Have a shower only no tub. replaced both the hot and cold stems because shower was dripping and water pressure was low. Thought if I replaced the water pressure would return. Tightened the top nut before assembly, not sure if I was supposed to do that. Water doesn't drip but water pressure still low.

Is the hot water pressure good at other fixtures in the house? I'm guessing your newer valves have a scolding adjustment that is set very low. Check the instructions that came with the valve assembly.

Debris can get into the shower body/cartridge. Pull out the cartridge and flush the shower body and clean out the cartridge. Sometimes you need to replace the cartridge.

Price Pfister 1-800-732-8238

remove and turn cartridge 180 degrees then re-install

Hello
Take the plastic knob off.Turn the brass stem with a pair of pliers until you get it in the proper position.

Off faces down
Cold faces left
Hot faces right

Once in the position screw pastic knob back on.

The cartridge has 2 or 3 o-ring type seals around it that feed the water through, it picks up both hot and cold and mixes them. Some cartridges are replaced as one, some you have to replace the seals, just take the faucet info to the hardware store and match it up. I think the diverter is for the shower. It sends the water up instead of out.

Sounds like the valve is defective. The supply to the stems was not bored out at the factory giving you a valve that is essentially pretty on the outside and solid on the inside. To test it, uninstall the valve. Remove the stems. Then try running a pipe cleaner though the valve from the supply side and see if it stops before the stem.

First determind what side is dripping(hot/cold) then turn off water to entire house unless you have separate shutoff for shower behind wall. take a screw driver remove handle then use channel lock pliers to remove stem on the bottom side of the stem there will be a screw with a rubber washer on it you must remove the screw and replace the washer them re assemble Oh go to home depot and buy a the assorted pack of washer for faucets and stems find one that fits the pack cost about 4.99 best to change both rubber seal washer on hot and cold sinc e you have the water off

sounds like you may have a little debri on hot side stem or kinked hose between valve and spout turn off water to house remove handle pull bonnet and remove stem turn water back on with stem removed see how water flow is be careful turning water on you could make a mess i am assuming the low pressure is in shower only