Top 10 Moen & One Handle Tub & Shower Faucet Questions & Answers

the cartridge if defective,replace it and your leak will stop.

It would be an allen wrench. Any typical multi sized wrench should have the proper sized allen wrench.

The holes can often become filled with grime so be sure to seat the wrench properly to prevent stripping.

I believe it's a 3/16ths or a 6mm. metric.

sounds like the pump is broke. better off just replacing whole unit unless you order new pump from triton.

The exact procedure to remove the old cartridge is with a plastic removal tool.With replacement cartridge you have to buy this plastic removal tool.Also there is same metal removal tool available.With the help of this tool you can easily remove the old cartridge.
Moen Cartridge Replacement Instructions

Moen shower faucet cartridge replacement is a project that will take some time to get done right. When is it time to replace a Moen cartridge? If you are like most people, you won't want to replace your old Moen cartridge until your old cartridge is starting to show its age.

Replacement is necessary, usually, once the old faucet starts to drip. Thankfully Moen faucet cartridge replacement is not difficult. However, if you are uncomfortable with doing the repair yourself, do not hesitate to call a professional plumber to do the job for you. This will guarantee that the job is done right.

If you follow these Moen faucet cartridge replacement instructions you will be able to replace your old cartridge by yourself. First of all, as with any plumbing repair, make sure that the water supply is turned off. Open the faucet to remove water pressure from the lines and let the remaining water drain from the pipes. You will then need to remove the faucet's handle by removing the decorative cover and removing the retaining screw. This will allow you to remove the handle.

Once the handle has been removed, work on releasing the splash plate from the wall. Generally there will be one or two screws to remove and the plate should release from the wall easily. From here the process begins to get a little trickier. Insert a shower stem socket onto the faucet valve's retaining nut and release the nut. Your Moen cartridge removal will be complete once you grab the cartridge with a pair of pliers and pull straight out to remove the old cartridge.

Clean any surfaces that you have access to and replace with the new cartridge. Follow all of the previous instructions in reverse order to re-assemble your shower faucet. Check to make sure that all the connections are tight before turning the water back on and testing the system out.
Now in your case the broken/cracked while removing the old cartridge so try this procedure carefully to get the stuck -up old cartridge out.
TAPPING the Threads into the Cartridge:
Carefully  hold one tab on the cartridge tight against the brass lip on the faucet body with needle nose and try  to drive the 1/2" tap into the smaller bore of the cartridge. It will take  about 15 minutes to slowly work the tap in all the way (maybe 3 turns?). Then  back out the tap... remove needle nose. [remember to turn the tap 1/4 turn back, for each 1/2 turn forward ... this clears the metal particles from the tap and makes the next 1/2 turn forward go smoother].

Next, assemble a 1/2" x 4" threaded rod, so it had threads all the way to the two jam nuts on one end)... If you use a bolt, get one with threads all the way up to the head. you may find it hard to find - so try a carriage bolt and spin a nut all the way up to the head .... continue: 

next on the bolt goes a 1/2 nut (this is the "jacking nut") and a flat washer so the jacking nut can spin easily against the next piece, a 1/2 drive socket (7/8" ) with the square hole toward the washer and jam nuts ( bolt head ).
The open end of the socket faces the brass body of faucet and rests on the round brass lip... having the same inside diameter. This allows a space for the cartridge to be pulled into ( a cavity). Thread the bolt into the tapped cartridge and snug it up so the 7/8" socket is aligned with and resting against the brass body. If the cartridge spins smooth, the threaded rod is GREAT. You can just work with the 1/2" rod and use needle nose (or similar) to stop the  cartridge from spinning, to get the rod threaded into the tapped threads in the cartridge... then, slip on the socket, washer and nuts.

Now snug it up tighter. Check socket alignment. Then begin turning the jacking nut ( the "extra" nut) until it contacts the flat washer and 7/8" socket. Now, as you continue to tighten the jacking nut, it will pull the 1/2 bolt (threaded rod) away from the faucet... and the cartridge will come along too. [You have to prevent the 1/2 rod from spinning while tightening the jacking nut. put a wrench on the bolt head.]
This procedure is bit lengthy and requires some appropriate tools,but this will release the stuck cartridge out.
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here is a web site with the original wooksheet that came with your faucet. All replacement parts are listed as well. Home Depot will stock your item if needed
http://homeappliance.manualsonline.com/manuals/mfg/moen/2300_series.html

You need to replace the mixing valve. It's not terribly hard to do, if you have some tools and, if the valve is not stuck in the fixture. Here's a video on how to replace it. Take note of how the tabs on the valve are positioned so you can put it in the same way it came out. If cold and hot water are reversed, you need to take valve back out and rotate 180 deg. and put back in:
http://www.youtube.com/watch?v=J-SNBNijfQc
Dave
This is assuming you have hot water elsewhere in the house and not ot the shower. Check to make sure you have hot water at other faucets.

hi mike:) do you mean the tiny little hex bolt which holds the tubspout in place or the handle?

Try removing the screw in center, and pull handle off. Check to see if maybe just inside of handle is stripped, or if it has a plastic insert with splines that are stripped. Thus just replace handle or insert or both. You can try turning it with vise grips or pliers carefully when handle off to see if tap itself is still good. My guess is a replacement handle and/or insert and you'll probably be good to go. Any hardware store should stock parts, reasonably priced.

Wow the post says can't get handle off even after set screw is removed and the advice given is, it's an Allen screw, duh he got it out but the handle is stuck. Pull off the handle there are limiters behind it, his problem is the handle genius not water temp.