Not grabbing

[boxersoft]

My 7341 has a front-end loader (Howard FX-2011) with a grab, operated by a joystick in the cab. When the jostick is moved left & right the grab tips up & down. If a button on the joystick is held at the same time, the grab opens and closes instead of tipping. But it's stopped opening and closing, and all it does is tip

Tracing the hoses and wiring , it seems like there's a valve that sends hydraulic oil round either the "tip" or the "open/close" circuit, and it's normally in the "tip" position. There's a rather heavy electrical component fitted to the valve. It has no moving parts, but a rod from the valve passes through a hole in it. I'm assuming it's a solenoid:

[/] [url=http://farm4.static.flickr.com/3074/3074532290_bba56b5374_b.jpg][/]

If I remove the electric plug from the 'solenoid' and put a meter across it, I get a voltage when the "open/close" button is pressed. It's only 3V, which surprised me (I thought it would be 12V), but at least something's happening so it's presumably not e.g. a blown fuse. My best guess so far is that the solenoid (if that's what it is) is blown.

Can anyone tell me (a) whether it is[/] a solenoid and (b) how I can test it? (I tried holding a screwdriver in the hole while the button was pressed, but there was no magnetism).

Alternatively, is there a good way to tell it the valve itself has seized? The disassembled photo shows the metal shaft that fits in the hole in the solenoid. I don't know if that is supposed to move to determine tilt vs. open (the oil "tide mark" suggests this might be the case), or if something is supposed to move inside it. I haven't tried forcing it for fear of damaging something.

SteveR.

 

[ixer0]

Hi

The voltage at the solenoid should be 12 Volts. Check your wiring connections. If you have a connector where the quick release couplings are, try there first.

Mike

 

[boxersoft]

Thanks, I'll check it out and report back.

I took the reading from the connector that plugs onto the solenoid (thanks for confirming that's what it is, by the way). It's the one that can be seen in the first picture.

 

[treaney]

1. Disconnect the electrical connector on the solenoid (which comes from the open/close switch).
2. Run a wire from battery positive +12V directly to the solenoid. Touch the contacts briefly - you should hear a clunk.
3. Test that you can now open/close when power is applied to the solenoid.

 

[Renze]

Your loader hasnt cracked around the torque tube yet ?
Mine (Veto FX 12) was when i bought it, and i was told they all do. I did some major reinforcement, (welding 50x10mm S355 quality flatbar on top and bottom flange of the brake pressed profile, increasing its theoretical strength by 70%) and now the only problem is keeping the console gussets from cracking... I need to adress that problem before muck spreading season starts again, from february 1st...

 

[boxersoft]

OK, I got my wife to try operating the open/close button while I was checking the voltage. It was about 3V, but it kept dropping - it might actually have been switching polarity because the needle on the meter seemed to be showing less than zero. She was still holding the button pressed while this was happening, and she reported that she could hear something in the joystick clicking (presumably a relay). I opened the joystick but I couldn't see any obvious faults on the circuit board - it only contains the two buttons and a couple of components that look like relays.

I tried connecting 12V directly to the solenoid but that only gave a very slight >click< rather than a convincing >CLUNK<. I haven't yet tried operating the grab while it's connected this way, I'll have a go when I get a chance.

By the way, do e-mail notifications work on this forum? I don't seem to receive them for some reason.

 

[boxersoft]

Checked today. The grab does[/] open and close if I hot-wire a 12V supply to the solenoid while an assistant operates the joystick. I guess that puts both the solenoid and the valve in the clear and points the finger at either the switch/relay circuitry or the wiring somewhere along the line.

The switch circuitry seems to consist of two buttons and two relays, but there are only four wires at the circuit board - black and brown, and blue and yellow. I think the black/brown are a 12V supply pair, and the blue/yellow a switched live. I expected to have two switched pairs so the buttons could control separate things, but apparently not. Confused

 

[boxersoft]

Your loader hasnt cracked around the torque tube yet ?

Dunno - I haven't noticed anything, but I'm a newbie so I might not notice until something falls off. Which bit is the torque tube, and would a crack be obvious to an untrained eye?

 

[Renze]

Its the tube on which that solenoid valve is mounted: it connects both loader booms together.

They usually crack on the top side, in the edges. Thats where a tension peak occurs. On the lower end, the torque tube is round so forces are lead in evenly over the boom.

 

[boxersoft]

Turned out to be a bad earth. All the meter checks seemed to indicate that everything was fine, but the negative supply to the joystick (from a bolt in the console) was failing on load (i.e. when the button was pressed). A pig of a fault to trace, but at least I know a bit more about how it all works now. Thanks for the help , folks.

When putting it all back together, there's a fair bit of freedom with the position of the joystick. On my first attempt I found that it didn't seem to pull all the way back. The loader would raise fully, but quite slowly. Any tips on getting the positioning right, or is it just a case of trial & error?

Renze: Thanks for explaining what the torque tube is, I'll try to keep an eye on it. If it fails, is it likely to do so spectacuraly and dangerously, or is it more likely to fail to lift one day or something?

 

[Renze]

Renze: Thanks for explaining what the torque tube is, I'll try to keep an eye on it. If it fails, is it likely to do so spectacuraly and dangerously, or is it more likely to fail to lift one day or something?

I dont know, i didnt wait for it...

As soon as you see movement around the cracks when lifting/dumping, you're not 10 cycles away from falling apart.
But i guess the cracks (and the rust water leaving traces over the paint) will tell beforehand, and you can keep an eye on it.

Maybe the later model (like you have) is beefed up a bit ?