This one; I need to tackle what appears a nigh on impossible job so seeking advice from those who have done it. Seems I'll need some flexible hose, what have others used? What is hose ID? I've tried to measure stub (access limited)and come up with 40mm. There are a few 38mm hoses else where which are much closer to 1 1/2" which is easy to find. Have I measured wrong? Tips?