The victim of the attack was left needing an operation to repair broken bones in his face as well as the detached ear after the violence on Saturday.
The incident took place on Tat Bank Road, Oldbury, just before 10am on Saturday, as the victim was pulling into Kev's Tyres.
A 32-year-old man has since been arrested on suspicion of assault but has now been released while investigations continue.
A spokeswoman for West Midlands Police said: "We've arrested a 32-year-old man on suspicion of assault after he attended a police station yesterday afternoon.
"Following questioning he was released pending further enquiries as investigations continue."
In a Facebook post the victim's wife described the "devastating" injuries her husband had suffered.
She said: "He has had to have his ear stitched back on and has 30 fractures to his face and his jaw has been disconnected from his skull.
"His injuries are devastating and this beautiful man is in so much pain going through so much for no reason at all."