HELP! 743 Hyd.

[lfutrell]

I just repacked the lift cylinders on my 743, I ran them up and down a few times to get rid of the air. I then picked up a couple small buckets of dirt (so far so good) I went back and picked up a bigger load of dirt (not more than it can handle) and the lift and tilt hyd's quit working, 45sec. to a min. later the drive hyd quit. the hyd light in the console is lit. I thank you for any help ypu can give. Larry

 

[Tazza]

Are any fittings loose? The light coming on means there is low charge pressure. You didn't leave anything in the cylinders? no caps or plugs?

 

[lfutrell]

Are any fittings loose? The light coming on means there is low charge pressure. You didn't leave anything in the cylinders? no caps or plugs?

No, nothing loose, nothing leaking, full of oil, nothing left in the cylinders, the light never goes out when you start the machine, there is no pressure anywhere including the aux.(put a hose on it and it won't even pump the oil out.

 

[Tazza]

No, nothing loose, nothing leaking, full of oil, nothing left in the cylinders, the light never goes out when you start the machine, there is no pressure anywhere including the aux.(put a hose on it and it won't even pump the oil out.

Does the machine still move?
I wonder if the U-joint could have let go or something. You did say it was a gradual decline, so i would suspect its not that.....
No flow from your aux ports means there is no oil coming from or to your hydraulic pump. It sounds like something has gotten stuck causing a restriction.
Its possible that the shaft linking the pumps together has gone too. There are so many possible things, but none of which anyone can say for sure its THIS.
If you remove the hydraulic pump, get someone to turn the engine with a spanner, see if the shaft still rotates. If so, the link between the pumps is still ok.

 

[lfutrell]

Does the machine still move?
I wonder if the U-joint could have let go or something. You did say it was a gradual decline, so i would suspect its not that.....
No flow from your aux ports means there is no oil coming from or to your hydraulic pump. It sounds like something has gotten stuck causing a restriction.
Its possible that the shaft linking the pumps together has gone too. There are so many possible things, but none of which anyone can say for sure its THIS.
If you remove the hydraulic pump, get someone to turn the engine with a spanner, see if the shaft still rotates. If so, the link between the pumps is still ok.

Well, I drained the oil tank thru the sending unit in the port valve, so there is no restriction in the line to there, I took the end off of the pump and the shaft is turning all the way thru from the motor, any ideas are welcome. Thanks (Puzzled)

 

[lfutrell]

Well, I drained the oil tank thru the sending unit in the port valve, so there is no restriction in the line to there, I took the end off of the pump and the shaft is turning all the way thru from the motor, any ideas are welcome. Thanks (Puzzled)

Problem Found, One of the vanes broke and wedged in the pump, twisted the end off of the shaft, just a matter of getting parts and putting it back together. thanks for the help.

 

[Tazza]

Problem Found, One of the vanes broke and wedged in the pump, twisted the end off of the shaft, just a matter of getting parts and putting it back together. thanks for the help.

Ouch... At least you found it. Just really weird it happened after the cylinders were done, just bad timing i guess.
You know these parts are available aftermerket? you don't need to get them off the dealer.