Replace the longer Mansfield toilet handle
Turn off the water supply to the toilet.
Flush the toilet.
Flush again and hold the flush handle down to allow as much water to leave the tank as possible.
Unscrew the nut holding the toilet lever to the tank by the opposite direction to remove it – i.e. clockwise.
Slide the nut off the arm of the lever and maneuver the old lever out of the tank.
You may have to yank the fill tube off the flush valve top; pull straight off the disk.
Unscrew the disk from the flush valve top.
Remove the flush valve float off the flush valve by lifting the float out and turning it to slide out the flush handle stem from the slot.
Place the new lever into the tank and slide it through the flush valve slot.
Screw the nut holding the toilet lever to the tank by the opposite direction to attach it – i.e. counter-clockwise.
A flapper-flush design needs the flapper chain reattached.
Replace seal gasket
When your toilet is topping off often, that’s a sign the flush valve seal is worn out. A Mansfield flush valve does not use a flapper and chain. It has a tower float that lifts as the toilet flushes. On a Mansfield flush valve, you can replace the seal without removing the tank.
Turn off the toilet water supply to the tank. Lift the toilet tank lid off of the toilet and set the lid on a flat surface. Flush the toilet, and hold the flush handle down to allow as much water to leave the tank as possible.
Yank the fill tube off the flush valve top; pull straight off the disk.
Unscrew the disk from the flush valve top.
Remove the flush valve float off the flush valve by lifting the float out and turning it to slide out the flush handle stem from the slot.
Pull the old red rubber flush valve seal out of the flush valve. It is at the bottom of the flush valve. The seal fits in a groove and will pull out with your fingers.
The replacement flush valve seal goes over the flush valve bottom in one side of the seal the groove, the follow the rest of the seal into the groove with your fingers.
Wipe the bottom of the flush valve float with a rag. Put float back on the flush valve with the flush handle back into its slot.
Screw the disk back on the assembly and stick the fill tube back.
Turn on the water.
Turn off the water supply to the toilet.
Flush the toilet.
Flush again and hold the flush handle down to allow as much water to leave the tank as possible.