Shimming Pressure Relief Valve

[Skinnyman]

Have any of you folks shimmed or adjusted the pressure relief valve to achieve max system pressure for the loader? Per the manual, max system pressure is 2611 psi. Warmed up and at 2000 rpm I am only getting 2400 psi. I think it would be worth the effort to get to 2600 psi. Any help on the shimmning or adjusting process would be so welcomed, like location of PRV and where to obtain shims, etc...I have a 2009 CT235.

 

[milkman636]

Just for clarification, are you only getting up to 2400 psi or is the valve audibly relieving pressure at 2400 psi?

 

[dfkrug]

Have any of you folks shimmed or adjusted the pressure relief valve to
achieve max system pressure for the loader? Per the manual, max system pressure is 2611 psi.

My CT230 arrived new with the RV set at 3000psi. Setting the system/FEL RV properly is very easy, and
no shims are used. It is under the right side floorboard. Remove the cap and turn the inner screw clockwise
for more pressure. The service manual shows you where it is.

Note that these tractors from Kioti or Bobcat (DaeDong M27) are the same, but the Kioti is specced at 2560psi.

 

[Skinnyman]

Milkman, with the gage on the quick connect port for lowering the loader and opening and holding the port open, I am only registering 2400 psi. I held the port open until the gage was at max reading. I am not sure I have heard the relief valve open.

 

[SSdoxie]

Hook the gauge to the lift Up connector and test it pulling back on the lever. If moving the lever too far in down the spool might get to close to going into float and start bleeding some oil off there. If you have rear remote, plug your gauge in there and activate the remote lever. Rear remotes work off the loader valve relief.

 

[Skinnyman]

Good tip about the float position. I have already adjusted, but will go back verify using the lift port.
Thanks guys for the help.

 

[Skinnyman]

Re-checked psi using the port to lift loader, still showing 2600 psi. Good tip, feel better after re-checking.

 

[J_J]

Actually, your 2611 psi, was probably set at the factory for the 3pt before any attachments, and is the reference to set the other valves to the same setting.

So if you have a loader and remotes, you would set all the relief valves the same. That would also make the loader relief valve the master relief since it is first in the series path of the fluid.

It would be a good idea to install a hyd gage in the IN port of the loader valve where you can see it for monitoring and trouble shooting the hyd system.

 

[Skinnyman]

Thanks JJ. Have I errored upping the loader relief valve from 2400 to 2600? The manual quoted "system relief @ quick couplers 2611 psi".

 

[dfkrug]

The CT/CK has one regular RV (2500-2600psi) and one shock RV (about 3000psi) in the
3-pt valve. There is no separate RV for the FEL, just the one I mentioned above. Only
the first regular RV is adjustable.

Since you mentioned the RV spec for your CT235, I assumed you have the service manual,
which shows you where the RV is.

 

[Skinnyman]

Yes I do DF. Thank you guys for all the help and advice.

 

[J_J]

Thanks JJ. Have I errored upping the loader relief valve from 2400 to 2600? The manual quoted "system relief @ quick couplers 2611 psi".

Can you show a pic of your FEL valve and remote valve if you have one.

If the tractor came set at 2611 psi, the pump pressure is probably capable of higher pressure.

If you have a hyd block, show a pic of that also.

Just curious how many relief valves you have.

It is odd to see a FEL valve without a relief valve.

You should be correct to set all the reliefs to 2611 psi.

 

[Skinnyman]

The relief valve I adjusted was at the fel valve. I have a itergal joy stick. I will try to get a picture today. I do not have any remotes.
Thanks for interest.

 

[Skinnyman]

JJ, pics of fel valve where PRV was located.

View attachment 341008View attachment 341009

 

[J_J]

Just for grins, plug in the gage at the IN port of the loader valve, and raise the 3pt to max and cause the relief valve to activate and read the pressure.

The 3pt may activate at a lower pressure, and if so, just bump it up to 2611 psi as stated in your manual..

All the relief setting should be the same.

 

[dfkrug]

The relief valve I adjusted was at the fel valve.

SKINNY: that's the only adjustable RV in your hydraulic system, even if you added the
factory remote valves. If you had no FEL, DaeDong puts another hydraulic block with
RV where your FEL valve is currently located.

On the right side of your 2nd photo, you can seen one of the hydraulic pressure lines,
which use a banjo fitting. This makes it very difficult to plumb anything into the IN
or PB lines, like a pressure gauge.

I put my gauge at the cylinder end of a FEL work port hose (photo), or at one of the AUX
valve workport outlets, then operate that valve to relief.

I have owned, worked on, and modified 3 of these tractors.

 

[dfkrug]

If the tractor came set at 2611 psi, the pump pressure is probably capable
of higher pressure.

No. You can not assume that. My Bobcat came set to 3000psi, and I know of one other set higher
than spec. There were clearly some QA issues in Fargo. It is bad enough that Kioti specs it at
2560, and Bobcat uses 2611, tho the pumps are identical.

 

[Skinnyman]

Bye the way DF, did you re-adjust to 2611 psi per manual or leave it higher.

 

[J_J]

No matter what someone else set their relief valve at, use what your manual says.

There may be other reasons why they set the pressure to 2611 psi.

Some people try and tweak it higher for more power, but it is hard to know how far to go up on the pressure relief and still be safe.

As far as where to put the gage, if you plug into a work port as dfkrug says, you will only read the pressure for that valve work ports.

If you can find a place to add a tee after the pump but before the first valve, that would be the place to add a pressure gage for the total system. If your hyd system only has banjo fittings, it will be hard to mount a gage permanently. It can be done by cutting and using a compression tee fitting for the gage.

So if you install the gage after the pump, which ever valve lever you operate, you will read the pressure on that circuit, be it the 3pt, remote valve, or loader valve.

The pressure gage after the pump in series with the hyd flow, will let you monitor and trouble shoot the hyd system.

If you only plug the gage in a work ports, you will read the pressure the cyl is developing.

If you raise the loader empty, you might only read about 500 psi to 800 psi.

 

[J_J]

No. You can not assume that. My Bobcat came set to 3000psi, and I know of one other set higher
than spec. There were clearly some QA issues in Fargo. It is bad enough that Kioti specs it at
2560, and Bobcat uses 2611, tho the pumps are identical.

And yes, I can assume that as they would never set the relief to the pumps max pressure.

The pressure is probably set lower to protect the pump, and other components.

I would assume that they pay those engineers big bucks to come up with the correct and safe settings and limits on load, digging power, etc.

What if those cyl have a 2500 psi rating. Would you set the relief pressure to 3000 psi?