Front-End Loader NewB needs help fixing joy stick issue with Zetor System 100 loader.

[chucker]

I'm new to tractors/hydraulics so I need some help. My joy stick operates the bucket just fine, it does not want to raise the boom. This problem has developed over time, when it started I could fidget with it and get it to work somewhat. Now my bucket is on the ground and I cant raise the boom. I opened the joystick up and I can see the piston/plunger for curling the bucket will go up and down from the neutral position. The boom piston / plunger will raise up but I cannot get it to go down past the neutral position.
It does not seem that it would be the cable because it will lift up, which drives the boom down. I found myself wanting to hit the piston with a hammer to make it go down so I decided it was time to ask for help. What is inside the hydraulic module, it must be a valve of some kind, is there likely something in the valve that would cause this?
The installation book I have says you can loosen the nuts on the bottom of the joy stick and adjust the cables, I wanted to remove the cable so I could tell for sure if the piston in the joystick could go down but when I try to adjust the cable there is no joint that spins so as I turn the cable with a wrench the whole cable turns, it cant turn enough to unthread from the bottom of the joystick. I'm a little afraid of the end with the valve since I've never been inside one, do I have to unhook the cable on that end first?
The tractor is a Zetor 3340, the original owner bought it in 2000 with the system 100 loader already installed. It might have been from a previous year but roughly a 2000 model
Any advice appreciated.
Thanks,
Chuck

 

[leonz]

What ever you do do not take it apart!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

What has happened most likely is the spool centering spring has broken and
has jammed in the spool.

There is no fix as they are all wear parts and you need to buy a new valve.

You could do either of two fixes:

1. replace it with a new valve from a Zetor dealer.

2. replace it with a conventional 2 spool valve from a reputable local supplier.

3. the best solution is a bit more pricey but it will never cause a problem for you again; by purchasing a 2 spool pilot operated valve from the hydraulic repair shop with the proper plumbing whether it is SAE or British Standard Pipe fittings with the blue dot O rings and compression washer used to seal and lock the fittings into position as they are installed.

The Pilot Operated Spool Valves require much less pressure to control them and the control valves can be replaced without a lot of work as they are mounted directly on the spool valves ports to control the oil flow at all times and have O rings to seal the oil flow or O ring flange gaskets.


You need to let us know if you have the British Standard Pipe thread on the valve block, the BSP fittings have an BSP O ring under a BSP washer that is compressed against the valve spool block to allow the easier installation of fittings and hose on the valve block.


The biggest problem with these valves is excess wear of the poppet valves and the springs as they use the least expensive parts to do this and using cables to control the valve spool compounds the problem as the force used to move the poppet valve is multiplied by a factor of 3 or more versus a simple open center flow spool valve set with a relief valve spool on the valve stack.

If you use the loader a lot you will want the 5 section pilot operated spool valves with a relief cartridge spool and they will last you hundreds of hours in real use so..................................................................................................................................

Decide how long you intend to keep the mule and then go from there as you will have to have a new mounting plate installed for the valve stack in any case as the mule and loader are at least 17 years old.


if you go to a repair shop do not let them convince you they can be rebuilt-no they cannot!!!!!!!!!!!!!!!!!!!!

 

[chucker]

OK, so first I need to take it apart and see what's what..................Then pay someone who thinks they know what they are doing to rebuild it.

Loved the way you make a point!!!

Thanks for taking time to help me out. I don't use the tractor or loader a lot so I will probably try to find a place to buy the original Zetor valve. I can probably manage replacing it myself.
Of course once I get the new valve installed and working I'll have to take the old one apart!
Thanks again.

 

[leonz]

Hello Chucker,

I only want to see you succeed and not fail. If you can find a commercial intertec or vickers hydraulics supplier all the better for you.

Its much safer to play with the dead one once you have the new one installed and running too haha.