Moen single handle shower faucet, contstanly drips

Sometimes the valve sticks to the handle, try spraying a little vinegar or delimer and let it sit a moment; then wiggle it loose.

you need to get a replacement cartridge moen Faucets have a tendancy to go bad you can lok up the part number at moen .com most faucets have a warranty if not the will ship a new one in about 3-5 days

It can be repaired without taking entire valve out of wall. First shut water off and remove handle. Next you will see a collar that will screw off to remove the cartridge below is a link for a single handle moen faucet. Check it out to get an idea. If you know your model you can research on line ,but they are close enough to give you an idea.
Once appart replace washers or o -ring's. Pay attention to how you take it appart for easy reinstallation.

http://www.moen.com/shared/pdf/t2703pt.pdf This link is aparts breakdown of a single handle faucet.

http://www.moen.com/shared/pdf/t2703pt.pdf This site is installation instructions.

http://www.efaucets.com/detail.asp?Product_Id=T2703 This site you can enter you faucet model to retrive information.

The old MOEN single handle faucets like youve described usualy took a 1200 or 1225 cartridge. Both are available at most of your big home improvement stores. The answer to your question is yes MOEN parts are still avail. Hope this helps. If this advise is helpful, please give me a vote.

the problem is in the shower fitting the part with the handle ,depends on who made it but you replace washers or a cartridge some times easy some times not

It sounds most likely to be a bad cartridge.

Hope this helps

tun off the water.
unscrew teh allen screw under neath the handle. pull out hteh handle. undo the wall plate and gain access to the cartridge in the handle body. turn the artridge around 180 degree and reisntall all parts.

if you have taken out screw then pull off if you have a handle puller use it

it is your shower cartrige. ace hardware $45. hot always goes first. just check if it is a posi-temp or moan trol

I need to ask a few questions to solve your problem.

What Model Shower body is it?
How big is the white plastic piece?

If it is about 6 inches around (just smaller than the face plate) and you are installing this shower body in a preexisting tub/shower, this piece can be discarded. It is a guide that is used so the tile contractor knows how much room is needed to service the valve once it is installed.

If this is not the case, just post with a few details and I'll modify my response.