8. Pofuna kupewa kuwonongeka kwa zida zomwe zimadza chifukwa chakuchulukirachulukira, pali valavu yotsitsa yokhayokha mu chipangizo cha hydraulic. Pamene chinthu chokoka chikudutsa katundu wovomerezeka, valavu yowonjezera idzatulutsira, ndipo chokoka chophatikizira cha hydraulic chokhala ndi tonnage yayikulu chimagwiritsidwa ntchito m'malo mwake.