42' 9n hydraulic lift problems

William S

Member
Hello,
I have a 42' 9n and at first the hydraulic lift wouldn't lift with any implement attached to it. Although, the lift would go up with nothing attached.
I removed the inspection plates, both of them, and no obvious leak was found. Then I checked the 'Spring, Hydraulic lift draft control' and has quite abit of slop when the lift was up. I tried to turn the yoke but as I have read, it's stuck solid to the plunger.
Then something changed, now the lift would not go down. So, I reached through the inspection port and felt for the control valve at the bottom of the forks. After some effort I located the valve or what felt like a 'T' and reattached it to the bottom of the fork. (I'm glad no one was watching as I was hugging the centercase, with one arm in either port) Well, the lift went down and then up and stayed up. Rather than beat my head on the differntial, I figured I would ask for some help.
I did find quite abit of sludge at the bottom, near the pump and the oil is just starting to show signs of water migrating into it.the oil was moving quite well with only alittle bit of rostertailing (abt half inch high) in the pump base, flowing towards the left side port.
I saw a post which suggested using a torch to loosen the yoke, is that the only way?

I don't think that removing the top or bottom plates will help in figuring out what is wrong.
I just not sure where to start.
 
my opinion,if your lift works but wont lift a load,and you dont see a visible leak,its likely the bypass valve stuck,or broken. one way to check is to look for a large amount of swirling in oil.you can feel it bypassing,if your very carefull by placing your finger over end with it running,but i dont like putting my hands around moving parts.pump could just be worn bad enough it wont build pressure, but i would replace the bypass valve first if it were my own. grit and sludge gets in them sometimes and hangs them open.
 
(quoted from post at 10:45:04 09/27/12) my opinion,if your lift works but wont lift a load,and you dont see a visible leak,its likely the bypass valve stuck,or broken. one way to check is to look for a large amount of swirling in oil.you can feel it bypassing,if your very carefull by placing your finger over end with it running,but i dont like putting my hands around moving parts.pump could just be worn bad enough it wont build pressure, but i would replace the bypass valve first if it were my own. grit and sludge gets in them sometimes and hangs them open.

IMO Hobo's idea is the best technique for checking the relief valve, Insert a 2-3' length of clear vinyl tubing through one of the inspection ports and slip it over the end of the valve. It should be a snug fit on the end of the valve. Then try to lift a load on the 3pt. If the valve is opening you will see fluid accumulating in the tubing.

TOH
 
(quoted from post at 10:11:03 09/27/12) Hello,
I have a 42' 9n and at first the hydraulic lift wouldn't lift with any implement attached to it. Although, the lift would go up with nothing attached.
I removed the inspection plates, both of them, and no obvious leak was found. Then I checked the 'Spring, Hydraulic lift draft control' and has quite abit of slop when the lift was up. I tried to turn the yoke but as I have read, it's stuck solid to the plunger.
Then something changed, now the lift would not go down. So, I reached through the inspection port and felt for the control valve at the bottom of the forks. After some effort I located the valve or what felt like a 'T' and reattached it to the bottom of the fork. (I'm glad no one was watching as I was hugging the centercase, with one arm in either port) Well, the lift went down and then up and stayed up. Rather than beat my head on the differntial, I figured I would ask for some help.
I did find quite abit of sludge at the bottom, near the pump and the oil is just starting to show signs of water migrating into it.the oil was moving quite well with only alittle bit of rostertailing (abt half inch high) in the pump base, flowing towards the left side port.
I saw a post which suggested using a torch to loosen the yoke, is that the only way?

I don't think that removing the top or bottom plates will help in figuring out what is wrong.
I just not sure where to start.
eat is about the only reasonable approach, but before that battle,I would investigate a sticking control valve. It is a little difficult to determine, but once you understand the valve construction, you can probably determine if it moves freely or not. See picture. The small rod going into valve is not rigid to the valve 'spool', so just because the rod moves does not mean spool is moving. Probably need to drain oil level down to the spool in order to be able to make good assessment of movement. It may have pulled out of yoke again, if it is stuck. You can more or less get the big spring out of the picture by tying the yoke to the rear or wedging something between it & spring to force yoke to rear.
hyd_8N_EX_valve.jpg
 
Sorry abt the delay in getting back to you all. had to split the 9n and R&R the clutch and the main shaft seal. It took abit of doing but all is back together. Being that I didn"t have a decent floor jack for the front-end, I made a sled to slide the engine down after splitting. A couple of wedges kept it level and re-connecting took 15 minutes.
Now, as for the hydraulic problems,,,,the valves need rplcing and I have received all the neeeded gaskets and parts to complete the job. It does appear that the linkage is bent somewhere along the way as well. I have drained the fluid and need to inspect the linkage for proper angles or alignment.
AS I have read on previous posts, now is the time to clean the sludge out of the pump section. Is kerosene the preferred cleaner? I looked at other cleaning options at the auto parts store and opted for kerosene, just wanted to make sure I was getting the right cleaner. It"s not easy to locate kerosene at the local service station anymore! Heck it is hard to locate a "service station".

Thanks for your help. William
 
(quoted from post at 08:56:02 10/03/12) Sorry abt the delay in getting back to you all. had to split the 9n and R&R the clutch and the main shaft seal. It took abit of doing but all is back together. Being that I didn"t have a decent floor jack for the front-end, I made a sled to slide the engine down after splitting. A couple of wedges kept it level and re-connecting took 15 minutes.
Now, as for the hydraulic problems,,,,the valves need rplcing and I have received all the neeeded gaskets and parts to complete the job. It does appear that the linkage is bent somewhere along the way as well. I have drained the fluid and need to inspect the linkage for proper angles or alignment.
AS I have read on previous posts, now is the time to clean the sludge out of the pump section. Is kerosene the preferred cleaner? I looked at other cleaning options at the auto parts store and opted for kerosene, just wanted to make sure I was getting the right cleaner. It"s not easy to locate kerosene at the local service station anymore! Heck it is hard to locate a "service station".

Thanks for your help. William
iesel is cheaper, works as well, just stinks more.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top