Case 580 ck slow cranking

[Case450]

I been having a hard time getting my backhoe to crank proper. It cranks slow like the batteries are weak. I replaced all the cables (its 2 - 12 volt batteries in parallel) and tried 2 new oversize batteries just to crank it and it still cranks super slow. Like wont start slow.
Time to rebuild the starter??
I cleaned all the contact points because I thought weak connections was why but bare metal and clean copper contacts.

 

[tractorsam]

Are you sure there?s no extra load on the engine and thus the starter such as the hydraulics or something in the transmission dragging? Also have you measured the voltage at the starter while cranking?

 

[Case Nutty 1660]

Stater would be my first guess, if you have removed the backhoe you do have the hyd lines plugged back into each other in a loop correct,, I have seen them cause a dead head condition and they will crank slow but almost start good thing they do not as you will blow the hyd pump if they do start with the line blocked,,