I updated the bathroom but left the tub fixtures as they were, knowing I would need a plumber. I tried to do what I could. The old overflow cover’s lever no longer remained either up (to hold water in the tub) or down (to drain). This is a simple fix any homeowner can do, especially because the drain itself was in good shape. The overflow part is sold individually for about $10 at most home repair stores and requires few tools. The old cover is unscrewed and when it is pulled forward, the old lever’s attachment pulls the linkage mechanism forward also. A clip on the new overflow connects the new lever to the existing linkage. The new overflow is then screwed into place.
The diverter I tried to replace myself but the old nipple had to be rethreaded. Given that, swapping out the spout is as simple as unscrewing the old one and screwing on the new one. An adapter is included with most diverters to suit most plumbing.
The faucet itself is a bit trickier. I knew to shut off the water and unscrew the old handles and the collars. From there it took a plumber, who removed the valves within and replaced the whole thing with a new assembly. It is very important here to either replace the unit with the same brand or be prepared to pay for replumbing to retrofit a new brand. I guessed, after living with my dad, that the old one was most likely a Price Pfister, and bought that brand for the plumber to replace.
The whole thing needs cleaned up a bit, but here are the before and after shots.