I have powerful hydraulic action with my end

Best advice is for you to list this in Lawn and Garden or Construction equipment section for Tractors. There is a valve knob on a 4000 series that proportions hydraulic flow from more in back than front depending on the setting. If you have a front loader or if you have rear attachments you can get more action on the end you want. On a 4000 the knob is by the right heel of the driver. Could work like this for 7810.

hydraulic pump not working
filter to the pump blocked
valve stuck open

basically there are 2 points of control
1---is the control valve for that side which may not be opening the system
2--- the drive motor for that side which may be passing excessive oil and not turning
for the lift action to be slow indicates excessive pressure leakage in that circuit
early units had lever action to the control valves where as later units use electronic controls from joysticks to operate the valves
If this is your type of machine, I would be looking at faulty electronic control mechanisms or corroded wires and contacts

Springs, or valve seats in the control valve need repair. Or at least my wild guess, with some understanding of hydraulics, in general.

Bummer deal! You may need to use a product from Mega Power to clean and free the units hydraulic sticky valves that tar up when cold. You're right, new fluid is not meant to be potent. You simply add this valve treatment to the fluid. Results are fast - like under 45 minutes in a grader it was installed in. This product uses chemical cleaners that work like penetrating oil - not solvents like part stores and supply places sell. Try the link below, but what it says for transmissions apply 100% to your hydraulic system. My son uses several diggers and tractors in his commercial plumbing business. Once he got on to Mega Power benefits he found it best to start adding Mega Power to his new equipment engine transmission and hydraulic systems - as Mega Power keeps those valves, gears, and pistons clean in a dirty environ he claims. He never has had downtime repairs for sludge or wear out since he started adding this product. This may be the easiest and cheapest way you will find to end your cold operation. Of course, you can pay a mechanic to take apart and hand clean those sticky parts as a fix. Mega Power ends transmission jerk transmission converter lock up jerk

1st ck hyd tank for fluid level and fluid quality 2nd remove and ck hyd filter for blockage (note some hyd filters have a water sensing block valve inside) 3 rd verify that fluid is reaching pump , pumps will make horrible noises with no fluid in them , if all are well replace pump , and ck that bypass valve is not stuck open and is set correctly (some are internal to pump )
a method i've been sucessful with is to temp power hyd system with remote from another working tractor/bobcat , this sometimes unsticks bypass valves , but unless your familiar with what fittings do what and such I don't recomend this action for novices

You may have to take the bottom of rad. loose so you can belt in. Sure be able leave hoses connection.

check with Central Tractor or Tractor Supply as they do have tractor manuals

jim

It looks if there is a pressure relief valve on the pump as I can see on the picture? If your problem isn't solved yet, please give me the pump manufacturer and type or the hydraulic scheme.
Kind regards Marcel van ****

Open bleeder at slave. Push down on pedal and hold. Tighten bleeder and repeat until fluid is present. Then pump up and bleed remainder of air. Requires two people.