Rear hitch hydraulics with front loader help

   / Rear hitch hydraulics with front loader help #11  
Usually those block off plat or caps aren't really block off plates.

Its a place to add functions like the loader or a remote valve.

With the original plate on it....it would simply connect the two ports....not block them off. One port would be high pressure oil coming from pump, the other would be return (but not to tank) rather it is return to the 3ph control inlet.

So with no attachments....the 3ph plumbing is mostly internal. So think of that "cap" as a hydraulic hose couples right there that is feeding the 3ph. And changing the "cap" is like uncoupling the 3ph feed, and allowing you to feed something else like your loader first....and then tying the loader back in to feed the 3ph.

It's hard to understand just where all the hoses are going and routes without actually laying eyes on it and tracing the circuits in person.

But it your loader valve indeed has 7 hoses.....you DO have a P (supply);a T and a PB.

The supply is probably coming from that cap. Your loader works fine.

But as I said....you have two ways for oil to exit your loader valve.
1. It exits the PB port when the loader isn't being cycled.
2. It exits the T port when the loader is cycled.

You have the T port going back to the 3ph feed. Which is why it only works when you cycle the loader.

Since the original owner had a backhoe and never used the 3ph....dumping oil back to tank through the open center 3ph valve when using the loader was ok. And he used the PB loader port to go to the remote valve.

I don't think you posted pictures of the remote valve plumbing.

Ideally it will have 3 hoses to connect it. It should have it's supply coming from the PB of the loader....and it shall have its own PB port to feed the 3PH as well as a second tank or return.

The only things that can be TEEd together are the tank lines.

In an open center system you can never tee a P or PB line.

Right now.....if you want to omit that remote valve just to get working....follow the T hose coming off the loader valve and unhook it where it attaches to that "cap". Find a new place to dump it back to the hydraulic/transmission case. And take the hose currently going to the remote valve and put it on that "cap" where you just unhooked the tank line from
 
   / Rear hitch hydraulics with front loader help #12  
Might add that the danger in using a T port to feed a P port is that the valve with the T port may not have been designed to withstand system pressure in the housing and could "explode" if downstream pressure is excessive.

That excessive pressure could be caused, in this case, by an unusually heavy load on the 3PH.
 
   / Rear hitch hydraulics with front loader help #13  
Yeh, all still works fine. Backhoe is only connected to frame and PTO, not into the tractor hydraulics. I've been reading @chrismac long post and it looks like he had the same triangular block under the seat. But then it also fed another set of spool valves under the seat too

Hi, I see your having hydraulic issues, the 2 ports on top of your hydraulic block under the seat need to be plumbed in completing a feed loop if that makes sense, you maybe have seen that on my post, this then goes on and feeds the 3 point linkage, the centre port which is currently blocked on your triangular block is for a free flow return to the tank.


hope that works if not I will fix the link later.

Chris
 
   / Rear hitch hydraulics with front loader help
  • Thread Starter
#14  
Thanks Chris, I was hoping you might chime in seeing your experience with the same tractor!

So the issue I have is the loader valve doesn't appear to have a power beyond valve - just a third joystick valve that goes to a point at the rear

Unfortunately, I don't have a rear spool valve like yours under the seat :-( I doubt I'd be able to find one of them these days but correct me if you know where I might look, especially if you know the part number.

Here's a pic under my seat

IMG20220313155536.jpg


So I feel like my options are:

Live without the 3ph (I could at least feed the T port to the right middle hole from the loader)

Somehow source one of those under seat valves

Or, replace the loader valves with one that has power beyond and feed it back to the right place
 
   / Rear hitch hydraulics with front loader help #15  
Thats strange as you would think it would have been working when who ever did it put it together, so with your current set up you are dead heading the pump as there is nowhere for the oil to go? until a leaver is operated, you would know as there will be load on the tractor, any valve with HPCO (high pressure carry over) would do, £100 from flowfit if you need it, same as the replacement I tried for my loader. On the picture above is the front hose going into P in the loader spool, with T on the loader spool going to the rear of the triangular block , that would explain why your arms are working as you mentioned only when the loader is operated as only then is oil flowing through the system, if your loader spool had HPCO that would return to the rear of the tri. block and the return line from the loader spool would feed into the centre port currently blocked dumping oil into the back end.
 
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   / Rear hitch hydraulics with front loader help #16  
So I feel like my options are:

Live without the 3ph
(I could at least feed the T port to the right middle hole from the loader)

Somehow source one of those under seat valves

Or, replace the loader valves with one that has power beyond and feed it back to the right place
You do not have to live without the three point.

There is a selector valve,, one inlet, two outlets.
Install that valve, select "A" if you want the loader powered, select "B" for the three point.

Not perfect, but, cheap, and easy to install.
 
   / Rear hitch hydraulics with front loader help #17  
You keep saying your loader valve dont have power beyond but you have 3 hoses going to your loader valve stack not counting the 4 function hoses.

its confusing because looking at your pictures we cannot see where both ends of a single hose goes and you havent labeled anything.

Take your pictures that you have....and label things and maybe we can help better.

Show the valve and label hoses like 1, 2, 3, etc. Then show the pic of the triangle and under the seat and label then as well so we know for sure what hoses are going where
 
   / Rear hitch hydraulics with front loader help
  • Thread Starter
#18  
Hey all - thanks so much for all the help you've all been providing so far, and sorry if my explanations haven't been clear enough. I think @chrismac that's what I need to do. I'm guessing the pump or somewhere in that unit under the seat there must be a relief valve - but you're right in your analysis that the pump is currently dead headed, which I've come to realise with this thread and the investigations :)

@LD1 I've done some annotations, hopefully this helps clear up the 7th pipe from the loader valve, but let me try to explain alongside:

Under seat - with annotations - that one labelled 1 is fed by that 7th pipe from the loader valve, which is only actuated when the third lever is raised

under seat - annotated.jpg


Then the loader valve - just showing the P port on the outside. There's no markings on the case by that port above, I'm assuming this is a relief valve? It has 1700 marked on it:

FEL block side - annotated.jpg


And the three levers:

loader levers - annotated.jpg


And finally the rear of the FEL valve:

FEL block front - annotated.jpg


And yes, when numbering things I didn't put a number 2 in there by accident!


Cheers

Martin
 
   / Rear hitch hydraulics with front loader help #19  
Well done you have sussed it, I had a guess that would be the way is was piped in, T returning back to the rear of the triangular block, all you need to do now is have a think about your next step, whats the fittings underneath the spool valve for? the ones you can see in the last photo.

Chris
 
   / Rear hitch hydraulics with front loader help
  • Thread Starter
#20  
Well done you have sussed it, I had a guess that would be the way is was piped in, T returning back to the rear of the triangular block, all you need to do now is have a think about your next step, whats the fittings underneath the spool valve for? the ones you can see in the last photo.

Chris
Do you mean the three on the bottom edge? I think that's where the arms go up and down with the spring inside that actuate the hydraulic fluid to the A and B ports for each set. I am thinking I need to take off the valve so I can actually see it properly and clean it up really well, to make sure I'm not missing a hidden carry over/power beyond port. It's all a bit tight down there - just need to nip back to the guy I bought it from as he forgot to give me the legs to attach to the loader to be able to remove it from the machine. Should give me much better access to look at it once the metalwork is out the way.

Glad I found out about flowfit from yours and a few others posts on here too - prices seem very reasonable. Did you ever sort out the issue with your valve where it would drop rather than raise if you were just feathering it?
 
 
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