What happens if you drive with damaged rotors?

We discovered that our 99 mercury Mountaineer had bad rotors.

last night I hooked up a trailer and was going to help a friend move a couch when I heard a loud grinding sound.

I turned around and determined it was comming from the wheel. I purchased a new set of pads and started to change the pads. In the process I found a broken sway bar connector. I changed this as well.

It still felt bad and there was a sound when I braked. I took it to pep boys for a free brake inspection. They pointed out that the rotors needed to be replaced.

I did not let them do it because I can not affor that right now. The car is a secondary not a daily driver.

My wife says we shouldn’t drive it at all. I say we can still drive it and expect I will have to replace the brake pads sooner than normal and replace the rotors when we can, later.

My wife insists we will do more damage if we drive it as it is. I say what’s the difference we need to replace the rotors anyway and I’m not worried about $20 brake pads I can replace myself.

If you install new brake pads on old rotors that don’t have the proper finish the brakes can make noise. And if the brake rotor finish is really messed up the noise will probably get worse and the brake pads will wear out quicker.

If this isn’t an everyday vehicle you’ll be good for now. But eventually the rotors will warp from poor friction material contact. When this happens replace both the brake pads and rotors.


So the for the sake of my wife who insists she knows better than me… driving with bad rotors results in a quicker wear time for brake pads and possibly more wear on rotors that already need to be replaced… other than that (generally speaking) nothing else is impacted?

I agree with Tester 100% and the answer to your latest question is yes. One point however…your braking system will be slightly degraded so avoid panic stops.

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Because of the poor friction material contact the brakes are going to run hotter. This is what causes the rotors to warp. It’s possible the brakes can get so hot where it damages the calipers. But when brakes get this hot you can usually smell it.

So other than that, the only things effected are the brake pads and rotors.


A lot depends on just how “bad” the rotors are…If they are really ripped up, badly scored, the new pads will QUICKLY wear out and your braking ability greatly reduced because of the over-heating and poor pad contact. Sometimes you can get away with minor scoring, but the pads will still wear quickly and it takes a while for the pads to “wear in” (to the uneven surface) and until that happens, braking is poor…Noise and rumble and squealing is to be expected…

What does “bad rotors” mean? Are they rusted? Are they worn below specs? Are they warped causing uneven braking?

The new pads will wear quicker on used rotors since the rotors are “grooved”. As long as you stop reasonably quickly you should be ok. If you have extemely long stopping distances and poor braking performance then you are due for new rotors.

After about 200 miles your new pads and old rotors should be mated up as best as they ever will. If you have decent braking performance at that point you should be ok until you need another new set of pads.

Thin rotors can warp easily. They also don’t transfer heat as well and that degrades stopping heavy loads, on hills, and in emergency panic stops. As it is, you car is less safe than it could be. It is hard to tell if you are unsafe to the point of dangerous.

Don’t drive the vehicle until it’s properly repaired. If you can’t afford new rotors, park it until you can.

On a side note speaking from experience the rotors and calipers can get so hot that they melt the carters key that holds your wheel actually on and while your driving down the road at whatever speed your tire can actually come off which is not good at all …trust me …

At the front a badly ground up rotor will quickly wipe the pads down to steel and after a few stops metal to metal the outer rotor surface will lose metal and the gap between the caliper end and the rotor will widen enough to allow the backing plate to drop out and result in immediate loss of brakes. Pumping might regain some braking action but it would likely also result in the caliper pistons being pushed out past the seals.

The worst case scenario is not pretty and from here in the dark I’ll assume you’re facing just that.

Ahhhh, caught me again. 2011. Musta gotten new rotors by now.

Well not wasted. Someone somewhere in the next ten years will do a search having not replaced the damaged rotors as his wife suggested. Then they’ll see your expertise. Bound to happen. Might take a few years but bound to happen.

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I hope to be around to enjoy someone noting their appreciation @bing. Could 80 be the new 60?

Driving a vehicle with a known safety issue and you get into an accident and someone gets injured or killed - you could be held criminally responsible (think jail time).