. MAINTENANCE MAINTENANCE PROCEDURE METHOD FOR RELEASING INTERNAL PRESSURE IN HYDRAULIC CIRCUIT WARNING CAUTION 4 - 43 Th e hydraulic system is always un der internal pressure, so when inspecting o r replacing the piping or hoses, always release th e pressure i n the ci rcuit before st arting. If the pr essure is not released, high pressure oil may spu rt out and cause serious persona l inju ry. Th e par ts and oil are at high temper ature after the engine is stopped, and may cause serious burns. Wait for the temperature to go do wn b efore sta rting the ope ration.
When th e oil f iller cap is removed, oil may spurt o ut, so turn the cap slowly to release the pressure before removing the cap. When the e ngine starting switch is at t he OFF positio n, power i s not supplied to th e control valve (PPC valve). Hence the residual pressure in the h ydraulic circuit canno t be released, e ven if the work equipment c ontrol lever is moved to the full stroke. Be sure to tur n the engin e startin g switch ON, when releasing the resid ual pressure in th 1. S et th e machine o n the flat an d firm ground , and the n stop the ngin 2. T urn t he st arting s witch to the ON position. 3.
Within 15 s econd s after stopp ing the engin e, turn th e starting s e p witch to th e ON p osition, and operate the c ontrol le vers (work quipment , travel) fully in each direction to r elease th e internal ressure.