Changing a Belanger shower faucet cartridge solves the problem of water leaks and low flow rates in the faucet. The cartridge, which is the faucet's main valve system, contains two inlets for hot and cold water. Each has a rubber seal, and when worn out, it causes a leak. If the inlets in the cartridge clog with sediment, the faucet flow rate is affected. Both problems are corrected by swapping out the old cartridge for a new one. The process does not require a plumber and takes less than half an hour to complete.
Shut the water pipe valves inside the shower wall, which are usually accessible through a panel in the wall. Or turn off the home's main water supply valve, if there is no access to the shower wall.
Remove the Belanger shower handle by taking out the screw underneath the handle with your Allen wrench. Slide the handle off after you have removed the screw.
Unscrew the two trim screws in the faucet trim, the round part around the base of the shower, and take this part off.
Loosen and remove the dome cap by turning it to the left and then unscrew the cartridge cover with a large wrench or channel pliers.
Take the cartridge out and insert a new one, making sure the seals in the cartridge line up with the holes in the faucet. Replace the cover, dome cap and trim. Then replace the handle and tighten its screw.