Eat a bowl of Wheaties and lift. It will will only stay lifted when its all the way lifted and the highest piece will be quite high.Remove the nuts inside the front uprights of the cab(one on each side). Then lift the front of the cab up and over center. The older 743's had springs on the pivot shaft and the newer one had gas shocks to help raise it. If the bucket is not on it you'll need to put jack stands or blocks under the rear of the machine to prevent the weight of the cab from tipping it back on it's butt.
saftey stop probally shot as well use a comealong to secure, and heed jack stand advice , this can be real quick way to get hurt. or pee youreself,Eat a bowl of Wheaties and lift. It will will only stay lifted when its all the way lifted and the highest piece will be quite high.