5 Maintenance 6. Loosen the screw plug (2) of the hydraulic oil tank and let the oil run off. 7. Open drain valve (3) gradually to drain the oil. 8. After draining the oil, close drain valve (3). 9. Re-tighten the screw plug with its seal being in perfect condi tion. 2 10. Unscrew the venting filter screw (1). 11. Fill up oil until the oil level is between the centre and top edge of the inspection glass. 12. Start up the engine. 13. Raise and lower the work unit several times, while operating the bucket at the same time. 14. Lower the bucket onto the ground and bring it into mining position. 15. Check the oil level with the engine running idle in its low speed position. 16.
Ventilate the hydraulic oil tank (see section "Ventilating the hydraulic oil tank" on page 5-70). 3 NOTE Do not fill up with too much hydraulic oil! Otherwise, the pressure in the hydraulic oil container increases inadmissi bly high. Ventilating the hydraulic oil tank 1. Loosen the venting filter screw by turning it a couple of rota tions. 2. Start up the engine. 3. Bring the boom into its highest position. 4. Bring bucket into its tip-in position (up to its limit stop). 5. Re-tighten the venting filter screw. 5-70 WA90-5 – VEAM270100 1