First decide if you want to take a shower valve repair yourself, or contact a plumber. If you decide to repair the shower valve yourself, first you will need to shut off all water to the shower and tub.Next, turn the valves to the on position to relieve any pressure, and remove the set screws. Next, remove the trim ring and save all of the gaskets. Take all of the valve parts to a home improvement store where they will assist in finding you all the replacement parts. Lastly, you'll need to put everything back together in reverse order.
This will involve breaking open the shower wall, taking out the one handle unit and rearranging the pipework in order to replace it with a two handle valve unit. This not a DIY job, call a plumber to do this to save yourself the headache of having to call one later
You dismantle it from the front, find the problem and take the main part to Home Depot to find a repair kit. Then after repair, re-assemble in opposite way.
Though not a plumber, I can say that shower valves are usually made of brass(a very good material). Therefore they are also expensive to replace (50 dollars for the valve, 150 dollars per shower valve if done by a competent plumber). Therefore, when you notice a leak coming from your shower, try to replace the seat washer (usually the hot water side needs to be replaced first). If you still have a leak, it's time to replace the shower valve.
I don't know but I know a site that can help, the forum at Plbg.com
Replace the seats
If you mean shower valve, screws are for shower valve coverplate.
You replace it. If it's a squeal, you replace the shower head fist. If that doesn't make the noise go away, you replace the shower control valve. Odds are since you came online to ask how to fix it, you're not qualified to replace the control valve. Call a plumber now or call a plumber and a drywall contractor to fix it after you make your "repairs"
Behind shower valve handle and trim plate
If the noise is only for a few moments after taking a shower, its the expansion on the hot water side. Water lines going through studs will expand and make noise. the only way to fix this is to get in the wall and either loosen the pipe or tighten it with a shim.
Thermostatic shower valves are one of the most expensive parts of a shower. The current retail price for a standard one averages between $200 and $250.
You have to dismantle the control valve and fit new rubber washers. Instructions come with the washer kit.
Cut out the drywall in the wall behind the shower. Replace the valve. Patch the drywall.
This will involve breaking open the shower wall, taking out the one handle unit and rearranging the pipework in order to replace it with a two handle valve unit. This not a DIY job, call a plumber to do this to save yourself the headache of having to call one later
A leaking shower valve by installing a new cartridge.
depending on your spout diverter if its a valve or is it on the spout it self, if the diverter is on the spout then your diverter is not letting full flow of water out of the spout and its putting enough pressure to allow the water out of the shower head, I had this problem before and if you change the spout it should fix the problem. If you have a 3 way valve which is on the wall then i would suggest replaceing the parts in that valve if possible other wise change out the divert valve. If your broke like me and want a cheap fix then put either a water flow resistor or a shutoff right before your shower head.
You can call a professional in your area to come fix your shower or do it yourself by following a tutorial. How you fix your shower depends on what it is made out of such as fiber glass.
You can't . -Buy a new one, they are cheap.