Skidsteer slow hydraulics

My new holland l454 skisteer developed really slow hydraulic
lift and bucket movement. The hydraulic charge light is
coming on. It drives just fine though. I recently changed
wheel seals and and it has new filters and fluid. It doesn't
appear to be cavitation g. I see no bubbles in the fluid. I know
they have 2 pumps but was unsure if one operated functions
and the other wheels? Any help is greatly appreciated.

I don't know that particular model machine very well, but I took a look at the parts book for one of them to get an idea what you had. Given what I saw in the parts breakdown as well as what I have seen on other machines over the years I will say this.

The hydrostatic drive system is basically a stand alone system beyond the charge pressure applied to keep it 'full'. Basically you've got a pump to drive each side, and they are stacked end to end. Typically the hydraulic pump is coupled to, and drives off of the back end of those two hydrostatic pumps. Based on the parts breakdown that's how yours is set up. In operation it will often provide flow for both the hydraulic system, as well as charge pressure for the hydrostatic system. Some machines separate the two functions, but based on past experience I'd make a guess yours is doing both.

If that's the case, then it sounds like the gear pump that's supplying both functions is worn out and bypassing pressure internally.

If the link provided works it should show you at least one option out of the parts book. In any case it should be either page 030 or 041, depending on serial number.

That all said, the only way to actually check the pump is using a flow meter with a guage and a way to put a load on the pump. Basically the pump can put out the correct flow until pressure is needed, but drop off flow dramatically when a higher pressure is necessary. This sounds to me like what's happening in your case, and it's symptomatic of the pump being worn and bypassing internally.

Hope this helps, and good luck.
Poke here

Can this prob develop in a short time. It worked fine then I added oil because it was low and less than 20 min of operation it went from fine to lifting really slow. Even the down operation of the arms is slow which seems odd if there is weight on it. Could there be a suction filter in the tank? Could this restrict flow?

Sorry for the delayed response back to your second question.

You shouldn't be having the problem I described over that short of a period of time. Usually pump wear comes on a little at a time, until it gets noticeable enough to cause a problem.

That said, I've looked at the parts sheets again, and can't find anything on an in tank strainer, or anything else, beyond the standard hydraulic filters, so you shouldn't be having a problem in that regard.

About the only other thing I can think of, off the top of my head, is that maybe the added oil, and exiting oil, weren't compatible. I have seen this happen and cause the oil to foam. Once it foams and gets air entrained into the hydraulic system, it will act really stupid.

I did see a solenoid valve on the hydraulic system, that appeared to be on some machines, that looked like it locked the hydraulics out unless the safety devices (seat belt, lap bar, or whatever) were engaged. Usually that kind of setup won't allow the hydraulics to do anything, so I don't think that would be your issue. Still it might be good to check in case the solenoid is only getting partial voltage to it, and pulling the valve halfway open.

Beyond that, it' hard to what the problem is, and I'll admit I'm pretty much lost without actually laying eyes on it.

Hope this helps. Wayne

The equipment hydraulics is completely independent of the drive system though they do share the same oil,the hydraulic pump is a gear type pump,oil pressure from that pump goes to the control valve and is diverted from there to an equipment function,as it is highly unlikely that all the cylinder seals fail at once it is fair to assume that either the pump is not up to par or the oil is escaping internally,the most likely place for that to happen is the main regulator valve,you will find it in the equipment control valve bank,if the o'ring on the valve body fails or the relief valve is stuck open the oil can escape back to the tank rather than move the equipment,that valve is what I would look at first,screw the whole valve out so as not to alter the settings,check to see there is nothing holding the valve off its seat and that the o'rings are ok,do have the equipment secure and wobble the levers about,does your machine have any electric controls for add ons if so check to see they are in the right position,I have assumed that the control linkage is working properly and the control valves are moving the proper distance.
AJ