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Subject: Hydraulic pump leak?

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JimWas    Posted 05-01-2018 at 17:58:30 [URL] [DELETE]        [Reply] [Email]  
  • Hydraulic pump leak?
  • My lift is weak and slow is I look inside and found this.
    Is it a leaking pressure relief valve?
    Thanks for all help.

    Tim Daley(MI)    Posted 05-02-2018 at 05:58:54 [URL] [DELETE]        [Reply] [Email]  
  • Re: Hydraulic pump leak?
  • OK, so you have a 2N Model. The 9N/2N Hydraulic Systems are different than the later 8N one. The early designs had DRAFT CONTROL only, the 8N introduced POSITION CONTROL switchable via the little handle on the RH side under the seat. Your video is SOP (Standard Operating Procedure) when pump is running. Repair procedure on the 9N/2N is similar to the 8N but one must use caution with the 9N/2N designs before pulling the top cover off. There is the control linkage 'wishbone bracket' which must be disconnected BEFORE the cover is removed otherwise severe damage will occur. I wrote an article on how to repair the 8N hydraulics on a budget, without removing the pump, and is available for FREE download in our HOW-TO's forum. You can first do the essential system test to determine if cylinder is bad, if lift holds a load up, and if not if leaking oil is evident at the cylinder. What is the current condition of oil? Is it a murky brown or clear/honey like shade? If oil is contaminated with water, then it will be murky brown and further investigation is required to determine if the pump is cracked, or water got into the system otherwise. Dropping the pump is a good idea for a rebuild since it probably has never been done. Get the I&T F-04 manual, the J&D video, and a 39-53 MPC, download a copy of my article, review the video, know what you are going to do before doing it, have the right tools, get a buddy to help, and don't buy any new parts yet -all the new parts can be bought at one time once you know what all will be needed. A new gasket set will be needed for sure, but some places offer new kits with all gaskets, new cylinder,new piston, O-Ring and wiper too. If the pump base isn’t cracked, it can still be used, with only old worn parts being installed. I would definitely replace the cylinder and piston regardless. The chambers need to be dismantled, cleaned, and parts replaced if needed. You'll be flushing the old oil out of the system, draining most before you start. A good cleaning will be done prior to reinstalling everything too. Since this project is pretty basic, not complicated at all, just time consuming, and goes easier when a buddy helps -lifting the top cover off is the biggest job. If the pump is dropped and rebuilt on a bench, it may as well be done right the first time, be sure to follow the manual and keep track of all the parts and how they go together. You want to be able to get another 30 years or more out the new system and not have to pull it more than once. To test for leaking cylinder, attaché a load like a blade or plow. Raise fully up and leave it up then shut down tractor. With inspection covers removed, take a good flashlight and look way up under the top cover/seat and observe the cylinder. Is there oil seeping/leaking out? Will the lift sustain the load UP without dropping within minutes or even hours? If seepage is evident and/or load drops, the cylinder is worn out and needs replacing. The original 9N, 2N, and 8N hydraulic cylinder piston used three steel rings for wipers/seals, which were notorious for wearing out cylinder walls. When the NAA (Jubilee) Model was released, the hydraulic system was revamped and now used a new piston that had a rubber O-Ring with a flat leather wiper/backup washer. This new piston will also work in the earlier systems as well. It is a better design and works well. Some fellas try to hone out the old cylinder but once grooves/scarring occurs, the O-Ring piston won’t stop the leaking altogether. I advise to just get a new cylinder and replace now. There is also a DIY video on 9N/2N hydraulic repair by J&D Productions -see LINK.

    My email is open if you want more help…

    Tim *PloughNman* Daley(MI)

    JMOR    Posted 05-01-2018 at 23:04:00 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Hydraulic pump leak?
  • That is simply the scotch yoke mechanism stirring the oil....completely normal.

    JimWas    Posted 05-01-2018 at 23:23:34 [URL] [DELETE]        [Reply] [Email]  
  • Re: Hydraulic pump leak?
  • What should I check for next? Hydraulic piston? Without a instrument it goes up slow and I can push it down. It was working fine until I started pulling on a few stumps.

    JMOR    Posted 05-02-2018 at 14:52:06 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Hydraulic pump leak?
  • these are the possible leak points. Another possibility is bent linkage which you can find by removing right side inspection port & observing and/or manually forcing linkage into the lift position.

    JimWas    Posted 05-02-2018 at 20:31:17 [URL] [DELETE]        [Reply] [Email]  
  • Re: Hydraulic pump leak?
  • Thank for all the help I found the wishbone brackett off. So I reconnected it and when I can get new hydraulic fluid I should be back in business. Anyone know why that would Popoff and how to stop that from happening? Thinking of wiring it or putting a zip tie on to keep it from happening again.

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