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Subject: 8n 3 point hitch

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Richard    Posted 04-06-2021 at 15:36:04 [URL] [DELETE]        [Reply] [Email]  
  • 8n 3 point hitch
  • Having trouble with my 3 point hitch. Went through it put a rebuilt pump on but still having the same problem The arms go up fine. hold any position. I installed a new piston and seals. Problem is after a short time they do not want to go down, I shut the tractor off and let it set for a couple of hours and they bleed down slowly and then start the tractor up and they again work fine for a while then stick in the up position again.

    Tim Daley(MI)    Posted 04-08-2021 at 06:26:26 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n 3 point hitch
  • There's more to the hydraulic system than just the pump. Sounds like you put a new piston in but used the old cylinder. That is why your system leaks down. Cylinder is worn and you should have replaced it when you had everything all apart. Now you'll have to pull top cover off and do it all over again. A proper hydraulic system will maintain a load UP for weeks, months. If cylinder is worn it will leak. You can do the leak test to verify via visual inspection thru side covers. Raise load UP and leave it. Look closely with a Mini-Mag up to the cylinder thru inspection covers and look for oil seeping down and out. OEM cylinder used 3 steel rings, like an engine piston, but the new NAA-530-B piston uses a rubber O-RING with a leather Wiper. It will also work fine/better on the 9N & 8N system. If you installed the NAA type, be sure the leather wiper is inserted correctly. The wiper goes behind the O-Ring, facing the open bore of the cylinder. SEE LINK for more info...

    Tim Daley(MI)

    Richard    Posted 04-08-2021 at 10:51:30 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8n 3 point hitch
  • Thank you for the info. I should have been more specific. I did replace the piston and rings (rubber/Leather) and the cylinder. When I meant bleed down it would be with the touch control in the down position. It was like the down position valve was opening just a small bit and not all the way as to function normal. The part that has me baffled is after setting for an hour or so the system would work prefect for a short time then all of a sudden not go down. When it was hung up I took the inspection cover off an reached in an bumped the control rod and it dropped immediately. So I am assuming it is in the touch control linkage Not certain if I have the position control spring adjusted right or if this has nothing to do with the problem. Also in the rebuild I replaced the badly worn linkage with less worn parts from another unit. Also replaced the cam pin but the cam had a bit of wear but didn't replace.

    Dead Eye Dave    Posted 04-08-2021 at 03:26:54 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n 3 point hitch
  • Good morning Richard. I have the same problem with my 8N. When using my heaviest equipment, a set of discs, once the tractor warms up they will sometimes stick in the raised position. I also do what you do.....I let the hydraulics bleed down and will hear a metallic click and it will work normally again. I also note that mine does not seem to be as quick to lock up if I do not put it in the full "up" position and if I raise and lower periodically. Not an answer to your problem I know but I am watching to see if anyone chimes in here with a solution. Dave

    Richard    Posted 04-08-2021 at 11:03:50 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8n 3 point hitch
  • Identical situation. Thank you, I thought I was going nuts. When it hung up the last time I took the inspection cover off and bumped the control arm and it dropped immediately. so it is either the linkage or the exhaust control valve. sticking. But since I wiggled the control arm it has been work normal all morning. One possibility is I don't have the position control vale spring tension right or one other possibility I replaced the cam pin but not the cam which had some wear causing the linkage not to work properly

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