brakes

The caliper is not releasing. While it is still locked up, open the bleeder screw. If it still doesn't release, replace both front calipers. If it does release, something is blocking the brake fluid from returning to he master cylinder. You can narrow down the location of the restriction by cracking open the steel line in various places. If the brake releases when you open the line right at the master cylinder, suspect contaminated brake fluid. That will cause rubber seals to swell and grow past the return ports blocking them off.

When this only happens at one wheel, it's usually either the caliper of the flex brake hose causing the problem.