My John Deere 790 grapple installation

   / My John Deere 790 grapple installation #1  

skippythedog

New member
Joined
Oct 20, 2007
Messages
3
I have a 2005 JD790 w/ a 419 loader and Woods backhoe installed. I needed some way to clean up processed branches after a logging operation on 40 acres and began looking for grapples. I perused and digested everything I could find on the subject and decided on this approach:
I selected a 48" Wildcat from Mid-State in NC, $1000 shipped to Seattle. The 48" weighs 420# compared to 520# for their 66" single cylinder. I chose their design primarily because of their 3rd tooth on the upper claw which meant I could potentially pick up some smaller rocks etc. I debated on their lower tooth design as I was concerned that the wider "shark tooth" might make for too much friction while scraping roots/brush. As it turned out, it was a good choice. The load seems perfect. It may have been too much w/ the 66" grapple on this tractor. (Most shops will recommend a 60" or 66" grapple for a 30hp tractor).
Because of the 790s "detuned" hydraulics @ 2050psi, I decided the added 100# payload would be substantial. Also, I believe that the shorter sides would mean less leverage force by longer logs etc. that could potentially tweak the loader arms. The grapple pins right on to the JD quick release plate on my 419 loader.
There's only really 2 ways to add a "third function," hard plumb some lines to a valve body that you mount in some funky place somewhere near your joystick or use an electric diverter valve w/ a button zip tied to your joystick. You could get creative and get an integrated knob/ button from various sources but you still have to snake a wire up your joystick. I chose the kit from Rankin in Yakima, WA ($425 shipped). You can find them a bit cheaper but virtually no one stocks them. I was in a hurry.
The Rankin kit is well made w/ a quality valve (according to my hydraulics guy) and has a very nice, sturdy rubber cord and weatherproof switch.
I found an awesome hydraulic shop in Tacoma, Epic Industrial. Dave the owner, took charge of the project and made some very nice design changes, consulting with me on everything. Dave added shields to the grapple to protect the cylinder and hoses. One is a mesh that I can see through.
The typical grapple installations w/ the 5 foot hoses flopping around, held w/ bungee cords and springs seemed cheesey. I also wanted bulkead fittings to give me something firm to push against when connecting. Dave installed 2 bulkeads and 2 different sets of hoses w/ rotating fittings resulting in a very clean installation w/ minimal hose movement/wear. The hard lines look factory and the diverter was mounted to the masthead on the left side. It's covered w/ a steel shield which mounts to a couple of the bosses on the diverter valve.
I installed one of the JD shim kits (AM875169) in the pressure relief valve body which resulted in a pressure increase from 2050psi to a peak of 2650psi. It produces 2400psi at idle.
This implement is the best thing since sliced bread for the typical brush clearing jobs, fire tending etc. I'm ecstatic about it as the grapple nicely bridges the ability between a tractor and small excavator w/ a thumb for clearing ability.
The round bar near the leading edge of the grapple keeps the implement from digging in as a bucket would and I can scrape a clean swath into the brush for about 15-20 yards in first gear high range w/ no undue strain on the tractor or loading arms. Previously I could only scrape (backwards) about 8-10 feet of brush w/ my bucket while dragging up a bunch of soil with it. Any roots (sagebrush!) that are missed by passing between the teeth can be taken out on a subsequent pass at an intersecting angle....Great investment and now my most used implement.
grapple 028.jpggrapple 034.jpggrapple 033.jpggrapple 030.jpg
 

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   / My John Deere 790 grapple installation #2  
Nice job! That really turned out fantastic!
 
   / My John Deere 790 grapple installation #3  
Nice clean install.
I would add tie wraps on the hose protectors on the single hoses to the grapple cylinder. To keep them from sliding and keep debre out.
 
   / My John Deere 790 grapple installation #4  
looks great and they are handy
 
   / My John Deere 790 grapple installation #5  
Thanks for the novel...
handsome dog...!
 
   / My John Deere 790 grapple installation #6  
A very nice install, Well thought out and well documented.:thumbsup:

James K0UA
 
   / My John Deere 790 grapple installation #7  
Good job and clean looking tractor.
 
   / My John Deere 790 grapple installation #8  
Well done job with the grapple... and I am envious of your backhoe to!
 
   / My John Deere 790 grapple installation #9  
Nice. Did Wildkat send the grapple painted green?
 
   / My John Deere 790 grapple installation #10  
Looks good
 
 
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