What is going on with the (hydraulic) quick connect fittings on my Model 70 loader???

kebo · May 20, 2017

Sorry for the really long post here, but thought the details might be pertinent...

This first started about 2 weeks ago, I removed the loader to mow the yard, because it's easier to maneuver with it off, and it lowers the chance of hitting something making sharp turns. So, after I got through cutting grass, I went to put the loader back on and couldn't get the quick connect fittings to hook up again. Pushed the collar back, shove the male fitting in (from the loader) and it would almost get to the point where the bearings would drop into the groove, but then it just stops and won't go that extra little bit to lock in. It did this on at least two of the fittings, but I can't remember now if it was doing that on all four fittings.

So, I messed around and tried all sorts of stuff, like working the SCV (joystick) all 4 directions. I'm not even sure that does anything with the hoses disconnected from the tractor, but I just thought it might relieve any residual pressure on the tractor side. I checked the pins recessed in the female fittings on the hard lines on the tractor, the pin in each could be pushed in easily with a small flat tip punch, and some fluid would seep out. I kept thinking the problem was with the fittings from the loader, like the cylinders were in a bind and there was too much pressure for the pin on the male end to push it in by hand. I wound up taking a wrench and loosening the hose on one cylinder until some fluid seeped out, and I finally managed to get them all four hooked up again. When I had unhooked it, I did have the lift arms fully retracted, so the cylinders were at full extension. Maybe the two lift cylinders were in a bind??

So today, I rinsed and repeated and got the same results. Removed the loader, cut grass, and went to hook up the loader again. COULD NOT GET THE HOSES TO RECONNECT.

However, this time I made sure before I disconnected the hoses, that the lift cylinders were not FULLY extended. I tried all the other things I tried the last time with no success (except I did NOT loosen a hose on the cylinder this time). I'm guessing that these fittings would come within about .060" or .070" of the ball bearings dropping into the groove so the collar can slip forward and lock them in place.

Finally, after a full hour of dicking around with it trying different things, I finally got the two outboard fittings to lock in place. I didn't know what function these two lines controlled at the time (and the flexible lines are enclosed in a sheath so you can't follow them easily), but I was HOPING and PRAYING it would be for the lift arms to let me retract it so I could at least get the loader hooked back onto the tractor and latch it in place. Prayers answered! The two outboard hard lines control the cylinders for the loader lifting arms, so I was able to get it hooked up to the tractor. However, the two fittings for the curl function still refused to cooperate, and so I left them unhooked. Here's a clue though... Once I got the two outboard fittings to hook up, I disconnected one of them, and then tried hooking one from the curl cylinder into it, just to see if it would lock in place. It would NOT lock in! Put the line from the loader cylinder back in, and it WOULD lock in place. In my mind, that proves the "problem" is on the loader side, not the tractor side.

I am not sure if I really did anything that let those two outboard lines finally reconnect, but if anything, it may be that "time" is what helped it. I now have a theory that it takes some time for the cylinder pressures to leak down just enough to let me lock the fittings in place. Does that sound plausible?

Keep in mind, this tractor is 60 miles from me now, so I can't just run outside and try any suggestions now. It will be next Friday before I am back up there again. I am hoping that the other two lines will simply snap into place when I get there. Will keep you posted on that. I do know one thing, if they do snap in place, I won't be taking that loader off anytime soon! I can't be spending an hour every time just trying to get 4 hoses reconnected.
Also, I have been removing the loader now for a year, or maybe two years, when I cut grass. This just now started happening. Do those little tips in center of the quick attach fittings wear down?? That was the only thing I could think that might be a problem, because they were so close to locking in place.

Your thoughts???

Rustyiron · May 20, 2017

I'm not sure on how many psi of built up pressure (from temp change or just gravity on the cyls) it takes to make the couplings impossible to work, but I think it's only a couple. When you have to, just loosen the fitting on the loader side that will not go on to relieve the pressure. It's an oily mess so have some rags on hand. I can't explain why this hasn't happened in the past other than maybe just dumb luck. You might be able to relieve the pressure on the male loader fittings by tapping the protruding tip up against something hard, too much pressure and this may not work. This won't work with female fittings.
If you are able to, remove the loader while everything is at operating temps.and park it in the shade. Reconnect while the loader is cool and not in the sun.

DLTTrekkers · May 21, 2017

Before disconnecting ....shut-off engine and play with the levers to reliese all pressure from all the hydr lines ...then dissconnect....before connecting....the same....remember that imp will settle itself in the ground ...so release all hosepressure before atemting to hoke-up.

boggen · May 21, 2017

cold tractor has yet to be started = cold hydraulic rubber hose lines
warm tractor and has been running = warm hydraulic rubber hose lines that have expanded some.

taking loader off while warm = rubber hoses contracting some as it cools down. result = pressure build up.
taking loader off while tractor is still cold just barely started to move and position to unhook loader = rubber hoses still contracted and yet to expand from heat.

as other noted. once you get loader in given spot to unhook, shut down tractor, and run through the joystick/levers for FEL. to reduce pressure. before unhooking hydraulic lines.

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if you are placing FEL and bucket in an under pressure state when hooking backup. there might be an issue if you creating your own "pressure" that you are fighting against.

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if you gotta do it. get yourself 2 quick disconnects and 2 valves. and toss 1 set onto bucket cylinder hose, and toss the other set on FEL cylinder hose. open valve to let oil out / pressure off system. then remove disconnect and valve, and hook to tractor.

mrmikey · May 21, 2017

Piece of 1/2 dia wood dowel or a clean stick 6" long or so, rag and something solid. Put the dowel in the fitting, wrap a rag loosely around it and give it a rap on something solid to push the ball in. On the male one, rag around it and give it a rap on the end. It doesn't take much sunlight on black hoses to generate enough pressure to lock up a fitting...........Mike

ericm979 · May 21, 2017

There are ag style couplers that allow connect under pressure, like Pioneer 8200s.

scdeerslayer · May 22, 2017

The problem is likely the sun heating up the oil and building a little pressure. Try taking the loader off in the shade or under a shed.

kebo · May 24, 2017

DLTTrekkers said:
Before disconnecting ....shut-off engine and play with the levers to reliese all pressure from all the hydr lines ...then dissconnect....before connecting....the same....remember that imp will settle itself in the ground ...so release all hosepressure before atemting to hoke-up.

Sorry for not getting back sooner... this is something I always do (work the SCV in all 4 directions), so I won't get a face full of hyd fluid. It's on the instruction label stuck to the loader mast that tells you how to dismount/mount the FEL.

kebo · May 24, 2017

boggen said:
cold tractor has yet to be started = cold hydraulic rubber hose lines
warm tractor and has been running = warm hydraulic rubber hose lines that have expanded some.

taking loader off while warm = rubber hoses contracting some as it cools down. result = pressure build up.
taking loader off while tractor is still cold just barely started to move and position to unhook loader = rubber hoses still contracted and yet to expand from heat.

as other noted. once you get loader in given spot to unhook, shut down tractor, and run through the joystick/levers for FEL. to reduce pressure. before unhooking hydraulic lines.

=========
if you are placing FEL and bucket in an under pressure state when hooking backup. there might be an issue if you creating your own "pressure" that you are fighting against.

============
if you gotta do it. get yourself 2 quick disconnects and 2 valves. and toss 1 set onto bucket cylinder hose, and toss the other set on FEL cylinder hose. open valve to let oil out / pressure off system. then remove disconnect and valve, and hook to tractor.

I will say that both times when I disconnected the loader, the fluid probably didn't have much time to heat up, as I disconnected it right away after cranking it up and deciding where to park the loader at. Maybe that is the problem?

kebo · May 24, 2017

scdeerslayer said:
The problem is likely the sun heating up the oil and building a little pressure. Try taking the loader off in the shade or under a shed.

I will also add that the first time it happened, I had parked the FEL under the shed where I park my tractor. The second time, though, it was parked out in direct sunlight for several hours. I know well, it was 93 deg and I thought I was gonna have a heatstroke while trying to get four stupid hoses reconnected!

I will be back up there Saturday and I'll see if they will reconnect. I will report back then. Thanks for the replies!