Cat 420E

[Dwilliams]

Cat backhoe 420E. Serial number C4E06212. PIN: CAT0420EVPRA00699.
Problem: When using joystick to tilt bucket forward, without warning, the bucket tilts all way forward, rapidly, and joystick loses control. When bucket stops, fully tilted forward, joystick will not work to tilt bucket back. To regain joystick function there is a short "lever-like" device on right side of backhoe, in front of cab, outside engine side-panel sheet metal. With bucket malfunction this "lever" is moved forward from its normal position. I take a block of wood, place on front surface of "lever", hit wood block with big hammer and "lever" moves back(toward windshield) to correct position, then joystick works again.
I cannot determine function of the external "lever" and need to learn how to correct problem. Besides aggravation. uncontrolled forward bucket tilt is safety issue. Joystick often has a "catch" in it when moving bucket so I am suspecting there is a connection to bucket tilt problem.
I am a farmer, hoping to find help to fix problem and avoid having to load, transport and pay Cat dealer for repair.
Thanks for any help anyone can provide.
David

 

[Mark250]

would this be it

 

[berky]

Sounds like something is binding up in the mechanism or it is worn so much that it is causing it to bind. Might just need lube. Take it all apart clean and look for the culprit.

 

[Dwilliams]

Thanks for the message. Item #14 in the drawing is what is hanging. I will lubricate and see if that fixes the problem.
Thanks for your help.

 

[Cmark]

To answer the question of what it's all for, it's a levelling mechanism designed to automatically tip the bucket slightly as the arms reach the top of their lift. Without it, material would spill out of the back of the bucket and you would end up with a cab full of cow sh1t.

 

[Billrog]

David not familiar with your machine but that has something to do with roll back so you don't dump the load back on your machine and for some reason it looks like #14 the cam is going past center . Check for some kind of adjustment.

 

[Dwilliams]

Understand purpose function. Today I accessed linkage from bottom of joy stick to cam rod. Tomorrow I will clean, lube, reassemble and check for adjustment.
Appreciate your help.
Thanks