hydraulics bleeding

[brokefarmer]

Bought a 3600 with hydraulic problems they had to be bled before the lift was raised and they were very slow. I pulled the lift cover changed all O-rings and replaced the return filter and cleaned the screen in the sump.

Got it all back together bled the system hooked to a heavy bush-hog and it would lift fast and easy. I shut it off went and eat dinner came back and it wouldnt lift. Bled it again and it worked perfect. I bush-hogged for several hours with bush-hog in same postion, got finished and bush-hog would not lift.

I pulled the suction line from the pump replaced the o-ring inspected the line for cracks and leaks and found none. You can bleed the pump and every thing works great for about 5 mins and then it slowly starts to get jerky (air in the system)until it finally gets enough air in it it will quit lifting.

Any ideas where the air is coming from? Thanks for any help in advance I need to get this working.

 

[Soundguy]

Suction side is about the only place.. if it is doing it while running.

I'd check the? compression type fitting at the pump as well as orings ont he plumbing to the back for the suction side especially.

Soundguy

 

[brokefarmer]

Thanks for the reply Soundguy, I pulled the suction side tube off...again, I pressurized the tube with air and sprayed with soapy water and saw no bubbles. I didnt realize the first time that the elbow that screws to the case had an o-ring too (didnt remove it last time...silly me) so I replaced it and both of the o-rings on the tube...again. It seems okay so far, we will see if it lifts after supper.

Thanks again!

 

[JC-jetro]

Bought a 3600 with hydraulic problems they had to be bled before the lift was raised and they were very slow. I pulled the lift cover changed all O-rings and replaced the return filter and cleaned the screen in the sump.

Got it all back together bled the system hooked to a heavy bush-hog and it would lift fast and easy. I shut it off went and eat dinner came back and it wouldnt lift. Bled it again and it worked perfect. I bush-hogged for several hours with bush-hog in same postion, got finished and bush-hog would not lift.

I pulled the suction line from the pump replaced the o-ring inspected the line for cracks and leaks and found none. You can bleed the pump and every thing works great for about 5 mins and then it slowly starts to get jerky (air in the system)until it finally gets enough air in it it will quit lifting.

Any ideas where the air is coming from? Thanks for any help in advance I need to get this working.

There is one little other thing to consider. On my 1700 passed the 3-point rate of drop needle valve there is a spring loaded check valve that is normally closed by spring action. The spring is pretty stiff and the function of this thing is to relive shock pressure.... let say you are carrying on your 3 point something very heavy and you're on a bouncy dirt road and going a bit faster than you should.. then this relief device squirts a little bit of tapped oil behind lift piston in to the differential housing before the nylon lift cylinder seal (ring) is damaged. You might have this and the little ball bearing may be totally off the seat , damaged or stock open with some impurity.


JC,







JC.