Kubota Relief valve shim?

[bandaidmd]

I did a search and got 1700+ possibilities so i will just re'ask this.

I tested the pressure on my B2620 kubota loader(quick connected to the curl curcuit) and it shows 10% low (1900 on a 2000# system)

Will I notice the difference by going in and shiming the popoff up to spec ?

my rear remotes are in series between the loader and the 3ph and i lose 50#at the rear remotes so i guess by the time the 3ph gets its juice it prob down another 50

Anybody got a picture by picture walkthru of the relief valve adjustment/shim process.

 

[J_J]

Basically, you add shims to increase pressure.

Install a hyd gage, start engine and check the pressure, and if low, shut off the engine and remove the relief assembly and add shims as necessary to meet your demands. About 50 to 100 psi below pumps max pressure.

Hyd pressure is caused by the resistance to the fluid. Hyd cyl and motors develop the pressure due to load.

You lose pressure by the seals leaking, or the pumps inability to generate the pressure.

There may be a difference between hot and cold fluids.

 

[bandaidmd]

Thanks for the quick reply JJ but ... your saying my tractors stated hyd pressure of 2000 is normal to only be 1900 at the very first implement in the flow?
I doubt theres much wear @15hours

I already understand the part of shimming the spring because theres no threaded adjuster, im curious as to whether i will even tell the difference with a 100# extra pressure.

 

[J_J]

If you install a hyd gage in a tee at the IN port of the loader valve, you can see the pressure developed by any hyd cyl, up to the relief setting.

If the fittings and hoses are the same size you should not have a significant loss.

It would be easy enough to check the pressure by adding a gage up front and a gage in the rear.

Keep in mind that the 3pt may have a different relief setting.

A tractor with out attachments, only has the 3pt relief for the total tractor relief, and when you add a loader, you should set the loader relief to the tractor relief setting, or set them all the same.

 

[PhysAssist]

Thanks for the quick reply JJ but ... your saying my tractors stated hyd pressure of 2000 is normal to only be 1900 at the very first implement in the flow?
I doubt theres much wear @15hours

I already understand the part of shimming the spring because theres no threaded adjuster, im curious as to whether i will even tell the difference with a 100# extra pressure.

Hi BandAidMD,

You are correct and your lowered pressure is more than likely Kubota's attempt to reduce the chances of injury or damage to your system by using it at its specified rating, as many have found evidence ofbefore you.

The question I keep coming up with based on JJ's answers to this and prior questions in this line of reasoning is how do you measure the pump pressure as in "about 50-100 psi below pump pressure".

The only measurements people seem to be making are of relief valve settings, not the provided pump pressure.

Thanks JJ,
Thomas

 

[J_J]

Using a 2 in cyl bore, and a 1 in shaft, and 2500 psi.

If you increase the relief pressure to 2600 psi, you gain about 314 lbs of pushing force.

However if the 3pt is a 3 in bore cyl, increasing the pressure to 2600 psi, you gain about 707 lbs.

The manufacturer don't seem to want to publish the rated pressure of the pumps, and the engineers want to keep the relief pressure below the max pressure.

Some people just want to tweak it up, because the can.

 

[ultrarunner]

Sounds like you are 5% low...

Mine was 8% and I did notice overall improvement when I got within 20 lbs of spec...

The loader could now lift a heaped load where before it almost could.

 

[bandaidmd]

Sounds like you are 5% low...
oops .....you rite

so your 8% was a noticeable difference ,thanks thats what i wanted to know. Did you shim it yourself?

 

[bandaidmd]

Sounds like you are 5% low...
oops .....you rite

so your 8% was a noticeable difference ,thanks thats what i wanted to know. Did you shim it yourself?

 

[ultrarunner]

Yes... I had some very small stainless flat washers left over from a Zeiss medical microscope and used one and double checked pressure with a guage.

Performance increase was noticeable and it's nice to be able to lift a full loader of dirt.

As always, the greater the loader load, more caution required.