4x4 vaccum seal problem?

[cntryboy17]

I called and inquired about a truck im considering buying the guy said that the only problem is that the switch for the 4x4 was disconnected and that he didnt know why, but im thinking that its because something with the vaccum seal has a problem and he wanted to bypass that system and just do it manually, the guy said that the 4x4 engages you just have to do it manually. Should this be a concern? or will i be fine by just manually locking them in? will replacing the vaccum seal lines be pricey or hard to do.