Some common repairs for a Mansfield toilet are changing a damaged valve, a damaged valve seal or a cracked flush valve float. You can easily do these repairs by yourself.
Usually, a Mansfield toilet leaks because the water level is set too high or the flush valve seal is damaged. To find out the part that needs to be repaired or adjusted, establish where the problem lies.
If your toilet only leaks or runs after it has been flushed, it may be that the water level is too high. Tighten the screw located at the opposite end of the float ball to lower the level.