Marlowe
Gold Member
Hi folks,
Earlier this week I posted regarding hydraulic oil in my crankcase. Logic suggested it was coming from a seal in the hydraulic pump, which proved to be correct; it was the input shaft seal. It's amazing how fast a pump can fill a crankcase when the seal goes bad. I was lucky enough to find legible numbers on the seal, and double lucky to find a nice enough fellow on a parts counter at Bearing Distributors who was willing to cross reference the seal to find one available somewhere in the world. Then I asked him if he could have it by the next day. Not only could he, it was shipped direct to me so I wouldn't have to make a trip to go get it. Now that's good customer service, for only a seal.
For those who have never tackled it, a hydraulic pump is fairly simple. The only intimidating thing about one is to convince yourself you can do it, then dive right in. Replacing the seal and putting it back together was easy enough. Putting it back on the tractor was straightforward, even in the rain and the dark. You gotta' do what you gotta' do. Then I refilled the hydraulic oil reservoir/transmission. I was amazed by how much oil those things can hold. I guess that's why they only sell that stuff in five gallon buckets. And a little Mitsubishi diesel engine holds lots of oil as well. A five dollar seal cost me nearly fifty bucks worth of oil.
Okay, all lubed up and ready to fire it up. It purred fine, but nothing from the hydraulics. No hitch lift or FEL. Not even a twitch. I shut it back down, double checked my oil level, and scratched my head. What I observed was that my pump was about eight inches higher than my oil level in the reservoir. Mechanical pumps like my Mitsubishi 1801 uses are not self priming. If there is air in the incoming line it will never prime, and I imagine it would soon enough seize up from lack of lube.
How to prime the pump, I wondered. It was late, I was wet, and fairly disgusted, so I decided to sleep on it. What I dreamed up was to pressurize the hydraulic reservoir with air pressure, then crack open the incoming oil line. The air pressure should push the fluid into the pump. I had a plan.
Luckily I was able to find enough rubber doohickeys to fabricate a plug for the transmission fill cap hole with a hole in it for air pressure input. I tested my contraption and was pleased to see it work. Then I backed off on the bolts holding the incoming oil line on the top of the pump, just enough to allow it to leak. Then I applied air pressure and crossed my fingers. Soon enough, I saw oil start to leak out, mixed with air, then just oil. While maintaining air pressure, and the slow leak, I tightened the bolts sealing things back up.
Now for the moment of truth. I fired it up again. With fingers crossed I hit the joy stick for the FEL. I'm a happy man. Everything works again.
I may not have done things by the book, but I don't have one. I've written this short story for those who may run across a similar problem in the future, in the hope that it will help a buddy out. I'm sure not all tractors are alike, but all hydraulic systems work by the same principals as best I can tell.
Good luck with yours,
Tom
Earlier this week I posted regarding hydraulic oil in my crankcase. Logic suggested it was coming from a seal in the hydraulic pump, which proved to be correct; it was the input shaft seal. It's amazing how fast a pump can fill a crankcase when the seal goes bad. I was lucky enough to find legible numbers on the seal, and double lucky to find a nice enough fellow on a parts counter at Bearing Distributors who was willing to cross reference the seal to find one available somewhere in the world. Then I asked him if he could have it by the next day. Not only could he, it was shipped direct to me so I wouldn't have to make a trip to go get it. Now that's good customer service, for only a seal.
For those who have never tackled it, a hydraulic pump is fairly simple. The only intimidating thing about one is to convince yourself you can do it, then dive right in. Replacing the seal and putting it back together was easy enough. Putting it back on the tractor was straightforward, even in the rain and the dark. You gotta' do what you gotta' do. Then I refilled the hydraulic oil reservoir/transmission. I was amazed by how much oil those things can hold. I guess that's why they only sell that stuff in five gallon buckets. And a little Mitsubishi diesel engine holds lots of oil as well. A five dollar seal cost me nearly fifty bucks worth of oil.
Okay, all lubed up and ready to fire it up. It purred fine, but nothing from the hydraulics. No hitch lift or FEL. Not even a twitch. I shut it back down, double checked my oil level, and scratched my head. What I observed was that my pump was about eight inches higher than my oil level in the reservoir. Mechanical pumps like my Mitsubishi 1801 uses are not self priming. If there is air in the incoming line it will never prime, and I imagine it would soon enough seize up from lack of lube.
How to prime the pump, I wondered. It was late, I was wet, and fairly disgusted, so I decided to sleep on it. What I dreamed up was to pressurize the hydraulic reservoir with air pressure, then crack open the incoming oil line. The air pressure should push the fluid into the pump. I had a plan.
Luckily I was able to find enough rubber doohickeys to fabricate a plug for the transmission fill cap hole with a hole in it for air pressure input. I tested my contraption and was pleased to see it work. Then I backed off on the bolts holding the incoming oil line on the top of the pump, just enough to allow it to leak. Then I applied air pressure and crossed my fingers. Soon enough, I saw oil start to leak out, mixed with air, then just oil. While maintaining air pressure, and the slow leak, I tightened the bolts sealing things back up.
Now for the moment of truth. I fired it up again. With fingers crossed I hit the joy stick for the FEL. I'm a happy man. Everything works again.
I may not have done things by the book, but I don't have one. I've written this short story for those who may run across a similar problem in the future, in the hope that it will help a buddy out. I'm sure not all tractors are alike, but all hydraulic systems work by the same principals as best I can tell.
Good luck with yours,
Tom
