How to Repair a Leaking Pressure-Assisted Toilet

Pressure assisted toilet
Aaron Stickley
Overview
  • Total Time: 45 mins
  • Skill Level: Beginner
  • Estimated Cost: $10

A pressure-assisted toilet that continues to run after the flush often does so for the same reason that a standard gravity toilet does it. When you have a leak between the tank and the bowl of a toilet, it is because of problems either with the bolts holding the tank to the bowl or with the gasket that fits between the tank and the bowl.

Since the parts are different, repairing this problem in a pressure-assisted toilet is just a little different than for a gravity toilet. Even though the tank interior of a pressure-assisted toilet looks completely different, don’t let that discourage you from making repairs.

The toilet shown here is a Flushmate-style (power flush) toilet, which requires a special gasket. Also, the old tank bolts can be a little more difficult to replace than on other toilets because the large pressure tank inside of the toilet tank blocks the tops of the bolts. With this and similar systems, you have to remove the pressure tank from inside the toilet tank to access the tank bolts

What You'll Need

Equipment / Tools

  • Tongue-and-groove pliers
  • Socket wrench or adjustable wrench
  • Mini hacksaw (as needed)

Materials

  • Tanks bolts and washers
  • Pressure tank gasket (optional)

Instructions

  1. Empty the Tank

    Shut off the water by closing the shutoff valve on the water supply line under the toilet. Empty the toilet tank by flushing. This will remove the pressure from the pressure tank inside the toilet tank.

    Disconnect the water line that extends into the pressure tank from the water inlet valve. Flush a couple more times to help drain the pressure tank of any residual water.  

    From outside the toilet tank, disconnect the water supply tube that is attached to the tailpiece of the water inlet valve, located usually on the bottom left side of the toilet tank. You may need channel-type pliers to loosen the fitting on the supply tube.

    Empty pressure toilet tank
    Aaron Stickley
  2. Remove the Tank Bolts

    Find the toilet bolts that secure the toilet tank to the bowl, located below the tank and behind the bowl. You may be able to get at them from outside the tank with a socket wrench and a deep socket or with an adjustable wrench.

    If the bolts will not come off easily, you may have to cut the bolts. With a skinny hacksaw blade or other thin cutting tool, cut the bolts off in the narrow space between the toilet tank and the toilet bowl. Since you will be installing new toilet bolts, it is not a problem to ruin the old bolts.

    There may be another set of nuts and washers holding the bolts onto the tank. Either unscrew the nuts and remove the bolts or cut away the rusted nuts to remove them. Once again, a skinny blade can be wedged between the tank and the nut to cut it out.

    Lift off the toilet tank and set it down. Take the bolts out, and clean the area between the tank and the bowl in preparation for installing the new bolts.

    Cutting toilet bolts
    Aaron Stickley
  3. Install the New Tank Bolts

    You may need to remove the pressure tank from the inside of the toilet tank in order to put in the new tank bolts. To do this, unscrew the large plastic mounting nut from the tailpiece of the pressure tank where it extends through the bottom of the toilet tank. The pressure tank unit should easily pull out of the tank. 

    Put a rubber washer on each of the new tank bolts, then slide the bolts through the mounting holes from inside the tank.

    On the bottom of the tank exterior, install another rubber washer onto each bolt, then thread nuts onto them. Tighten up the nuts, a little bit at a time, so they are snug and slightly squeeze the rubber washers. Do not overtighten; it is possible to crack the porcelain of the tank. 

    Replacing toilet tank bolts
    Aaron Stickley
  4. Replace the Gasket (optional)

    If your toilet seems be leaking at the tank-to-bowl joint, replace the gasket on the tailpiece of the pressure tank. Remove the old gasket by just pulling it off. Push the new gasket into position around the tailpiece. It should fit completely around the plastic mounting nut. 

    Tank to bowl gasket
    Aaron Stickley
  5. Reinstall the Tank

    Reset the tank onto the toilet bowl, inserting the tank bolts down through the holes in the rear platform on the toilet bowl. Thread the washers and nuts onto the tank bolts, and tighten them down evenly until the tank is secure and does not wobble. The pressure tank gasket should slightly compress as you tighten. 

  6. Check for Leaks

    Reattach the water supply tube to the tailpiece of the water inlet valve extending out the bottom of the toilet tank, and tighten it gently with pliers. Turn on the water shutoff valve and inspect for leaks at the connection. 

    Fill the tank back up and flush it a number of times to make sure there are no more leaks. Also, if your tank is a still a little loose, the extra weight from the water in the tank will help you tighten the tank a bit more.