Tubeless tire repair is necessary for tires on mountain bikes and some other vehicles. The process of fixing a tubeless tire is simple and similar to handling other tire repairs.
Find the Leak
First, you need to find the leak. This is not difficult as you will probably find sealant around the area if you've tried to seal it before. If not, you can spray a bottle of soapy water on the tire to see where it bubbles, indicating the location of the leak.
Plug Up the Leak
Slowly deflate the tire in order to pull it off the rim. This way, you can identify the leak in the tire from the other side. Fill or paint on sealant in the inside of the tire, helping to completely seal off the crack or puncture. Let the sealant dry completely or use a hair dryer to facilitate the process. Once the tire is dry, put it back on the rim and try to fill it with air. If the air stays in the tire, the tire is ready to be used.
A tubeless tire may not have as many parts inside, but it can still get punctures which need to be repaired.