Steps:1. Turn off the water supply to the tub. Open the valves and release the pressure. Loosen the nuts holding the hot and cold water supply tubes to the fixture with an adjustable wrench, then remove the nuts by hand (figure A).
2. Use the wrench again to loosen the nuts holding the fixture to the tub and remove the fixture.
3. Measure between the centers of the fixture and find a replacement that matches (figure B).
4. Clean the mounting surface on the tub with the painter's tool so the new fixture has a nice, clean surface to attach to (figure C).
5. Roll out a couple of beads of plumber's putty and place around the new fixture (figure D). This will seal up the gaps and prevent leaks.
6. Hand-tighten the bolts holding the fixture to the tub, then lock them down using the adjustable wrench.
7. Smear a generous portion of pipe compound on the threads of the fixture before reattaching the water supply lines (figure E). Hand-tighten the fittings to make sure they're not cross-threaded before tightening with the wrench.
8. Install the riser assembly. Rub a bit of dishwashing liquid around the edge of the washer on the riser before installing (figure F). This lubricates the washer and allows you to get a good, tight fit.
9. Apply pipe compound to the threads on the fixture where the riser mounts, then insert the riser and tighten the retaining nut (figure G).
10. Turn the water back on and test for leaks. Tighten around parts that leak.