BX-25 backhoe relief valve adj.

[doghouse]

Hello I was wandering if anyone ever adjusted the relief valve on there backhoe. I checked the pressure going to the hoe and it's all right ] My problem is when I pull the dipper towards me when digging it just stops at times when hardly digging The same goes for the bucket when you curl it towards you. Need some advice

 

[J_J]

With the hyd gage in the IN port in a tee, what is the pressure when using the dipper and the bucket.

Can you make relief pressure using the bucket or the curl.

Can you make relief pressure using the boom.

How did you check the pressure?

How much wear and tear has the BH seen?

You have GPM that determines speed of operation, and the pressure that determines the force.

So, if the cyl seals are leaking, there goes your force, and if you are not running the tractor engine at max rpm's, you are not producing the rated GPM's.

 

[doghouse]

I checked the pressure at the back of tractor were the line comes off the tractor and hooks to hoe . have 1850 psi. I don't know how to check relief pressure at the dipper and bucket.

 

[doghouse]

No leaks anywhere,. Tractor has not seen a lot of wear and tear. I run the RPM'S at 2900 when digging

 

[J_J]

If your cyl have internal leaks, you will not see them, as the fluid just slips by the seals, called bypassing.

Tell us what the pressure are.

 

[J_J]

I checked the pressure at the back of tractor were the line comes off the tractor and hooks to hoe . have 1850 psi. I don't know how to check relief pressure at the dipper and bucket.

Is that pressure your tractor rated relief pressure? Look in the manual.

If your hyd gage is in a tee in the IN port of the BH valve, using any function on the BH will read the pressure for that component. If your cyl are leaking, you should not achieve the 1850 psi.

If your tractor pressure is 1850, the BH relief valve should be set at 1850 psi. Fully retract any cyl on the BH and see what the relief pressure is. Do this for each BH cyl.

 

[Tractor Seabee]

Looking through my BX 25 WSM there is no relief valve that sets the BH pressure less than the main relief on the tractor hydraulic circuit. There is an an overload relief valve that opens at pressures well above the 1850 you have in the power circuit. 1850 is the factory setting for the hydraulic circuit. The overload valve is to relieve any pressures developed in the BH system by operations developing an outside load. The BH, FEL, and 3 Point all operate at the 1850 PSI w/o any more pressure controls.

JJs pressure checking is right on except that the BH does not have a relief that controls the operating pressure.

Ron

Ron

 

[doghouse]

Thanks everyone

 

[J_J]

Looking through my BX 25 WSM there is no relief valve that sets the BH pressure less than the main relief on the tractor hydraulic circuit. There is an an overload relief valve that opens at pressures well above the 1850 you have in the power circuit. 1850 is the factory setting for the hydraulic circuit. The overload valve is to relieve any pressures developed in the BH system by operations developing an outside load. The BH, FEL, and 3 Point all operate at the 1850 PSI w/o any more pressure controls.

JJs pressure checking is right on except that the BH does not have a relief that controls the operating pressure.

Ron

Ron

Seems to me that most all BH would have their valve relief.

Can you explain how the over load relief works, and are you talking about work ports relief.

So if the loader relief is setting the relief for the BH then the BH could never exceed the tractor pressure of 1850 psi.

However the cyl could see pressure above that by mechanical force acting on the BH cyl. Each cyl work port would need a relief valve.

Can you show pictures of the relief you are talking about?

doghouse ,

Can you post the psi reading for each of the BH cyl using the retract mode until the relief goes off, if it ever does.

A good cyl will develop full relief pressure in fully retracted or extended mode.

Kubota BX25-LA240-BT601 | Backhoe Loaders Equipment Specs


Backhoe:
Backhoe type: Kubota BT601
Weight: 617 lbs [279 kg]
Digging depth: 73 inches [185 cm]
Reach from pivot: 103 inches [261 cm]
Loading height: 60 inches [152 cm]
Bucket force: 1,936 lbs [878 kg]
Dipperstick force: 1,171 lbs [531 kg]

 

[J_J]

I just talked to the tech's at Messicks, and not to my surprise there are multiple relief valves on the BH valve, with each one having different relief settings.

The purpose of the work port reliefs is so the mechanical forces do not damage the hyd components.

These work ports reliefs are independent of the tractor hyd pressure.

The force that each cyl is developing is related to the tractor pressure.

I will have the schematic in an hour so I can tell you more.