Pressure releif valve - front loader - Iseki 1240

[Marcle]

Now got all the bits to do a pressure test on the hydraulic pump and found some time to do the test.

Just to recap, I carried out a pressure test on the FEL by splitting the 'up' line and inserting a gauge as shown in the photo below;



The above test showed a max pressure of around 1500psi (manual claims it should be 1800psi).

It would appear from the limited amount of stripping down done so far, I need to access the PRV inside the main gearbox, but simple things first, I've got extra fittings together to fit a needle valve and gauge on the output side of the hydraulic pump as shown below. Luckily there is a pipe connection between the exhaust pipe and steering box which is used for splitting the tractor to access the clutch. For anyone else going down this route, the pipe threads at this connection are not BSP, but Metric M16x1.5mm.



Well I'm sort of pleased as several people have tried to indicate my pump was tired, however winding the needle valve in slowly, I was easily able to take the pressure up to 3,000psi where the tractor started to change tone. I didn't go any further as that could have blown the pump seals, snapped the drive shaft and so on. But at least I know the pump is sound.

My next move subject to time, weather etc. is to lift the top of the gearbox off. It would have been nice to have had some detailed info for this, but...

 

[J_J]

Even though the pump is capable of the higher pressure, the manufacturer may have limited the pressure for different reasons.

If the flow goes through the FEL valve first, then the FEL valve relief will have master control of the pressure. You would normally set all pressure relief the same.

 

[Marcle]

If the flow goes through the FEL valve first, then the FEL valve relief will have master control of the pressure. You would normally set all pressure relief the same.

The FEL is not plumbed in series, otherwise you'd need a link hose when removing the FEL as its on quick disconnect hydraulic fittings.

Before lifting the top off the gearbox, I'm going to do another pressure test before the FEL valve chest as one guy rightly suggested the valve chest may have issues.

 

[J_J]

Unless you have a closed center hyd system all valves are plumbed in series.

If you remove the loader, the valve usually stays in place. Even if you did remove the control valve, and reconnected the hose from pump to the 3pt, the 3pt has it's own relief valve, so then the 3pt is the only relief valve on the hyd system.

Just because you are using QD's, does not mean that you can not reconnect the hoses together.

You simply want a series connection from pump to tank with all valves in between, connected in series.

 

[J_J]

Marcle ,

I notice two different tractor numbers related to this post. 1240 or 2140.

Which model do you have?

REF: first post.

 

[Marcle]

The model number is a typo, the correct number (in full) is TX2140F.

With regards to the hydraulics, we can talk till the cows come home, and the only way to know exactly what's what, is to lift the lid off the gearbox and see.

BTW the valve chest stays with the FEL when its removed, leaving three QD fittings on hoses going to the gearbox.

 

[J_J]

If you have three hoses left after removing the loader, you would connect the pump OUT hose to the PB hose, which would go to the 3pt, and the TANK hose/OUT hose could be left as is with the QD.. You simply want a connection from pump to the 3pt if no loader is used.

Most pressure relief valves are located in plain sight.

Show us some pictures of the rear end up under the front of the seat.

 

[Marcle]

Show us some pictures of the rear end up under the front of the seat.

I've already posted photos in this thread showing what's under the seat. I've also posted photos of the hose connections on the side of the gearbox. There is *no* external point to alter the PRV. As previously posted, the only external one on the tractor is on top of the internal hydraulic ram for the rear arms.

There's no real need to theorise what may or may no be going on until I get the top off the gearbox to trace through the hydraulic circuit.

 

[chrismac]

Well... I've stripped hydraulic manifold off the side of the gearbox as shown in the photo below
View attachment 275198

View attachment 275199
Well the block is just a manifold, nothing more. looking down the holes on the side of the gearbox, there are no screws, all you can see is a port drilled off to the side and the bottom of a drilled hole. I even removed the bolt holding the pressure line from the pump to see if there was any screw within the threaded hole. nothing...

In another vain attempt to find a hidden adjustment screw or what ever, I took the pressed steel seat bracket off the top of the gearbox, but nothing.
View attachment 275200

Well I'm stuck again....

Marcle,

or anybody, can you tell me which hose ports are the flow and return on the block attached to the tractor 3 pt linkage hydraulics, I am in a similar position where I am coming close to getting this set up on my tractor, I guess I could block off all the ports should I want to run the tractor before I get the hydraulics set up should that be the case?

Thanks