Repairing a single handle Valley shower leak is a fairly easy project. Single handle Valley shower valves are relatively common and the repair parts are, therefore, not hard to find. The repair for a Valley shower is fairly similar to that of the old style single handle Valley faucet.
When you have a leak in a Valley shower valve there are a couple of possible repairs that will stop the leak. The first and least expensive is to replace the seats and springs inside the valve. If this does not repair the leak, the next thing to do is to replace the cartridge. The seats and springs should always be replaced when changing the cartridge anyway, so doing that first is part of the process and may save you the cost of a new cartridge.
The first thing to do is to shut off the water to the house. Drain any water remaining in the pipes by turning on the faucet in the bathroom sink.
Remove the Handle
When the water is off and the pipes are drained you can remove the shower handle to access the valve components. Lift the handle so it is in the on position so you can see the screw that holds the handle in place.
Using an Allen wrench, loosen the screw and slide the handle straight out. You should not need to remove the screw all the way to get the handle off.
Remove the Bonnet Nut
Now remove the brass bonnet nut that holds the cartridge in place. This can be done by using a big pair of pliers to unscrew the bonnet nut.
Position the pliers on the uppermost part of the nut threads otherwise, the nut could bind while you squeeze. Be patient, this part can be a little difficult. If it does not come off easily apply some lubricant to the nut and let it sit for a few minutes before continuing. Don’t try to force the nut.
Remove the Cartridge
With the nut removed you can take out the shower cartridge. This step can be a little tricky and must be done carefully if you mean to save the cartridge. Use a screwdriver on each side of the cartridge to wedge the cartridge out.
On the side of the cartridge, there is a nipple that sticks out to the side. A screwdriver wedged under that nipple can work the cartridge out. The cartridge should pull straight out once it is loosened.
Remove the Seats and Springs
After the cartridge is removed you can see the seats and springs at the bottom of the cartridge chamber. The rubber seats get hard and the springs get worn out and stop working properly. The seats should be changed whenever there is a shower leak regardless of whether you change the cartridge or not.
Use a screwdriver to pop the seats and springs out of the shower valve. Each seat has three parts, the rubber seat, the spring, and the white insert. Make sure to remove all three parts to clear the way for the new ones.
Install New Seats
The new seats and springs are installed just like the old ones were removed. The plastic insert goes into the spring on the bottom and the rubber seal goes on the top. Both seats and seat openings are the same.
Slide the three pieces onto a screwdriver to keep them in position while you push them evenly into the slot in the shower valve body. Push them into place all the way down with your finger. They should stick up just a bit but spring down when you push on them.
Reinstall the Cartridge
A new cartridge is installed just like the old cartridge if you decide to try and reuse it. Before you put the cartridge back in place it is a good idea to lubricate the O-ring with silicone grease.
Line up the nipple on the side of the cartridge with the corresponding slot in the shower valve body. Insert the cartridge straight down into the valve.
Reinstall the Bonnet Nut and Handle
Screw the bonnet nut back into place. The bonnet nut should be screwed on hand tight only. As long as the cartridge was pushed all the way into position the nut will just hold the cartridge in place.
Lastly, reinstall the handle and tighten it with the Allen wrench. Turn the water back on and check for leaks. As mentioned if by chance your valley shower still leaks after replacing the seats and springs you will need to replace the cartridge as well.
Note: If the bonnet nut was difficult to remove, put some silicone grease on the nut threads so it will come off easier next time.