So i have a L4630 and the hydraulic pressure is only 1500 psi, it should be 2500-3000 ish psi. The dealer said the pump was weak so i replaced the pump and no change. They then said it seem fine to them. Any advice on what it can be?
L4630 low hydraulic pressure
- Thread starter Jimmy2009
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North Idaho Wolfman
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Hydraulic pressure gauge, and have checked at loader valve and remote valve.
TheOldHokie
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Do you have an actual operational problem or are you just curious?
To measure pump outlet.pressure on that tractor shut tje tractor off, disconnect the inlet supply hose on the loader valve, and connect the gauge directly to the end of the hose. Start the tractor and run it just long enough to read pressure then shut it off and reconnect hose. If pressure is low its either a problem with the pump or the main pressure relief valve.
Dan
The loader wasnt lifting like it used to, and other attachments weren’t working properly. I have verified from Kubota that pressure should be at least 2500 psi at idle. Replaced pump, per Kubota, no change, changed main relief spring, popet, and spring seat, still no change. Only 1500 psi and any point.
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
I have a hydraulic pressure gauge and have checked at the the loader valve. Unplugged a hose. Installed pressure gauge, and started tractor and operating that function, then also did the same thing at the remote valve.
TheOldHokie
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Screw the pressure gsuge directly onto the pump outlet port on the tractor's hydraulic block. Record pressure at both idle and max RPM.
Dan
Dan
TheOldHokie
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No - that eliminates the relief valve and you are not equipped to do that correctly and safely.
You need to hook into the pump outlet port on the loader outlet block that replaces 020. Post a picture of the current connections for help identifying the correct port.
Dan
TheOldHokie
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Top right hose in first picture. Disconnect the hose and connect the pressure gsuge to the fittung in the block. I would guess thst is a JIC-08 male nipple. When you start the tractor you will be deadheading the pump agsinst the relief valve and you should see that ~2200 PSI number.
Dan
Dan
TheOldHokie
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Excellent!!
Your pressure is a little low so the next step is to add some adjustment shims to the relief vslve and retest. Do you know how to do that,
Dan
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
You got it.
While the valve is apart inspect the sealing surfaces for foreign material or signs or wear/damage. I dont like the difference in pressures at idle versus max engine speed.
