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Subject: 8n hydraulic problem

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Mitchell    Posted 05-25-2020 at 14:20:25 [URL] [DELETE]        [Reply] [Email]  
  • 8n hydraulic problem
  • The lift arms raise no matter what position the lift handle is in . I recently bought the tractor and haven't replaced the hydraulic fluid it is dirty and has moisture in it. The system is not strong enough to raise the implement and bleeds down after sitting awhile. Besides dirty fluid what other problems could there be?Thanks

    Tim Daley(MI)    Posted 05-25-2020 at 15:38:28 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n hydraulic problem
  • You have a severely worn hydraulic system and it's time for a rebuild. Simply draining the old oil and replacing with new oil isn't going to fix anything. You describe signs that the cylinder is worn amongst other issues. We have our HOW-TO's forum (note rd menu bar at top of home page) with many DIY and self-help projects. One is listed below -click on the LINK. If you've never pulled the top cover, it would be wise to get the Essential Manuals and the documents and read first. The cylinder is bolted to the underside of the top cover with four bolts under the seat area. If you remove them BEFORE you pull the top cover you will do extensive damage to the unit and have a massive project getting it off then. The hydraulic system repair isn't that big of a job, but is very time consuming. Best to have a helper too. The OEM N-Series hydraulic cylinder used a 3-steel ring piston. This was replaced with the NAA-530-A piston with a rubber O-Ring. It is a better design and will also work on the 9N,2N, and 8N as well. You will need a new cylinder (don't try to reuse old one); a new piston; a gasket kit; a new safety relief valve; and possibly some pump parts. Don't buy anything til you get the pump off and on your bench. You are going to want to inspect the aluminum pump base and if cracked will need to replace it. New parts can be found at trusty sites like Dennis Carpenter and Just8ns. READ all the manuals first.


    Tim Daley(MI)

    Mitchell    Posted 05-25-2020 at 17:47:38 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8n hydraulic problem
  • Thank you for the information...I misspoke earlier when I said that the arms bleed down ...they can be pushed down with relative ease though...it's still probably a good idea to go ahead and rebuild the pump and get it over with

    Tim Daley(MI)    Posted 05-27-2020 at 06:21:25 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n hydraulic problem
  • Mitch-
    Lift arms dropping on their own or with a little help -it doesn't matter. A properly operating hydraulic system will sustain the lift arms fully UP with or without a load for week, even months. You've already determined there is definite cylinder issue so no need to do the leak test. As I stated in my first post, you should get the Essential Manuals and read all there is before attempting to pull the top cover and investigate further. The OEM 8N Operatorís Manual has a Chapter on the hydraulic system. The CLYMER/I&T FO-04 Manual has an excellent chapter on removal, rebuilding, reinstalling the system. I might also suggest at this time you consider rebuilding the PTO shaft seal and bearing. When you go to ordering parts, you can get the whole gasket kit (p/n 9N-500K), cylinder (p/n 9N-510-D ), piston (p/n NAA-530-B ), O-Ring
    (p/n NAA-533-A), and backup wiper/washer (NAA-473-A) - see LINK.


    Tim Daley(MI)

    TheOldHokie    Posted 05-26-2020 at 06:00:21 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n hydraulic problem
  • If you can push the arms down you have a leak somewhere in the lift circuit. Most common source is the lift cylinder - much easier and cheaper than the pump. Another possibility is a sticky/dirty control valve or pressure safety valve in the base of the pump. I'd do some basic internal inspection including a hard look at both before I jumped into a full overhaul of the pump.


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