Did I break something? Need help from the hydraulics gurus!

[UncleBuck1]

Measure the rods to see of their still equal in length one may be bent or the loader frame cockeyed.

May have bent the rod or wrecked an internal seal. Something has to give, and it's not going to be the fluid!

The tractor is at my farm about 50 miles away, so I won't be able to assess the damage until this weekend. The more I think about it I very easily could have bent something; it was the perfect combination of the bucket sliding up on a stump while the front wheels dropped into a depression. There was a lot of force at work in the split-second it took for this to happen.

i was thinking more something sticking open, like a relief or check valve, as sometimes he goes to do a function and gets a drop instead. not sure what type of spool he has, if it uses pilots, etc..

That's what has me scratching my head- and it's also the one thing that gives me hope; the loader will lift- sometimes- but other times it just drops! I don't have much experience (as in none) with hydraulics, but it seems that if it was a structural problem like a bent rod the problem would present itself consistently. I may try swapping the bucket and boom hoses around and see what happens.

Hopefully I got lucky and just blew out a seal or the pressure spike is causing the relief valve to stick.

 

[J_J]

It would be unusual for a relief valve to stick.

There is a spring that puts pressure on the plunger/poppet.

If the relief did stick closed, you would have no protection for the pump. You could blow a hose, fitting, etc

Usually the problem with relief valves is that some debris gets under the seat and you can't build max pressure.

 

[Avondale]

You may consider just using one cylinder at a time to lift an unloaded bucket, as in a complete disconnect one, try to lift, if ok, try the other? It may indicate if one or the other hyd rams is malfunctioning. If no change in either case, problem should be at the control valve and/or system relief.

 

[Soundguy]

It would be unusual for a relief valve to stick.

There is a spring that puts pressure on the plunger/poppet.

If the relief did stick closed, you would have no protection for the pump. You could blow a hose, fitting, etc

Usually the problem with relief valves is that some debris gets under the seat and you can't build max pressure.

it's more likely some sort of valving problem than a cyl problem, since he sees fine usage, then it will just drop... that is a control issue to me..

 

[Soundguy]

It would be unusual for a relief valve to stick.

There is a spring that puts pressure on the plunger/poppet.

If the relief did stick closed, you would have no protection for the pump. You could blow a hose, fitting, etc

Usually the problem with relief valves is that some debris gets under the seat and you can't build max pressure.

it's more likely some sort of valving problem than a cyl problem, since he sees fine usage, then it will just drop... that is a control issue to me..

 

[UncleBuck1]

it's more likely some sort of valving problem than a cyl problem, since he sees fine usage, then it will just drop... that is a control issue to me..

Let me clarify: as long as I keep my hands off the joystick the FEL holds steady; the problem occurs when I attempt to raise the loader- sometimes it rises, sometimes it falls.

 

[Soundguy]

ok.. if it holds steady, then it sounds like the check valve is working, but when you move the spool to pressurize the circuit, perhaps a pilot somewhere is sticking or failing and allows the circuit to depressurize. might be a spool with multiple oring and one is bypassing

 

[UncleBuck1]

ok.. if it holds steady, then it sounds like the check valve is working, but when you move the spool to pressurize the circuit, perhaps a pilot somewhere is sticking or failing and allows the circuit to depressurize. might be a spool with multiple oring and one is bypassing

You described my problem to a "T"- sometimes when I pull the joystick back the lift circuit pressurizes, other times it depressurizes. That's why I have a hunch that something is sticking as a result of the pressure spike that happened when the front wheels dropped and left the weight of the front end on the bucket.

I'm going to show my ignorance and admit that I have only a vague notion of what a pilot is; I think of it as the hydraulic equivilent to a solenoid - is that correct? And I have absolutely no idea of how they function; could a sudden pressure spike cause a pilot to stick? Are pilots repairable, or is it a replace the whole valve sort of problem?

 

[Soundguy]

Think of a pilot as a control system, a small circuit that controls a mother, usually larger circuit, so yes, in a way, a solenoid could fit the analagy.

As for repair??

I know on my dual remote pack on my nh 7610s, one remote worked fine, other was dead, however if you worked the first spool and held it in a function, and operated 2nd spool, 2nd spool worked as long as first spool was held.

Seals, detents, balls, orings, reliefs checked and replaced, didn't fix. Was declared a failure in that spools pilot ckt somewhere, repair via replacement in my case.. Not sure on your system. Its almost like sometimes when you pull the lever the system is operating in drop mode, or check is being released, but ckt not pressurized. Depends on how their spool is plumbed.

Ps is this an electric over hyd valve, or straight mechanical valve? Ie fly by wire or not?

 

[J_J]

You might check the load check valve.