understanding my front loader hydraulics

[lapioche]

I bought a front loader (used) for my Zetor 7245. I am trying to understand how it functions as the system is not straightforward. There are four valves, three of one type and a fourth that's different, that I would like to understand what they are for. I drew a (crude) schematics based on observation (the direction of the lines is my guess, and of course they reverse).

If someone can tell me what are the valves in the system and what they do, I'd greatly appreciate.

 

[rScotty]

Not enough info. What tractor did the loader come from? Is the loader also off of an open center type of hydraulic system?

Does T mean "Tee"?

Where are the valves? I assume they are feeding the colored inputs? But that would only require two. How are the other valves connected?

Do you know what the Hydacs do? Do they have any markings? It's impossible for me to be sure what they are... could be relief valves, flow control or accumulators....or ? Do they have a pneumatic fitting?

 

[lapioche]

1. I don't know what tractor it comes from but the tractor connection is designed for Zetor. So I assume it was a zetor, and by the size of it, something around 70-80hp.
2. T indeed means Tee. These are just fittings. I marked them so I have an easy time looking at the system with the diagram but functionally they aren't necessary.
3. all the valves are attached at different places on the inside of the loader, along the arms and the connecting bar.
4. I don't know what the HYDACs do. The port letters are marked and noted on the schematics. They have no pneumatic fittings but there's an unused small port marked M. They look like relief valves but I'm trying to understand the logic of how they are connected.

 

[CliffordK]

How about some photos of the actual parts in question.

You could have a third function control such as a grapple.

Are there any wires going to the hydraulic controls? Self leveling?

 

[Harry in Ky]

Post some photos of what you have. If anyone can make any sense of your description they're far smarter than I am.

Could be your best bet might be to just invest in a new loader valve and be done with it.

 

[Leejohn]

Maybe this well help.

 

[ptsg]

Can you share a picture of the loader? I suspect it has self leveling, either mechanical or hydraulic, therefore it will have at least one extra relief valve mounted in the loader.

It can also have valves for loader suspension. Then again, we need some pictures.

 

[lapioche]

thanks for all of you responding. here's some photos. you can see the three HYDAC units with three connections as well as the single other valve with four connections.

 

[redman135]

In photos #2 and #3 I have seen similar looking valves on diggers. Thier job is to prevent the digger boom free falling if a hydraulic hose has a blowout. Possibly these do the same job. ?
Can any hydraulics people comment?

 

[ptsg]

The two valves mounted on the curl cylinders look like regen valves to me, to prevent the floppy bucket when fully dumping a load.

The other one may be the relief valve because of the self leveling linkage.