mend 作为修理，名词就是mendmending在英语里有其他的意思，参考柯林斯字典：mending
词义： Mending is the sewing and repairing of clothes that have got holes in them. (OLD-FASHIONED)mending的意思是缝补衣物 ---------------------------------------补充：可以用to be mended (ment不是mend过去式)
need doing 是被动，某物需要被怎样，比如 The desk needs repairing.need to do 是某人需要做什么，比如 I need to do the homework now.以上两种情况下need都是行为动词。need做情态动词时后面不跟不定式而是直接跟动词原形。 I need look after the kid. 所以你问的问题属于第一种情况！
