[Firemedic1198]

Just finished putting together my third function hydraulics for my grapple bucket. Using the rear SCV to run it. Used garden hose to figure out lengths for hoses. Local NAPA made them for me. Both rears have a 90 degree to a male ag fitting. At the side of the tractor where the loader hydraulics can be disconnected to remove it, I used a male and female ag fittings so I can split the third function off as well. The thing I haven’t seen anyone else do when they use the rear SCV is to take advantage of the routing of the lines through the loader frame (520M). There were 4 running through already and it had room in the clamping bracket for two more. Made it look much cleaner than zip tying the lines to the frame. Had to remove the plastic shrouds on the loader crossbrace to access the pass-through but wasn’t too difficult. I bought a piece of aluminum angle, painted it, and drilled holes to mate it to the existing bracket on the loader. Had some struggles finding the exact bulkhead fittings I wanted and had to buy them with the hydraulic fittings on them from Summit. I opted to go with skidsteer style because that’s what’s already on my grapple. Everything is NPT except the fittings on the loader. Had to get JIC skidsteer fittings with JIC bulkhead from Summit then got a 90 degree JIC to NPT from OneHydraulics. Got all the ag fittings from Summit as well. Used Loctite 545 on all the fittings. True test will be in a couple days when I attach everything and pressurize it. This is my first foray into hydraulics. Crossing my fingers for no leaks!

 

[Zebrafive]

One more thing you could do; add zip ties to the hoses that connect to your rear SCV. One zip tie on the top hose to top quick coupler, and two zip ties on the bottom hose to bottom quick coupler.
I do this with the 6 hoses for my rear blade. I use colored zip ties to match the colors of the dust caps on my rear SCVs. It's intuitive for me to remember one zip tie = the top/upper quick coupler, and two zip ties = the bottom/lower quick coupler. IIRC my dust caps are green, brown and blue. A different model JD tractor has colored rings for the SCV lever's knobs. I added those to my tractor too.

LMK if you want pictures.

 

[Firemedic1198]

One more thing you could do; add zip ties to the hoses that connect to your rear SCV. One zip tie on the top hose to top quick coupler, and two zip ties on the bottom hose to bottom quick coupler.
I do this with the 6 hoses for my rear blade. I use colored zip ties to match the colors of the dust caps on my rear SCVs. It's intuitive for me to remember one zip tie = the top/upper quick coupler, and two zip ties = the bottom/lower quick coupler. IIRC my dust caps are green, brown and blue. A different model JD tractor has colored rings for the SCV lever's knobs. I added those to my tractor too.

LMK if you want pictures.

That’s a great tip! I will do that. I tested it today and - no leaks! By dumb luck I attached the hoses the way I wanted it to work (lever back = jaws open, forward = closed). I’ll put some zip ties on the fittings so I can get it right in the future. I will have to remove them on occasion for my post pounder and mower hydraulics since I only have one rear SCV.

 

[Zebrafive]

That's intuitive, the way you have the SCV lever operate your grapple. Mine is the same way on my JD 2030. I am also using a rear SCV.
My SCV has detents in both directions. The detents let the grapple open or close without me having to hold the lever. The lever returns to center/neutral when the grapple cylinders reach the end of their travel.