Loose Support Arms -- Two-Piece Holders
One of the most common toilet paper holder models consists of two support arms mounted on the wall, and when one of these comes loose, the rod supporting the roll falls out. In most cases, the repair involves little more than tightening the setscrew under the loose support arm with a small flat-head screwdriver. When that doesn't work, it means the support arm's wall-mounting bracket has come loose. To tighten it, remove the arm by loosening the setscrew, and then tighten the screws holding the bracket to the wall. Spread some thread-locking paste on the setscrew before tightening it to prevent it from backing out again.
Stabilizing the Brackets
Many people use conical plastic anchors to secure screws to drywall when installing toilet paper holders, and these anchors have a tendency to work themselves loose. If that has happened, the best solution is to remove the loose anchor and replace it with a winged anchor, such as a toggle or molly bolt. This type of metal or plastic anchor may have threads like a screw -- in which case you screw it into the wall -- or it may be smooth, in which case you tap it in with a hammer. Either way, the wings spread out and lock the anchor against the back of the drywall, giving you a more secure holder for the bracket's mounting screw.
Loose Arms -- One-Piece Holders
If your toilet paper holder is a one-piece model, the arms can also loosen, but the cause is usually a loose screw or failed glue joint. To fix it, you need to remove the holder from the wall by removing the screws holding it and turn it over. You may find that tightening a single screw solves the problem, but sometimes you have to glue the arm as well. Remove the screw to separate the arm from the holder, then apply a small amount of carpenter's glue to the arm and the holder. Replace the arm and tighten the screw, then wait for six to eight hours before using the holder.
Repairing Broken Holders
If your toilet paper holder has cracked or split, take it off the wall and glue it back together. Use carpenter's glue to make repair to wood holders; after spreading the glue, clamp the pieces together with a C-clamp and wait for the glue to set. If the holder is porcelain or ceramic, use two-part epoxy glue. After mixing the two parts of the epoxy as directed, spread a little on both sides of the repair, push them together and use masking tape to hold them until the glue sets, which may take up to 24 hours, depending on the product. Wipe off any excess glues before it dries -- you can't easily do it afterwards.