Pat McGlynn, 52, was waiting at traffic lights about 200 yards from his home in Liberton, Edinburgh, when he noticed a man approach his window.
Mr McGlynn said he rolled down the window to see what the man wanted but was immediately punched on the face and head.
He said: "It came out of no-where.
"He kept hitting me but I am still quite weak after the heart attack. Normally I would have tried to fight him off but I just couldn't.
"It was really awful - he kept shouting about the Bay City Rollers all being paedophiles and perverts and p******s, but none of that has ever had anything to do with me.
"I think he was in his 30s, he was very stocky and had a skinhead, I think he was on drugs or something because everything he was shouting was slurred."
Mr McGlynn suffered a heart attack on 3 October, and was on his way back from a check-up at the Royal Infirmary of Edinburgh when the assault happened at around noon on Saturday, 23 October.
He managed to roll the window back up and drive off, leaving his attacker behind. The guitarist's ordeal was witnessed by two women who were behind him at the traffic lights.
Mr McGlynn added: "When I got home I was in shock, I never even told my wife Janine what had happened, I just slumped on the couch trying to catch my breath.
"Then these two women came to the door to say they had seen what had happened and that they had called the police.
"I don't even know who they were, but I'm glad they contacted the police - I was in too much shock to think about that."
Mr McGlynn said the attack had left him with a cracked collarbone and two of his teeth had come loose.
A police spokesperson said: "Lothian and Borders Police are investigating a report of an assault on a 52-year-old man in Liberton Brae at midday on Saturday 23 October.
"We are appealing for anyone who was in the area at the time, and who may have seen what happened, to get in touch."
Mr McGlynn, who joined the Bay City Rollers in 1976 but left after seven months, is at the heart of a royalty's payment battle with former band mates and record label Arista.
He said he is now seriously considering moving away from Edinburgh to a location where he will be less recognisable.
He said: "I find that the type of people who recognise me here are the wrong ones - not fans anyway - just troublemakers.
"This is just the latest in a strong of verbal and physical abuse I've had to face, just for being in a band.
"I spent a few months in Cambodia with my wife recently, and it was so chilled out there, hardly anyone knew who I was. I'm thinking about just upping sticks to there, for a quieter life."