backhoe hydraulics weak on just purchased Jinma 283 le

[BryanMitchell]

Hey group,

Please relieve some of my "freak out."
I just bought a used Jinma 283 le today and the backhoe hydraulics are causing me to have a mini stroke. I picked up the tractor and the back hoe was not attached. I personally hooked up the auxiliary pump to the little removable plate area above the PTO. Back hoe worked while at the guys house so we loaded it onto a trailer hauled it 15 miles down a gravel road, unloaded it and started playing with my new toy and the dang thing started fine then just seemed to loose all pressure. I got about half of a scoop of dirt in the dipper and it couldn't even pick itself back up. I thought it may have had low fluid so I checked the on board hyd. tank and added about a liter, that didn't change things either. I shut the tractor down for a couple of minutes and looked things over, no leaks, or anything. So I started it back up and for about 3 minutes, or until I started moving the motions around again it had power then just died off again.
It acted like there may have been air in the lines I think or maybe the little pump wasn't turning fast enough to keep up with the demand? It didn't seem to matter what the rpms were either.
Is it possible that air could have gotten in, and how long should I have run it to get the air out? I also noticed when I hooked it up that when I unbolted the little cover plate that the pump mounts up to no hyd fluid came out like I was expecting, the guy said that little area should refill after the pump starts turning, if that is still empty could that cause this issue?
I called the guy and asked if it had ever done this to him and of course it hadn't. I plan on taking off the pump to ensure it is actually turning tomorrow...???
thanks in advance for any advice.
Bryan

 

[oldnslo]

Hey group,

Please relieve some of my "freak out."
I just bought a used Jinma 283 le today and the backhoe hydraulics are causing me to have a mini stroke. I picked up the tractor and the back hoe was not attached. I personally hooked up the auxiliary pump to the little removable plate area above the PTO. Back hoe worked while at the guys house so we loaded it onto a trailer hauled it 15 miles down a gravel road, unloaded it and started playing with my new toy and the dang thing started fine then just seemed to loose all pressure. I got about half of a scoop of dirt in the dipper and it couldn't even pick itself back up. I thought it may have had low fluid so I checked the on board hyd. tank and added about a liter, that didn't change things either. I shut the tractor down for a couple of minutes and looked things over, no leaks, or anything. So I started it back up and for about 3 minutes, or until I started moving the motions around again it had power then just died off again.
It acted like there may have been air in the lines I think or maybe the little pump wasn't turning fast enough to keep up with the demand? It didn't seem to matter what the rpms were either.
Is it possible that air could have gotten in, and how long should I have run it to get the air out? I also noticed when I hooked it up that when I unbolted the little cover plate that the pump mounts up to no hyd fluid came out like I was expecting, the guy said that little area should refill after the pump starts turning, if that is still empty could that cause this issue?
I called the guy and asked if it had ever done this to him and of course it hadn't. I plan on taking off the pump to ensure it is actually turning tomorrow...???
thanks in advance for any advice.
Bryan

Things to check:

1) is there a sight gauge or dip stick on the reservoir / tank? If yes make sure it is full.
2) Is the the pump dive shaft keyed or spline? If keyed check to make sure the key is installed correctly and has not fallen out.
2a) If possible confirm the pump is turning while trying to operate the back hoe.
2) Since you are mounting this pump on the back of the tractor I presume their are hoses going to the remote reservoir and the control valves. Were these removed for any reason? Make sure the inlet fittings are tight. Possible from moving the pump around these could have worked lose.

If all else fails post a few pictures of how the pump is mounted and plumbed. They might help identify potential problems.