Thank you and got a test kit ordered. After scouring my manuals I don’t see a pressure test procedure or pressure requirement (desired reading). On YouTube for another machine they were checking for 300 bar for the main pumps and pilot was 30 bar. In the last video they replaced the main relief valve versus working on the pump. How would one know to swap the valve vs rebuild the pump (for Hitatchi machine with 12k hours)? Short video on where the test ports are but no desired readings Non English video for pressure test procedure
I'd start with checking the pressure on the weak circuit. If it won't build to spec then you'll need to figure out why. Could be the relief is set too low, could be weak pumps. Further checks will be needed to verify the pumps if you have to go that route.
Keep in mind if it is a true long boom and stick, the numbers are different. I don't know how they do it, but volumes are reduced to keep from breaking them. That is all I know from experience operating long reach machines.