Well, in my case, the level sender had conked out and volvo told me (and my mechanic) that the sender was $250.00, but that because of an upgrade in design, I'd have to buy both pump and aparratus for a total of $500.00. I found a junk aparratus for $15.00 and used it as a model to repair my stock unit. The junk unit was missing a short section of hose. I was curious as to why someone would take that cheap little hose and leave the much more valuable sender unit (it was the only one in the whole junkyard).