The ex-janitor who was expelled, became known as the "greatest repairman" with his exceptional skills - Requests from SSS rank parties and royalty don't stop coming is a Manga/Manhwa/Manhua in english language, Adventure series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Lyle has no combat skills, only his role as a "repairer". He is treated as incompetent in the party he belongs to, and the leader of the party banishes him from the party. Lyle is at his wit's end when a swordsman appears before him, asking him to repair an old sword...?