In Reply to: leaky rear tire posted by raski on April 23, 2022 at 03:52:04:
One thing to try is to get you a new valve stem cap, one that has a sealing surface on the top inside of the cap. This will seal the valve stem and stop the leak if it is leaking from the valve.
You can also replace the valve, but if it is very old you may not be able to get the old one out, or the whole valve assembly. I would try just the cap first. I did that years ago and it's still not leaking.
Below is a video on replacing the valve and the valve stem assembly.