What you need to do is buy a replacement (new) cost is relvantly cheap. the correct brake fluid in aust it is known as dot 3 don\'t use any other even the multi dot 3/ 4 is no good for rubber seals. place a line lock on rubber part of hose so you don\'t loose the fluid from master cylinder . remove old unit by undoing the banjo bolt which carries the fluid first then the location bolts. replace new unit in reverse order bolted on then the fluid bango bolt with the washers to seal the fluid . after fully bolted back in undo the bleed nipple on the slave cyl then remove the line lock, keep the resvoir full with new clutch fluid . let the old fluid gravety feed out of complete unit , remembering to keep res full once new fluid is coming thru , tighten the bleed screw and get some one to help you bleed the unit properly . very easy job to do and quite common as the brake fluid is hydrascopic meaning it absorbs water , the water goes to the lowest point being the slave cyl. it is recommended that brake fluid and clutch fluid be replaced yearly due to the hydrascopic nature of it and it is the water that damages the seals and surfaces which then fail just as yours has . hope this helps mate