MapleGrove
Member
I have a Komatsu PC35 mr-2 with a boom down function that is weak and blade drift but only when boom function is down. For example boom will not lift machine up without using another function and after controls are released it will not hold in position. Blade will lift and hold machine until boom is moved to down function and it will drift, no movement in up function. If maxing out a cylinder function such as bucket curl in, dipper in and blade down the boom drifts up on its own. Problem started when I serviced hydraulic system and strainer. Everything was fairly clean, replaced hydro fluid and started machine back up. Boom would not lift itself up. Prior to service all functions were operating normally. Finally able to get boom up enough to drop off at mechanic 1. He got machine functioning but this is when current boom and blade problem arose. Dropped off to mechanic 2 and he ran pressure tests and said entire main valve body needs to be resealed to about $2500 plus removal and install for shop time. Cannot get a hold of mechanic 1 because he moved and would of liked to ask what he did to get machine to current operating state such as switched hoses or adjusted relief valve pressures. My ultimate question is does this sound as a possible relief valve/valves bypassing or damaged spools in main control valve? Sorry for the long post, I have been a guest for years before signing up and am amazed at the wealth of knowledge shared on the forum.
