42' 9n hydraulic lift problems

[William S]

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.
 

[jackinok]

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.
 

[TheOldHokie]

[JMOR]

[William S]

Thank You all for the help. I see my day is set for me and I will get back to you with the results.
 

[William S]

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
 

[JMOR]