How to Repair a Leaking Pressure-Assisted Toilet

Fixing a Pressure-Assisted Toilet

Pressure assisted toilet
Aaron Stickley

A pressure-assisted toilet that continues to run after the flush often does this 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.

This is a flushmate-style (power flush) toilet, so it takes 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 top part of the bolts. This may require you to remove the pressure tank from inside the toilet tank.

Tools and Materials You Will Need

  • Socket wrench with deep sockets (or an adjustable wrench)
  • Mini hacksaw (if needed)
  • A new set of tank bolts and gasket

Empty the Tank

Empty pressure toilet tank
Aaron Stickley
  1. Shut off the water by closing the shut-off valve attached to the bottom of the water inlet valve.
  2. Empty the toilet tank by flushing. This will remove the pressure from the pressure tank inside the toilet tank.
  3. Remove 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.   
  4. 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. 

Remove the Tank Bolts

Cutting toilet bolts
Aaron Stickley
  1. Find the toilet bolts that are located where the toilet tank and the bowl meet, located below the tank and behind the toilet bowl. You should be able to get at them from outside the tank with a deep socket or wrenches.
  2. If the bolts will not come off easily, you may have to cut the bolts. With a skinny hacksaw blade or narrow 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.
  3. 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.
  4. Lift off the toilet tank and set it down to continue. 
  5. Take the bolts out, and clean the area between the tank and the bowl before installing the new bolts.

Install New Tank Bolts

Replacing toilet tank bolts
Aaron Stickley

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 off the tailpiece of the pressure tank where it extends through the bottom of the toilet tank. The pressure tank unit should now easily pull out of the tank. 

  1. Put a rubber washer on each of the new tank bolts, then slide the bolts through the mounting holes from inside the tank.
  2. On the bottom of the tank exterior, install another rubber washer onto each bolt, then thread nuts onto them. Tighten up the nuts so they are snug and slightly squeeze the rubber washers. Do not overtighten; it is possible to crack the porcelain of the tank. 

Over-tightening can cause the tank to crack, so tighten the nuts a little at a time.

Reinsert the pressure tank if you had to remove it to gain access to the tank bolts. 

Replace the Gasket

Tank to bowl gasket
Aaron Stickley
  1. Remove the large gasket attached to the bottom tailpiece on the pressure tank. On power flush toilets, the gasket is larger than the normal tank-to-bowl gasket. Remove the old gasket by just pulling it off.
  2. Push the new gasket into position around the tailpiece of the pressure tank. It should fit completely around the plastic mounting nut.  
  3. Reset the tank onto the toilet bowl, inserting the tank bolts down through the holes in the rear platform on the toilet bowl. Thread washers and nuts onto the tank bolts, and tighten them down evenly until the tank is secure and does not wobble. The new gasket should slightly compress as you tighten. 

Check for Leaks

  1. Reattach the water supply tube to the tailpiece of the water inlet valve extending out the bottom of the toilet tank. Turn on the water shut-off valve and inspect for leaks at the connection. 
  2. 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 better.