770 dipper piston bent

[damammel]

Hi all. I'm usually in the Yanmar section. I'm trying to figure out why my friends 770 bh dipper piston keeps bending. She has used the tractor plenty but recently has been destroying the pistons. The first one bent slightly, the second one turned into an S shape and the third has a 45 degree bend. Is there a relief valve that may be stuck or clogged? I have removed the piston and the arm moves freely. She has done no maintenance to the tractor.

Also, is there a good place to buy new/used parts for this tractor online or near eastern CT?

Thanks for any thoughts on this one.

 

[damammel]

Just bumping this up to see if there are any suggestions. Thanks