A cop involved in the fatal shooting of Sean Bell on his wedding day is now suing the dead man's estate -- claiming Bell drunkenly assaulted and badly injured him with a car right before the hail of police gunfire that brought the unarmed man down.

Police Officer Michael Carey's lawsuit says Bell was boozed-up when he got behind the wheel of the car after his bachelor party on Nov. 25, 2006, and also claims the doomed groom failed to wear glasses or contact lenses despite having poor eyesight.

Carey's allegations are contained in a Brooklyn federal counter-claim filed last week in response to a wrongful-death lawsuit being pursued by Bell's fiancée, Nicole Paultre Bell, against him and the other four cops involved.

SEAN BELL Slain on wedding day.

"[Officer Carey] suffered serious leg injury when [Bell] crashed into the vehicle he was riding in before Officer Carey ever drew his gun and fired a shot," said Carey's lawyer, Richard Signorelli.

Bell, 23, and his entourage were shot at 50 times by five officers, including Carey, after they left a strip joint, Club Kalua, in Jamaica, Queens.