# "Oz Quip" front end loader control lever servicing



## JillMitsi2244 (Aug 4, 2021)

I am having trouble with hydraulics on Mitsubishi D2350 (full story here Mitsubishi D2350, 25hp 4WD 4cyl with FEL import...), but I finally got movement of rear hydraulics so now want to troubleshoot the FEL control lever. Very briefly, hydraulics stopped a few months ago, I pulled off the hyd pump, filter and oil, found no issues, replaced and all was working perfectly after I put it all back together, for a couple of months. Hydraulics stopped again, I pulled the cover off the gearbox? pulled off the control valve and found a very stuck unloader valve. Cleaned that all, put it all back together. Now the rear hydraulics are working (very slowly but at least working), but absolutely nothing from the FEL. I can hear air squirming slightly, when the engine is off and toggling the lever between crowd, dump, up, down. So I'm guessing the lever control unit is not getting any oil or it's mixed with air, so not working.

Oz Quip are apparently now out of business and no reference to them can be found, but I would think it's a fairly generic control lever and if I could get some guidance as to which bits to pull off and check it would be greatly appreciated. 
There are 4 hoses (up, down, crowd, dump) and then a hose either side (guessing feed in, and return). The two big silver caps on the bottom, can I pull them off and service/clean a valve in there?
The feed comes from the top of the control valve, from what looks to be a straight adapter plate (that replaced the original "Relief Valve" on the Mitsubishi D2350). I assume that there is some sort of relief valve in the FEL control lever unit to take over that function.
This is the control lever top (cover removed), then from the bottom.
















Can I pull those silver caps off and check/clean? Is there a valve in them that could be stuck?


----------



## HarveyW (Sep 15, 2014)

Does your tractor have a front engine mounted hydraulic pump? OR does it operate off the tractor's internal hydraulics? Often times, loaders are operated with front engine-mounted hydraulic pumps.


----------



## FredM (Nov 18, 2015)

If you need to remove those silver covers, you will find the centering springs for the raise/lower and crowd/dump spool valves, at each end of the spool valve housing there is an O ring, and if you pull the spools, you will need to replace the O rings, otherwise you will get oil leaks.

The pressure relief valve on the controller block will have a threaded stud and locknut and the exposed end will have either a screw driver slot or internal hex for adjustment, if you pull this relief valve , mark the position of said stud and nut, it is possible that the spring that holds the valve could be broken, but I doubt it, most times the pressure input hose is on the opposite end of the controller housing to the pressure relief valve.


----------



## JillMitsi2244 (Aug 4, 2021)

HarveyW said:


> Does your tractor have a front engine mounted hydraulic pump? OR does it operate off the tractor's internal hydraulics? Often times, loaders are operated with front engine-mounted hydraulic pumps.


Thanks Harvey, it has a hydraulic pump on the side of the engine, like a "normal" tractor, I would think. The hoses to the FEL come from an adapter plate on the hydraulics/gearbox cover (under the seat). The adapter plate is where the "relief valve" is normally positioned, so it looks like the FEL fitters replaced the Relief Valve with the adapter plate, adding a feed and return line from the tractors hydraulics/Control Valve. I was going to try and service the tractor's Relief Valve, but that's when I discovered I didn't have one - it had been replaced with an adapter plate. I have since learned that the Akon FEL control unit has it's own Relief Valve, which is what I want to pull off. I am just concerned because they apparently are set to a certain pressure, so I'm hoping if I am really careful to take note of the position of the top nut or any locknuts, to put it back the way I found it.


----------



## JillMitsi2244 (Aug 4, 2021)

FredM said:


> If you need to remove those silver covers, you will find the centering springs for the raise/lower and crowd/dump spool valves, at each end of the spool valve housing there is an O ring, and if you pull the spools, you will need to replace the O rings, otherwise you will get oil leaks.
> 
> The pressure relief valve on the controller block will have a threaded stud and locknut and the exposed end will have either a screw driver slot or internal hex for adjustment, if you pull this relief valve , mark the position of said stud and nut, it is possible that the spring that holds the valve could be broken, but I doubt it, most times the pressure input hose is on the opposite end of the controller housing to the pressure relief valve.


Thanks Fred, is it possible that any sludge or gunk could block or stick the Relief Valve? The unloader valve in the Control Valve (inside the gearbox/hydraulics cover) was definitely stuck, but I cleaned all of that thoroughly. After testing yesterday the rear hydraulics were working (slow but working), but absolutely nothing from FEL hydraulics.
The only Relief Valve appears to be the one on the Akon controller. Can I just pull it apart, taking careful note of any locknuts, stud positions to ensure I don't change the current pressure set?


----------



## FredM (Nov 18, 2015)

You can dismantle the pressure relief valve no worries, I have already mentioned what to take note of, it is possible for the valve to be not sitting on its seat, a broken spring would or could be a possibilty, some solids under the seat and not allowing it to hold pressure in the system, these are possibilities but mostly not probable.
I have tried to transfer a photo of the flow control lever you previously attached to the forum, can you tell me exactly what this does and how many positions the lever has please?.


----------



## JillMitsi2244 (Aug 4, 2021)

The flow control under the seat, for hydraulic pressure? It is just a short lever with no set positions. Full flow when turned to the left, and low (which supposedly locks the hydraulics) when turned fully to the right. 180° movement from full to lock. I try to leave it in mid position, but it moves very freely (always has), so I sometimes knock it with my foot (to the right, lock) when getting into the seat. I will pull the reluef valve on control unit apart tomorrow hopefully. 
Would there be any use in removing the flow control lever and clean?
Thanks for your help.
Would there be any benefit of priming the control block with oil at any point when I reassemble?


----------



## FredM (Nov 18, 2015)

Your flow control valve is what I think to be the 3 point lowering speed rate, full open the implement will drop fast and towards lock, the implement will drop slower, that what I thought it was.

No, there is no point in removing the flow control as you call it.

When you re-assemble the control valve, make sure you lubricate the spools and housing before replacing, no need to prime this,-- it is the pump that has to be primed after being dismantled or the suction line opened up.


----------



## JillMitsi2244 (Aug 4, 2021)

The Control valve under the case cover, that has the Unloader valve in it? I'd hate to have to pull that cover off again, but I'm thinking maybe I might need to. When I pulled the Control valve off, all I did was remove the large (about 20mm) flat ended solid nut from the end to release the unloader valve (I didn't touch the other large flat nut with a hole in its centre). The unloader valve was stuck in sludge/gunk so much I had to pry it out with a screw driver (through the shafts side air/bleed/inspection hole). But I cleaned the shaft thoroughly, then rinsed the entire control valve with petrol, without dismantling any more of the Control Valve. Before replacing the cover I drizzled hydraulic oil into the holes of the Control valve, then replaced the cover. 
Maybe I should have pulled it completely apart to clean all parts?


----------



## FredM (Nov 18, 2015)

The control valve we are talking about is the loader control with the 4 way joy stick!!.
I just asked a question about the flow control valve to satisfy my curiosity.


----------



## JillMitsi2244 (Aug 4, 2021)

I'm still waiting for O rings to arrive, but decided to pull the loader controller relief valve out to check it wasn't blocked or broken spring.
Its an Akon controller, havent been able to identify exact model. This is the relief valve. There are no obvious problems, seems very simple. Not even adjustable pressure, seems to be controlled by the spring alone. The shaft bit into the bottom of the housing didn't "fall" out, had to give it a little help through the hole in the side, but there was minimal anything in the bottom, I figure it was purely oil friction holding it in place. No gunk like I found in the tractors Control valve Unloader valve. So I'll put this back and wait for the O rings to do the Control valve job again. (will pull the gearbox cover off, Control Valve out, give new O rings to anything touched and reassemble again, take it from there.


----------



## FredM (Nov 18, 2015)

To raise pressure, the through stud that has the 2 nuts on it is more than likely screwed in to raise pressure, otherwise there would be no reason to have an adjustable stud there, there is most likely a seat for the spring attached to the guide and this is all part of the stud.


----------



## JillMitsi2244 (Aug 4, 2021)

FredM said:


> To raise pressure, the through stud that has the 2 nuts on it is more than likely screwed in to raise pressure, otherwise there would be no reason to have an adjustable stud there, there is most likely a seat for the spring attached to the guide and this is all part of the stud.


Aha! k. Yes the threaded stud in the top of the housing marked "Z" has a hex allen key for adjusting. I was careful not to move it, have taken the measurements (exactly 10mm of thread showing) and will pull that out for further inspection. Thanks Fred!


----------

