SM lift arms twitching

[Kre1979]

Hi all,

When my sm link arms are right up with pump running the arms twitch up and down, what would cause this?

Kev

[Brian]

This is normal. When the piston is right out and it contacts the "Knock Off" pin it causes the linkage to the control valve to move.

It should stop if you move the control lever slightly.

[Kre1979]

Hi Brian

Drove her home yesterday from where it's stored, tried moving the lever down a little only really stopped twitching when it was near the ground. When fully raised you can see the plough twitching and hear the pump surging slightly when the arms twitch.

Kev

[Brian]

Then you have a leak from the ram cylinder seal or a control valve/check valve leak. Pull the aux service knob out, if the lift stops dropping your fault is control valve or check valve, if it still drops your fault is piston seal or "O" rings on the ram cylinder or possibly ram cylinder safety valve.