Recently I decided to rebuild my engine mounted hydraulic pump because it was starting to leak near the snap ring and suction line, plus there was some jerkiness at times in the hydraulics.
All went well, rebuilt the pump, which included replacing a worn wobble shaft and the cone bearing. After this, I had good hydraulics on the 3 point for a few days. While doing some heavy boom pole lifting, I did notice it was still a little jerky, so I decided to bleed the pump real quick while the engine was at idle (big mistake). I unscrewed the plug too much and it fell out of my hands, along with a several gallons of hydraulic fluid before I had the brains enough to shut off the engine (it was still flowing out at this point, so it didn't suck it dry). In the barn I had a gallon of hydraulic fluid so I poured that into the tractor, started up and the 3 point worked fine (but also didn't have a load on it either). I give this detail of my clumsiness, because what comes next I don t know if it is related or just a coincidence.
After topping off the hydraulic fluid the next day, I started the tractor and put an 800lb load on a boom pole and that is when I noticed problems. With nothing on the 3 point, it would raise fine, but with a boom pole by itself or even a small trailer hitch attached, it might raise an inch after 10 minutes when idling. If I increased the RPMs to 1400, it would take about a minute to raise. If I took my hands to raise the lift arms with the implement on, then the tractor would hold the height and not drop. Flow control valve is open all the way and the draft control is turned off.
Not knowing what else to do, I decided to rebuild the lift cover, mainly to see if any of the valves were stuck. Everything looked fine, installed new all the seals and also replaced a broken spring that connects to the sump return tube (part # C5NN6N400C). The valves in the lift cylinder moved free, the hydraulic fluid is in great condition, a quick visual of the return filter looked good. There is also flow from the bleeder screw at the pump.
With all of this, after reassembly I still get nothing. I then decided to buy a cheap gauge kit (Vevor from Amazon) and connected it to the hydraulic cover blocking plate. Reading zero pressure, so I'm wonder if this is accurate or do I need to do an additional step to get a good reading? (or is it due to a cheap gauge)
After all of this, with some helpful advise from Ultradog on another forum website, I screwed a hose barb to the pump and looped a clear hose back to the fill hole behind the seat. Ran the tractor for almost an hour while working on other things in the barn, hoping this would clear any air in the system. While doing this, I was getting a steady flow from the pump and I suspect it would be the 5 gpm that the pump is rated for. However, still no change, no hydraulics pressure.
At this point, I've ordered another rebuild kit after talking with Ultradog. This is due to the fact that I'm reading zero pressure at the block and the suction tube looks to be in good shape (no major rust or other damage).
Before opening up the pump next week, should I be looking at other things too? Today I took the side sheet metal off to get a better look at everything and noticed a very slight fluid build-up near the bottom of the suction line. Think air might be getting through?
I don't mind tearing into the pump again, but I've spent a month on this hydraulic issue and time is my biggest aggravation right now. I need to get the tractor back to work on the property and want to avoid long delays waiting for parts if there is also something else I could be looking into.
Any advice would be appreciated.
This post was edited by supton on 04/14/2023 at 09:58 pm.
All went well, rebuilt the pump, which included replacing a worn wobble shaft and the cone bearing. After this, I had good hydraulics on the 3 point for a few days. While doing some heavy boom pole lifting, I did notice it was still a little jerky, so I decided to bleed the pump real quick while the engine was at idle (big mistake). I unscrewed the plug too much and it fell out of my hands, along with a several gallons of hydraulic fluid before I had the brains enough to shut off the engine (it was still flowing out at this point, so it didn't suck it dry). In the barn I had a gallon of hydraulic fluid so I poured that into the tractor, started up and the 3 point worked fine (but also didn't have a load on it either). I give this detail of my clumsiness, because what comes next I don t know if it is related or just a coincidence.
After topping off the hydraulic fluid the next day, I started the tractor and put an 800lb load on a boom pole and that is when I noticed problems. With nothing on the 3 point, it would raise fine, but with a boom pole by itself or even a small trailer hitch attached, it might raise an inch after 10 minutes when idling. If I increased the RPMs to 1400, it would take about a minute to raise. If I took my hands to raise the lift arms with the implement on, then the tractor would hold the height and not drop. Flow control valve is open all the way and the draft control is turned off.
Not knowing what else to do, I decided to rebuild the lift cover, mainly to see if any of the valves were stuck. Everything looked fine, installed new all the seals and also replaced a broken spring that connects to the sump return tube (part # C5NN6N400C). The valves in the lift cylinder moved free, the hydraulic fluid is in great condition, a quick visual of the return filter looked good. There is also flow from the bleeder screw at the pump.
With all of this, after reassembly I still get nothing. I then decided to buy a cheap gauge kit (Vevor from Amazon) and connected it to the hydraulic cover blocking plate. Reading zero pressure, so I'm wonder if this is accurate or do I need to do an additional step to get a good reading? (or is it due to a cheap gauge)
After all of this, with some helpful advise from Ultradog on another forum website, I screwed a hose barb to the pump and looped a clear hose back to the fill hole behind the seat. Ran the tractor for almost an hour while working on other things in the barn, hoping this would clear any air in the system. While doing this, I was getting a steady flow from the pump and I suspect it would be the 5 gpm that the pump is rated for. However, still no change, no hydraulics pressure.
At this point, I've ordered another rebuild kit after talking with Ultradog. This is due to the fact that I'm reading zero pressure at the block and the suction tube looks to be in good shape (no major rust or other damage).
Before opening up the pump next week, should I be looking at other things too? Today I took the side sheet metal off to get a better look at everything and noticed a very slight fluid build-up near the bottom of the suction line. Think air might be getting through?
I don't mind tearing into the pump again, but I've spent a month on this hydraulic issue and time is my biggest aggravation right now. I need to get the tractor back to work on the property and want to avoid long delays waiting for parts if there is also something else I could be looking into.
Any advice would be appreciated.
This post was edited by supton on 04/14/2023 at 09:58 pm.
