1994 EX60 URG hydraulic issues works then practically stops

[Tomco]

Hi all wee the repair to the final drive has gone well, no leaks, but what I thought was associated issue obviously isn't
Here's the problem, cold start everything seems to operate as it should 5 mins in and the fun begins, there seems to be an issue with the hydraulics, where I tend to loose hydraulic power, this is not the engine bogging down , the easiest way to describe it , I cannot slew the machine or its incredibly slow MM at a time , if I lower the engine speed back to idle it comes back to life, its the same with the track motors and everything else, This had been going on for a while now and I related it to low oil perhaps due to to the track motor leak , so much for my ideas.
seems that at times under full power it tends to work then just stops , so I need to idle the machine give everything a jiggle on the stick and we can increase power again .
Does anyone have any ideas, its a great little machine a bugger to get into because its so small just wondering what to do next , it has pressure as cold its ok this slow everything down and its ok seems to me a possible relief valve any help would be appreciated, keep on diggin Tommy

 

[Tomco]

So just out of curiosity I gave the machine a run and yep cold it all works perfectly 10-15 min in and the hydraulics seem to stop until I idle it down and then everything comes back again but goes out again when I power back up past 25 %

 

[ebaikie]

It could be the flex coupling between the engine and the hydraulic pump, or spun pump shaft splines.
Spins under load, catches again at idle.

 

[Tomco]

It could be the flex coupling between the engine and the hydraulic pump, or spun pump shaft splines.
Spins under load, catches again at idle.

sort of ruled that out as it only does it when its had about 15 mins work never does it from start up cold and I can work it hard on start up and it doesn't seem to have an issue, its almost like a relief valve sort of thing ,Im not sure but we will find it somehow

 

[Deere tech]

Sounds like your right about it being hydraulic pressure related. It would be nice to know what the pressure is when cold and then when hot.
I do have an oddball of a thought. Maybe the alternator is overcharging and the controller is shutting down at the voltage spikes to protect itself.

 

[Tomco]

Hi all wee the repair to the final drive has gone well, no leaks, but what I thought was associated issue obviously isn't
Here's the problem, cold start everything seems to operate as it should 5 mins in and the fun begins, there seems to be an issue with the hydraulics, where I tend to loose hydraulic power, this is not the engine bogging down , the easiest way to describe it , I cannot slew the machine or its incredibly slow MM at a time , if I lower the engine speed back to idle it comes back to life, its the same with the track motors and everything else, This had been going on for a while now and I related it to low oil perhaps due to to the track motor leak , so much for my ideas.
seems that at times under full power it tends to work then just stops , so I need to idle the machine give everything a jiggle on the stick and we can increase power again .
Does anyone have any ideas, its a great little machine a bugger to get into because its so small just wondering what to do next , it has pressure as cold its ok this slow everything down and its ok seems to me a possible relief valve any help would be appreciated, keep on diggin Tommy

UPDATE: Not sure how correct this is but I was told it sounds like the gear pump is worm and cavitation is the issue , just wondered if anyone might have any ideas , regards Tom

 

[Tomco]

Sounds like your right about it being hydraulic pressure related. It would be nice to know what the pressure is when cold and then when hot.
I do have an oddball of a thought. Maybe the alternator is overcharging and the controller is shutting down at the voltage spikes to protect itself.

Just realized we used a 68 grade oil when it should be 46 wonder if thats been the issue perhaps

 

[Diesel Dave]

It sounds like intermittent hydraulic pump valve plate to cylinder head separation (lift).
Deere 892D’s were famous for that.
Would lose one pump completely, idle engine down for 5-10 seconds and then back to full throttle and voila performance would come back like nothing happened…until the next time.
Back in the day the parts dept always had 2 cylinder heads and valve plates on the shelf.
A pressure test is the way to go.