Not sure how I did not notice it, but I drove for about 12 miles at 55 with the parking brake on. What's the damage. What do I need to fix. Brakes are EXTREMELY sluggish now and I have to pump to stop.

I know - I am an idiot.

97 SL1 240K

 

So open up the rear drums and have a look. If the shoes are not worn to nothing and the drums are not turning blue or ground up then adjust your rear shoes and go on your way. You didn't mention the year, so you could have rear disc brakes.