jerky loader hydraulics

[jcimob]

YM155D with loader. No problem up until winter weather, now experiencing jerky slow hydraulics on loader. Symptoms are worse the higher the bucket is elevated, lower down is not as bad. Have cleaned hydraulic filter and changed out the oil.

any ideas on what I can look for next........do I need to try and bleed air out or something?
thanks
Frank

 

[MJPetersen]

Make sure all hydraulic connections on the suction side are tight, clean, and air proof. Hydraulic pumps do not suck well and the thicker, cold oil will max it out--therefore, if there is a loose connection or a cracked suction line it will draw in air rather than oil. There also is a seal on the pump shaft itself that is a possible culprit. The system will take the path of least resistance!

You do not need to bleed out air--it will self bleed after a few cycles.

Mike

 

[CAT793]

What grade oil are you using ??? how cold is the weather ??

 

[lens12]

If it is below freezing , you probably have moisture in the oil which is freezing & plugging the hydraulic screen.