TYM 474 3rd function/grapple malfunction after 50-hour service

[Zakleeright]

Hi all,
Been loving the TYM 474 I bought in 2024 (first tractor), and reached 50 hours, did the service myself...easy, no issues, tractor worked great after that as always, but I wasn't using the grapple. The grapple was not attached when I did the fluid drain/refill operations.
Last weekend, finally attached the grapple, and only got about 4-5" of travel. My neighbor "knew a guy" who popped over and started using a 11/16" wrench to loosen the connection where hose meets fitting/junction point while I operated the grapple. He eventually got both sides to fully open quickly, as normal. But the grapple closes very slowly and with little force.
Someone else is telling me that any air in the hydraulic lines for my kind of tractor will self-purge if I bring the FEL up about half way, hold the open button down for 15 seconds, then closed button for 15 seconds, and repeat 20 times. Of course I will try this after work today, but I'm not sure either of my sources are experts. (although the self purging thing seems to make sense).
Of course, looking for answers on how to really purge the air in the lines (which seems to be the case as far as I can tell) and what might I have done differently or better to prevent this issue from happening in the first place.I should also mention that when I initially connected the hydraulic QDs for the third function, one of them may not have been in all the way (tho it didn't pop off). When I reconnected it, it seemed to seat better, but this had no effect. Maybe I cause the issue from a "90% connected QD" if that's even possible?
Thanks!

 

[oldnslo]

Has the 3rd function worked in the past or is this first time you have tried to use it?
Air will usually not affect operating speed as much as making system spongy or jerky. Yes it will self bleed after a few cycles.

Is your grapple a true 3rd function that operates independent of joystick or does it work with joy stick curl dump circuit.

If independent confirm the valve is shifting fully both ways. Some valves have manual override push buttons. If yours has this feature try operating them?

If quick disconnect ends are the same try swapping them so open is now close to see if operates differently. Quick disconnects can cause the problem you are experiencing.

 

[Zakleeright]

Thanks oldnslo!
3rd function always worked great until after the 50-hour service. it is not a true 3rd function, in that I cannot operate the grapple grip and FEL at same time. (Two buttons on joystick operate an electric solenoid or relay(strong "click" heard for both open and close..) When the grapple is not on the tractor, I always cover grapple and tractor side QD's with plugs...they look as new inside/out, not that they couldn't have failed in some odd way. The QDs are "keyed" male/female, so not possible to connect them wrong, nor reverse them.

 

[oldnslo]

Did you remove the loader when you did the 50 hr service?

If it worked and now doesn’t would point towards a quick disconnect not fully seated or the valve not shifting fully. With tractor at idle try operating the grapple and pay close attention to both hoses going from quick disconnects to the grapple. Do they both stiffen and swell when grapple tries to move or does neither hose stiffen.

On the valve does it have round pins in the center of the tube assembly the coil fits on? If yes take a small screw driver or some tool and try pushing on them. They could be manual overrides so you can manually shift the valve.

 

[Zakleeright]

I've never removed the loader. I simply disconnected the grapple, drained fluids, replaced filters, hit the zircs, tested for leaks, all good using the tractor w/three point hitch, forks, bucket - stuff that don't use 3rd function. Then I put the grapple on, and the limited movement. I can see one of the 3rd function hydraulic lines stiffen when I open, the other stiffen when I close. I just did about 30 minutes of opening/closing the grapple, after it sat for a few days (had family stuff out of town, just got back). Grapple opens as normal 1-2-3-bonk...its open. At first it took 20 seconds for both sides to close. After about 15 minutes, it closed in about 12 seconds (always one side, then the other). Then I started driving around while doing it...no noticeable change. Then I started moving the loader up/down. When loader near top of range, it closed much more slowly. Then I started tilting the grapple up/down. When the grapple is tilted downward, regardless of loader height, the grapple closed quicker...aboout 8 seconds. When tilted up, at least double that. This was the big difference I noticed. Grapple tilted up or down, no effect on opening the grapple. Grapple tilted down, grapple closes almost as fast as normal, Grapple tilted up, grapple closed very slowly. so slowly that I lose patience and tilt the grapple down. As soon as I start tilting downward, grapple begins to close.

 

[GrandpaSmurf825]

Good advice from oldnslo to you. The fact it's changing how it works when you raise or lower the loader is odd. Double check your quick connects on the grapple. It sounds like something is up there, if changing the grapple tilt angle impacts the operation. When you first said the neighbors friend helped by loosening fittings I thought it was going to be a lock valve that had line pressure on the other side that was greater than your tractor system operates at. It might have been part of it. A quick connect can look fine and still not be flowing oil properly. Maybe someone can watch or operate the grapple while you watch as well. Maybe take some photos of the hydraulic coupling attachment point as well as the 3rd function valve. Also the type couplers it uses. Ball, or plunger style. They need to be the same on both male and female or that can be a problem. As oldnslo said it isn't likely air in the system. First of all how did it get there if you never had hoses apart other than at the quick connects? It almost has to be a problem with the quick connects and moving the grapple is moving the connection enough to affect it.