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Dan, Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 5553
Experience:  17+ yrs. shop and field experience with all major brands of heavy equipment, trucks and farm equipment - 1995 WyoTech graduate.
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Dan, we have an JD8440 that the hydraulics went out on.

Customer Question

Hi Dan, we have an JD8440 that the hydraulics went out on. It was working when my brother was chiseling and then it stopped. It steers fine, breaks fine and turns fine but 3-point lift will not work or will the hydraulics when we hook up the disc? Doesn't sound like a pump too me that went out but perhaps a valve or bad o-ring. Any advice?
Submitted: 2 years ago.
Category: Agriculture and Farm Equipment
Expert:  Dan replied 2 years ago.
Hi, It's Dan. Thanks for the request. Check the pump drive coupling at the front of the engine as they have been known to fail resulting in the pump not turning. Also, the pumps themselves are known for piston problems internally and all it takes as one or two pistons to stick or have a failure or problem and you will not get system pressure. Some models have a destroke valve at the pump to destroke the pump while cranking over the engine. Check to see if this valve is causing the pump to destroke when it should not be. Check those items first and let me know if we need to dig deeper into this and I will be glad to help.
Expert:  Dan replied 2 years ago.
Hi, Did you get this resolved? I wanted to follow up to see what you found and if my information was helpful to you or if you still needed more help? Let me know and I will get this question closed out for you if you don't need further help with this. Please feel free to rate or accept if you found my information helpful as that is how the experts receive credit for their time helping on the site.