Funny Brakes... Is it this wear line any indication?

[azitizz]

Ive found my brakes are braking a little lightly once in a while. Its inconsistent but noticeable when it happens.

Its not that the car wont stop, its just as if pressing on the pedal with the same force as usual , I will give the impression of not grabbing as hard once in a while.

I was wondering if the wear lines on my front rotors, which were just replaced, along with new pads and new/rebuilt callipers, is any indication of something wrong. You can see the outer rings of the rotors are not wearing smoothly.

Is this kind of inconsistent wear normal? I'm a little surprised at how its wearing when the whole kit was replaced at once. The rotors became very rusted after one winter of driving... I Imagine that's normal, where the roads are salted like here. But is it avoidable?

[t walgamuth]

If you are getting less results erratically I would look at the booster and the vac lines that feed it, then the vac pump.

I was not able to get the pictures to open earlier. That outer portion looks recessed to me. Not normal but I don't see how you can get it from the brake pads.

[tangofox007]

Originally Posted by azitizz

Is this kind of inconsistent wear normal?

Is the rough area in the pictures the outer portion of the rotor contact surface or is the edge (outer circumference) of the rotor? (Those are great pictures, but my eyesight just isn't what it used to be.)

If it's the former, it most definitely is not normal. The pads should be making even contact to within about 1/8" of the outer portion of the rotor face.

[tjts1]

That brake rotor is toast and the braking ability is greatly reduced vs a new rotor.

[toomany MBZ]

Normal.

Pull the wheel and have a closer look.

The outer most edge doesn't have pad contact, wear lines, again, normal.

It is prudent to install new rubber lines when you do the described replacement.

What is the condition of your M/C?

[vstech]

NOT normal!!!

I've got hundreds of these cars, and NONE of them have that large a non contact area.
something is amiss in the pad/caliper area...

[toomany MBZ]

All five of my MBs have been flawed, seemingly.

[t walgamuth]

I was not able to get the pictures to open earlier. That outer portion looks recessed to me. Not normal but I don't see how you can get it from the brake pads.

I'd pull the wheel so I could see the rotor better. Please do that and post pictures of it so we can see the edge. I'd also measure it and see if its thick enough.

[vstech]

Originally Posted by toomany MBZ

All five of my MBs have been flawed, seemingly.

I doubt it. more likely you are not seeing what I am seeing in the pictures he's posted.

there is a QUARTER INCH OF UN TOUCHED ROTOR AREA AROUND THE EDGE

that's not normal.

most have at most 1/16" lip at the very edge of the rotor.

[vstech]

Originally Posted by t walgamuth

I was not able to get the pictures to open earlier. That outer portion looks recessed to me. Not normal but I don't see how you can get it from the brake pads.

I'd pull the wheel so I could see the rotor better. Please do that and post pictures of it so we can see the edge. I'd also measure it and see if its thick enough.

it looks like he has pads that are MUCH smaller than the face of the rotor. I bet his pads are incorrect for the car.


OP: please pull the wheel, and the caliper and post pics of it all...

[nelbur]

I think what looks like an unworn part of the disc, is actually something behind the disk. It does look strange, but I think the disc is worn normally.

[toomany MBZ]

Originally Posted by vstech

I doubt it. more likely you are not seeing what I am seeing in the pictures he's posted.

there is a QUARTER INCH OF UN TOUCHED ROTOR AREA AROUND THE EDGE

that's not normal.

most have at most 1/16" lip at the very edge of the rotor.

Okay, at least one of the attachments has been enlarged.

[tjts1]

No, this is a damaged rotor and pad. I wouldn't drive with brakes like this.

Originally Posted by azitizz

This isn't. This is perfectly normal wear.

Originally Posted by toomany MBZ

[t walgamuth]

The second picture looks very normal but it does not resemble the one above.

[97 SL320]

According to the thread below, the rust will just wipe off after a few days of normal driving. ( It won't. ) Rust has reduced the proper rotor area to 25%.

Rust Spots Rear Rotors: Necessarily Indicative of a Problem?


I've seen worse, in the current thread. Top pic in post 13 shows a growing ring of rust that has become burnished by the pads. While not a major disaster to drive on, I'd get some use out of the pads / rotors and change both at the next service. Be sure to repack wheel bearings too.