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2017 Caterpillar 420f2it

Jhernandez940

Member
Joined
Dec 29, 2023
Messages
23
Location
Midland,Texas
I have a 420f2it with a quick connect pin problem. When I hit the lock button the bucket tilts forward, the pins don’t engage. Also the loader valve/right joystick doesn’t tilt forward
 

ahart

Senior Member
Joined
Nov 7, 2020
Messages
1,115
Location
Indiana
Start with a serial number so we can access the correct information, electrical/hydraulic schematics.
 

ahart

Senior Member
Joined
Nov 7, 2020
Messages
1,115
Location
Indiana
I think if it were me, I’d be looking at the compensator spool valve in the auxiliary valve and checking it for sticking. There is a magazine about replacing for a separate issue. In first picture which is a drawing of the aux valve, the center control valve marked “1” is the compensator spool. Second picture is hydraulic schematic showing how the two circuits are linked together.
IMG_2250.png

IMG_2252.jpeg

Keep in mind, this is only a theory as I have not personally experienced the issue you’re having with the machine you have.
 

Jhernandez940

Member
Joined
Dec 29, 2023
Messages
23
Location
Midland,Texas
After getting my own copy of the manual I noticed the aux valve hoses and tilt valve hoses were crossed. Everything works on the joystick now. Even the thumb roller. Do you know what exactly the thumb roller does?? Does it control the same aux valve to the quick connect pins? The unlock/lock button doesn’t seem to be working anymore. When I pressed the unlock/lock button before it sent a signal to the solenoids and you use to hear the valves actuate. Now nothing
 

ahart

Senior Member
Joined
Nov 7, 2020
Messages
1,115
Location
Indiana
The thumb wheel controls the aux valve for tool control. I’m not sure how swapping hoses caused the quick coupler solenoids to not function, what’s the story with this machine? New to you?
 

Jhernandez940

Member
Joined
Dec 29, 2023
Messages
23
Location
Midland,Texas
I picked it up at an oilfield auction. The backhoe part of the unit works fine, just been having problems with the loader. Does the switch use the same aux valves as the thumb roller or different set? I’m not sure how swapping hoses messed anything up
 
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