Step 5: As stated above, the keyway in the temperature limiter prevents the hot water from being turned up too high. In the case of this particular faucet, the piece had somehow rotated one or two notches clockwise and simply had to be rotated slightly counter-clockwise and put back in.
Rotate the temperature limiter slightly counter-clockwise and push it back in. The keyway will now allow the faucet to be turned futher toward hot and allow more hot water to mix with the cold water, raising the temperature of the shower.
A before and after picture showing the postion of the temperature limiter is shown below. The picture on the right shows the limiter set to allow more hot water.
Another view is shown below.
Step 6: While you have the cover off, clean up any mold or dirt which may have collected on the surface under the cover. The gastket on my cover had deteriorated after many years of use and had a bunch of gunk underneath it as well. Wash off the cover as needed and apply a bead of caulk on the cover as necessary.
Step 7: Test before you put everything back together. Put the knob onto the shaft - you don't need to screw it in - and test to ensure that the water does get hotter and that you can turn the water off all the way. The knob should rotate freely.
Step 8: Put everything back together in reverse order of how you took it apart. First push on the temperature limiter. Then put the decorative main cover in place and screw on the chrom retaining ring until it is tight enough to hold the decorative cover against the shower wall. Then put the knob back on and secure it with the phillips head screw, making sure you don't overtighten it or you could strip the shaft underneath. Then put the temperature indicator ring and the decorative cap on. Wipe up any excess caulk which may have sqeezed out from the edge of the cover.
Step 9: Enjoy your hot shower.