No FEL Curl

Turkeyman · Oct 2, 2010

Our club has a 04 TC-35DA hydro with a 16 LA FEL. One of our members let the bucket blead down and jammed it into the ground so hard it blew one of the FEL hydo hoses for the bucket curl. We replaced the hose and put hydro fluid back in it but now the FEL will raise and lower but we cannot curl or uncurl the bucket. The bucket rams just blead down, but our 4 in 1 bucket works and so does the top and tilt.
Also for 610 hrs it never failed to start and now will not start. Could we have done something to hydro pump valve that is stopping it from starting now?

Any ideas?

Thanks

jinman · Oct 2, 2010

Try reseating the curl quick-connect fittings. Most of the time, it's a quick-connect that is not properly seated. This is especially true after a high pressure event like the bucket being jammed into the ground. That huge pressure spike probably popped out one of the quick connects.

Turkeyman · Oct 2, 2010

Thanks, we will check that tomorrow, any idea if the back pressure would cause it not to start/problems with the main hydro pump?

Thanks again

banjodunn · Oct 3, 2010

G'day if your 4 in 1 works then i doubt it will be your q/r's i think it is more likely that you have damaged the piston/seals in one or both of the tilt rams, the only other thing that i have had go wrong is a spool in the valve that changes from tilt to 4 in 1 has jammed ( i have actually seen them bent form shock loading like this

). You can take the solenoid off the valve and see if the spool is free to lift up/down with your fingers( engine off of course). With all your control levers in neutral you should have no hyd loading on the pump, when you say it won't start will it crank but not fire or not crank at all, sounds like it had a pretty good jolt may have jarred some wiring loose. Good luck with it

Jon

jinman · Oct 3, 2010

Jon, I think most electric diverters for 4-in-1 are plumbed in before the loader quick connects or the loader quick connects for curl would be one output of the diverter itself, but I could be wrong. Some 4-in-1s also may run off a rear remote; don't know for sure.

When the joystick is centered, there is no pressure relief for the hoses. The only system relief valve is blocked by the joystick valve. If you hit an obstruction, the hoses and joystick valve take the full shock. If the joystick is away from center (as in actively curling the bucket) then the system relief is in the loop and can provide relief, but a sudden shock might be felt by the main hydraulic pump. That should all be within the design spec of the pump's seals to handle. There should be no way to essentially deadhead the pump with full spike pressure from the loader.

With the joystick centered, there should be no pressure on the main pump whatsoever. The only way it would feel pressure is if the 3PH is at it's lower position with a load and the lift lever is raised. That would make the engine start under hydraulic load from the main pump. This could also be true of the remote valves or even the joystick if you move it to lift the loader while cranking over the engine. I don't think this would be the normal way someone would start the tractor. I think the 3PH would be lowered, all remotes centered, and joystick at center. In this position, only the power steering pump could possibly have any back pressure and that only if the steering wheel was being moved. If the engine will not turn over, I don't think it would be a hydraulic problem unless one of the pumps had a catastrophic mechanical failure and was locking up the drivegear.

J_J · Oct 3, 2010

Jim,

There is a possibility that if someone drove the bucket into the ground with great force, the mechanical linkage could provide enough force to cause a spike that could reflect back to the pump, and the relief valve might not be able to react fast enough. Something like a 5000 psi spike or greater, would be felt through the complete fluid path. The hoses would give some, but the pressure spike would go against the force of the pump.

banjodunn · Oct 3, 2010

G'day Jim i agree with what you say about there being no pressure relief with the joystick in neutral however as for the elec solenoid valve all the loaders i have fitted have them down on the boom with q/r's going to the 4/1 and switch between curl and bucket open/close i have seen them run of rear remotes but only in an old machine, i do not think the op has a problem with fluid delivery/pressure to the control valve as he states that he has full operation of raise/lower he has just lost curl function if he can tell me if the 4/1 open/close is working fine then i would tell him to pull off the curl cyl's and open them up to find a blown seal or piston IMHO. As for the not starting if it is an elec 4/1 i would check the fuses it is poss that the control was wired into the run circuit and if the valve has jammed the solenoid may have blown a fuse

Jon

jinman · Oct 4, 2010

J_J said:
Jim,

There is a possibility that if someone drove the bucket into the ground with great force, the mechanical linkage could provide enough force to cause a spike that could reflect back to the pump, and the relief valve might not be able to react fast enough. Something like a 5000 psi spike or greater, would be felt through the complete fluid path. The hoses would give some, but the pressure spike would go against the force of the pump.

I agree J_J if the joystick is not centered for the curl function. If the joystick is centered, it isolates the curl circuit from the rest of the hydraulic system. The curl circuit is essentially under hydraulic lock. There is no pressure relief for this condition and either hoses or cylinder seals will blow.

If the joystick is just slightly out of center and the bucket is moving, a sudden hit would cause a spike that will be felt by both the pump and the relief valve. The relief valve is about 10" below the joystick valve as an integral part of the diverter valve. The hydraulic pump is about 3-1/2' away through rigid piping to the front of the engine. Both would feel the spike and hopefully the relief valve would open and carry enough flow to mitigate the pressure spike.

If the joystick is in curl and the bucket is not curling (stalled), that's a sign that the relief valve is already open, Then, striking an object while moving forward would just cause a surge in flow through the valve. Since the pressure would already be at 2500, you would expect a surge in pressure and flow to be felt all the way back to the pump too.

Jon: You may be right about the plumbing and it sure could be bad cylinder seals. However, checking all quick-connects is such an easy thing to do on these tractors that a few minutes doing a check would not be hard to do. I'm thinking that on these tractors, most 3rd function diverters are installed near the loader posts instead of out front near the loader bucket where they are likely to be hard-plumbed. That's the way most grapple attachments are installed. On larger tractors, I see the 3rd function diverters mounted out on the boom rather than near the loader mounting posts.

Turkeyman · Oct 4, 2010

Thanks for all the suggestions. All the QC are fine and still lock in. Still not starting and it must have had major back pressure to blow a hole in 3500 psi curl hose. We need to check the fuse block but had trouble getting the cowling off to get to it. The WR Long 4 in 1 worked and had 2 separate lines running to it from I think a diverter under the hydro pedals not from the rear valves. If the valve was open to the curl rams I would think the oil would just pour out if the seals were crushed. It barly drips out of the o rings where the ram exit the cylinders.

Thanks for all the help.