CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

1971 Chevelle SS not parking on hill

So I got my 1971 Chevelle a few days ago, it has front disc brakes and rear drums, and I have been parking it on my driveway which is about a 30% incline and tonight while wiping the windshield the car started to roll back although it was in park with the emergency brake engaged. I have been hearing a clunking noise from the back when parking it in my driveway before but I didn’t think it was the brakes. Sometimes when parking it the car would roll a shortways back, about 1 foot and then it would stop and be fine. I thought I solved the problem by fully pressing the brake pedal in when putting it into park and engaging the emergency brake. Can you help me with it, I did move it also down to the street which is flat but I would like to put it back in the driveway for safe keeping

The “emergency” brake, parking brake really, operates the rear shoes through a cable. There are any number of things that can cause the brake to not set, but you think it is.

The cable can stretch so you pull on the brake handle but it doesn’t set the brake. The parking brake lever inside the brake drum is frozen on one or both sides and the cable is stretched. This combo even feels like the brake is being set properly, but its not.

The rear brakes shoes could be out of adjustment. again it will feel like it is being set, but you would also notice more pedal travel when using your brakes. The rear brake shoes could be frozen and again, it would feel like your parking brake is being set and even your regular brakes would feel normal. Since the front brakes do the majority of the stopping in traffic, you might not realize the rears aren’t working.

Either you or your mechanic are going to have to get the rear end off the ground and pull the brake drums off and inspect the brakes and the brake cable.

Last thing, even in their best day, parking brakes seldom held on a 30° incline. That was a benchmark test that a lot of new cars would fail.

The other issue appears to be that the parking pawl in the transmission is “gone”. That rolling back before stopping and noise was probably due to the pawl on the way to a permanent dirt nap. The pawl alone should be able to hold the car from rolling with the exception of very steep inclines. If the prior owner relied only on the pawl in circumstances similar to yours, then that would explain why it’s toasted now. That needs to be fixed. You shouldn’t rely on the parking brake to be the sole method of holding the car.

With that steep an incline, you should probably chock the wheels, too. It was a good thing you were near your car when it started to roll back, and not inside when it let go.