Diverter Valve troubleshooting

[xanadu1797]

Hi everyone,
I'm trying to get some insight into what is going wrong with my Kubota B26. I had my mechanic install diverter valves in the front and rear of the tractor to accommodate a grapple and a hydraulic thumb. Since then a couple things keep happening

In the rear the backhoe spool valves (which had been rebuilt a few years ago) started leaking and one of the outriggers operates very slowly. It's been already repaired once, and then began leaking again.

In the front- when using the diverter valve to operate the grapple the boom cylinders sort of pinch down on the left side when closing the grapple fully. Now the boom cylinder (also recently rebuilt) is leaking. I chose the boom cylinders for the diverter valve because of the regen function on the curl circuit.

Are these diverter valves blowing my seals? Could this be pointing to the relief valve not operating properly?

 

[oldnslo]

What type of diverter valves do you have and where are they plumbed in the circuit. If installed correctly a diverter should not have any effect on seals or how back hoe valve functions.

Some pictures of the valves installed might help.

 

[xanadu1797]

They're surplus center solenoid diverters. 6 gpm
Not sure if pictures will be very useful but the forward valve is mounted beneath the right floorboard and is connected to the boom circuit. When the grapple closes fully it squishes down the left side of the boom. Doesn't look right but I don't think it's hooked up incorrectly.
The rear valve is plumbed in by the three point hitch.
I checked the breather tube- that's clear.

 

[zzvyb6]

From my experience, you have 2 improper connections to trace. Similar attachment issues occur with loader, mower, and plow hose misplacements. Slow, jerky, erratic bucket and unwanted arm movements. Retrace the 'wiring' diagram.

 

[oldnslo]

They're surplus center solenoid diverters. 6 gpm
Not sure if pictures will be very useful but the forward valve is mounted beneath the right floorboard and is connected to the boom circuit. When the grapple closes fully it squishes down the left side of the boom.

Is squishing down retracting the left lift cylinder but not the right?

Doesn't look right but I don't think it's hooked up incorrectly.
The rear valve is plumbed in by the three point hitch.

You need to verify what line this diverter is connected to. I would be concerned that it might be a tank line which would cause the back hoe to leak around the spools and if pressure builds to high crack the castings.

I checked the breather tube- that's clear.

 

[kennyd]

They're surplus center solenoid diverters. 6 gpm

Can you link to the EXACT valves used? Not just the homepage???

6GPM sounds awfully small for your B26.

 

[TMGT]

Can you link to the EXACT valves used? Not just the homepage???

6GPM sounds awfully small for your B26.

Most likely this valve SAE 8 6 GPM Double Selector Valve 12 Volt DC P15544-2 | Selector Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com

The B26 is only 6.9gpm on the loader circuit so a 6gpm is fine on a diverter valve, I run the same valve for an extra rear remote on my L3240.

Would be nice to see how its hooked up, what he describes doesn't make sense to be caused by the diverter, at least the front one. Rear I'm not sure what circuit he has it hooked into.

 

[xanadu1797]

This is the exact valve used on both front and rear

SAE 8 6 GPM Double Selector Valve 12 Volt DC P15544-2 | Selector Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com

SAE 8 6 GPM Double Selector Valve 12 Volt DC P15544-2, Selector Valves, SAE 8 6 GPM DOUBLE SELECTOR VALVE 12 VDC P15544-2, SOLENOID OPERATED DOUBLESurplus Center,P15544-2 ,

www.surpluscenter.com

 

[xanadu1797]

Is squishing down retracting the left lift cylinder but not the right?

You need to verify what line this diverter is connected to. I would be concerned that it might be a tank line which would cause the back hoe to leak around the spools and if pressure builds to high crack the castings.

Correct- the loader squishes to the left when I close the grapple fully.

I’ll try and figure out what line the rear is plumbed to on the spool valve.

 

[xanadu1797]

Could someone explain why you shouldn’t plumb to the tank line and what would be the alternative configuration?

 

[TMGT]

Could someone explain why you shouldn’t plumb to the tank line and what would be the alternative configuration?

If both valves installed were diverter (selector) valves, then they should have been connected to the work ports of an existing spool valve. If the diverter valves are actually actuating the cylinders correctly then there's no way it was connected to a tank port.

Now if they also added a spool valve to the system or the cylinders aren't working correctly then I could see a plumbing problem.

The loader cylinders are Tee'd together, so unless they somehow managed to get the diverter after the Tee, I dont see how it would effect one boom cylinder. (The Tee is located on the loader cross bar)

 

[oldnslo]

Could someone explain why you shouldn’t plumb to the tank line and what would be the alternative configuration?

If the diverter is installed in a tank line in such a manner that it creates back pressure on that line it could damage valves and components up stream. I.e. relief valves would operate at higher pressures, potentially blow seals around directional valve spools, worse case crack a valve housing.

How many hoses are connected to these diverter valves?

 

[TMGT]

If the diverter is installed in a tank line in such a manner that it creates back pressure on that line it could damage valves and components up stream. I.e. relief valves would operate at higher pressures, potentially blow seals around directional valve spools, worse case crack a valve housing.

How many hoses are connected to these diverter valves?

The diverter only has 6 ports, 2 connect to the work ports of a directional control valve and the other 4 ports connect to whichever cylinders you want to control.

If the 2 circuits the diverter is controlling are working, then it is plumbed correctly.

Loader mounted one is pretty straightforward, however I'm wondering what control valve is being used for the rear diverter.

Sent from my SM-S921U using TractorByNet mobile app

 

[xanadu1797]

Both lines coming off the back of the diverter go to the connection on the spool with the red zip tie (second from left.


On the front of the valve there’s a red line zip tie on the left and a green on the right.

 

[xanadu1797]

Could it be a problem with back pressure from the force of the bucket pushing against the thumb?

 

[oldnslo]

Could it be a problem with back pressure from the force of the bucket pushing against the thumb?

Which function do you have to operate for the thumb to function? That should be the only function effected by any bucket force on the thumb.

 

[LouNY]

Are both solenoids being activated at the same time?
They need to be, they both have to operate to switch the function one circuit to the other.

Also they should be wired in parallel not in series.

 

[LouNY]

I much prefer this type, just one coil to fail. One pair of wires to connect a hot and a ground.
Less to go wrong and easier to install and they can be stacked for multiple circuits.

 

[TMGT]

Could it be a problem with back pressure from the force of the bucket pushing against the thumb?

Definitely a possibility, a work port relief for the thumb is a good idea. What function is the thumb diverter on?

Sent from my SM-S921U using TractorByNet mobile app

 

[charlessenf]

Could someone explain why you shouldn’t plumb to the tank line and what would be the alternative configuration?

And, while at it, explain how to determine you are about to mess with the 'Tank Line."