Inside the tank are two bolts holding the tank on to the base. Unscrew these two bolts and carefully lift emergency service the tank from the base. Remove tank to the trash.
Examine the washer and replace it with a new one. Also replace screws in water line repair case they are old and damaged too. The new ones you buy should be durable and of good quality.
After you have the stems out you should be able to find the washer on the "inside" end. If it is nicked, torn or brittle it is likely the cause of your drip. Even if it looks brand new, go ahead and replace it. You've already come this far. You can get replacement washers at almost any hardware store. Sometimes you may want to replace the whole stem, especially if the handle end is stripped out. It's best to just take the stem with you to the store and see if you can match it up. Most Do It Yourself stores have replacement stems for many popular brands. If your valve has a center diverter valve to switch the waterfrom the tub spout to the shower head the same process applies. Many times it is easier to replace the diverter stem than to repair it. This really depends on the design of the stem.
Service magic only let's licensed and insured tradesmen advertise on the site so that would be a great place to start. I would recommend getting at least three different quotes from different companies. This way you have an exact price of how much your works are going to cost and you will know exactly what you are getting for your money. You will also get the very best price for that work. Most plumbers will often try and sell you work that maybe you don't need as they are trying to make a living.
Plumbers, like all other companies, are required to be on time and act professional. If they have called before hand to notify you then, this can be overlooked. However, if they turn up without apologising for being late, then they may not be the right plumber for you. Remember first water line repair impressions are everything. If they lack a good first impression then this may indicate that it is going to have an impression on their work. In most cases, you would have taken the time off work for the plumber, and what can be worse than waiting all day waiting for them to arrive?
From your own point of view, it is important that the plumber be trustworthy and credible. Ensure the plumber comes with at least two strong references which you can verify. This will help you be more secure and suffer less anxiety.
Then, you can take your new shower parts home and reinstall them in the inner assembly. It is very important that everything be aligned properly and tightened to prevent leaks. Beware of over tightening, however, since this can also cause problems. Once you are sure everything is installed properly, replace the cover plate and turn the water back on to test your repair work. With a little bit of work, your do-it-yourself shower repair project can be a success. It does not take an expert, just a little effort and know how.