Most often the cause is a seized brake cylinder, especially on the nearside which is more subject to going through puddles. However, it does seem rather young for that to happen, unless it doesn’t get used regularly? It will be essential to release the auto brake adjuster first to get the drum off but I expect it will still be a bit of a struggle. If the cylinder is the culprit, the linings may also need to be deglazed and the drums checked for trueness. It would also be wise to inspect & repack the wheel bearing grease as well as it has suffered extreme heat.
