How to Repair Leaky Toilet Tank Bolts

Looking down at an open toilet tank.
  • 1-2 hours
  • Beginner
  • 10-50
What You'll Need
Adjustable wrench
Towels and sponges
Blanket padding for the tank and lid
Flathead screwdriver
3-in-1 or WD-40 lubricant
New rubber washers
New bolt nuts

After thousands of flushes, the toilet tank bolts may begin to leak as the rubber washers inside and outside the tank wear out. Drips of water on the bolts and nuts, and on the floor under them, will show when it's time to make the switch. Do this as soon as possible, as the added moisture can rust and corrode the bolts themselves as well. Follow these directions to replace the worn out rubber washers and get your toilet tank back into tip-top shape.

Step 1 - Drain the Water From the Toilet Tank

Shut off the water flow to the tank at the water shutoff valve, and flush the toilet to empty it completely. With the adjustable wrench, pull the water supply line clear of the toilet tank. Absorb any overflow by laying with towels and sponges behind the toilet bowl.

Step 2 - Remove the Tank Lid

Lift off the toilet tank lid and set it aside on a large pile of blankets and towels, leaving room for the tank as well.

Step 3 - Remove the Tank Bolts

With the adjustable wrench, try to loosen the nuts from the bolts. If they are stuck, hold the nut with the wrench while a helper turns the bolts with the screwdriver from inside the tank. Apply some penetrating oil such as WD-40 or 3-in-1 if the bolts still prove stubborn. Keep turning the nuts until you can pull them out completely

Step 4 - Lift off the Tank and Set it on Padding

With a helper, lift the tank straight up and carry it to the padding, laying it down flat for safety.

Step 5 - Remove and Replace all the old Rubber Washers

You can now extract the bolts from the tank, removing all the old rubber washers. Discard these and slide the new ones in their place. Put one rubber washer on the bolt so that it sits between the tank and the bolt head. Insert this into the tank hole, and then put a second rubber washer on the bolt on the outside of the tank. Attach a new nut before finishing up with a third rubber washer. Add a new metal washer to secure the tank to the toilet bowl housing. Then, replace the washers and nut on the second bolt in the same order.

Step 6 - Reattach the Tank and Refill

You and your helper can now raise the toilet tank back over the toilet bowl housing and reseat the bolts and central tank gasket correctly. Fasten the bolts alternately with a few turns at a time of the adjustable wrench. Check that the toilet tank is connected solidly and is staying perpendicular to the bowl housing. Finally, reconnect the water supply and refill the toilet tank, setting the lid back into place last.

Step 7 - Check the Bolts and Washers

Over the next 36 to 48 hours, check the toilet tank bolts for any recurring leaks. If they leak, you will need to replace the bolts, nuts, and washers again. If not, your replacement has been successful, and you can rest easy.