Return filter blocked???

[Despo1998]

G’day all
Juts thought I’d ask the question as I’m still having slow/no hydraulic pressure.

Could the return filter be the problem for very slow hardly moving hydraulics? It’s very hard to get to on my machine and I don’t think it has been changed recently if ever
Cheers

 

[Coaldust]

If the return filter is plugged, it will be plugged with thousands of dollars. Maybe, tens of thousands of dollars worth of hydraulic pump. It will be like panning for gold.

But yeah, preventative maintenance never hurt nobody. Good thing to check.

 

[aongheas.macask]

If the return filter is plugged, it will be plugged with thousands of dollars. Maybe, tens of thousands of dollars worth of hydraulic pump. It will be like panning for gold.

But yeah, preventative maintenance never hurt nobody. Good thing to check.

Don't know what machine this is but if return filter is blocked it will normally go into bypass, in itself this would not cause slow hydraulics unless as Coaldust suggests your hyd pump has destroyed itself , finding steel and brass in the filter would be a good indication, good luck

 

[Tom3697]

Yes, the return filter could indeed be the cause of very slow or hardly moving hydraulics. A clogged or malfunctioning return filter can restrict the flow of hydraulic fluid, leading to reduced pressure and sluggish operation.

 

[funwithfuel]

I would be more concerned with pilot oil as a cause for slow hydro. Good luck

 

[aongheas.macask]

Perhaps you could tell us what machine your are having trouble with.

 

[Despo1998]

It’s a new holland LE16
Over the last week I took the pump off and took it to a hydraulic shop and they said the pump is in perfect condition. I also got a new return filter and put it all back together and still nothing. Now when I check the pressure at the pump the gear pump is spot on making 500psi as per the manual but when I check the pressure at the main pump body (piston pump) the needle hardly moves when I move the controls. It sounds like a lot of cavitation coming from the 2 inlet hoses from the pump to the valve body but only when I move the controls. I’m still a little suss on the pump even though the technician went through and said it was perfect. Any help is appreciated

 

[funwithfuel]

When you had the pump off, did you clean out the tank? Did you inspect the sump strainer?

 

[Despo1998]

When you had the pump off, did you clean out the tank? Did you inspect the sump strainer?

Cleaned out the tank thoroughly and cleaned the strainer filter to. Just went out and tested the pressure again and it’s making 200psi but should be more like 2900-3000psi

 

[funwithfuel]

Don't confuse standby with work. A variable displacement pump produces standby pressure at idle with no requests made. At the same time, either through stand alone vane pump or pressure reducing valve on main feed, you have pilot pressure built up. The pilot oil feeds your joysticks with approximately 450-475 psi. The joysticks, based on your physical input, send a proportional oil pressure to move the spool to exercise a function. When the spool shifts off neutral, it allows some of the "main" oil to leak by in what's known as load sensing. The load sensing line carries that pressure to the pump which changes the displacement, commonly referred to as "stroking" the pump. Increased rpm, combined with increased volume give you work flow. As you reach the end of travel or a pressure which the pump can't support, the pump destrokes either by electronic pump regulators or simple flow compensators which effectively throttle the pump to avoid damage.
This is kinda the "cliff notes" version of how it works if, IF you have hydraulic pilot control. If you have cable and clevis, it'll be completely different. Good luck, hope this helps

 

[92U 3406]

If the return filter was plugged up you'd have a couple thousand PSI back pressure. You'd see the return lines jump just as bad as the supply every time you used a function.

Assuming there is no filter bypass of course.

 

[Despo1998]

Okay so where should I be looking next? I’m at my wits end with this thing

 

[funwithfuel]

Do you know what kind of controls you have? Are they pilot or cable? What does your control valve look like? Does it have nothing but hoses or are cables attached? Again, I don't know your machine, so I'm talking generalities.

 

[Despo1998]

Do you know what kind of controls you have? Are they pilot or cable? What does your control valve look like? Does it have nothing but hoses or are cables attached? Again, I don't know your machine, so I'm talking generalities.

They are all pilot controls but the dozer and boom swing are cable

 

[funwithfuel]

So I'll bet the 2 functions on cables work properly?

 

[Despo1998]

So I'll bet the 2 functions on cables work properly?

Nope, the blade hardy comes up/very very slow and if I put a foot on it and raise it it won’t come up and same with going down it won’t even try to lift the machine. Same with boom swing just no pressure

 

[funwithfuel]

That's a curveball I wasn't expecting. Since those 2 functions should run independently off the gear pump. This has to be tied into the safety solenoid. That is the single thing that controls all. Unfortunately I don't know where it is located, to tell you. The only thing I can suggest is to follow the pilot lines back from one of the joystick. 4 will go to spool caps, 1 will go to a pilot manifold and the last will go to a tank manifold. Once you find the pilot manifold, you can follow it back to a solenoid valve. Make sure there is voltage present at the solenoid when the armrest is lowered. If it's less than battery voltage, or looks bad from corrosion you may be able to manually stroke the stem. Sometimes in the center of the stem, there is an exposed center. Sometimes it'll even have a center drilled in it. Simply spray it with a little penetrating oil and gently push it in with a scratch-all or ice pick or whatever pokey thing you got handy. The other thing , to validate, you can remove the magnet from the stem, put the armrest down and see if that magnet will even hold the pokey thing you're using. If it won't hold or even try to grab it, the mag is probably going out. You could also measure the coil with the ohmmeter. Somewhere between 20 and 2k ohms. It depends on manufacturers. I hope this gives some direction, vague as it is. Good luck

 

[Despo1998]

Okay so from looking at the machine the only electronic solenoids I have are 2 that are connected to a block with the gear pump hose going into it. Am o correct to assume they are the solenoids you are talking about and what I should be looking at?

 

[funwithfuel]

Again, I can't say with 100% certainty. I don't know your machine and have no supporting literature. I'm speaking in generalities. Suggesting what I would look for if in your position.

 

[Despo1998]