Excessive Brake/Rotor Rust after 60K miles

[kbsilver]

Here's the deal. I was getting tired of the juddering and pulsation when coming to a stop. These were OEM rotors and Axxis Deluxe Plus pads (I know they are no longer sold). Although they had 4.5 years and 62K miles of service on the front, there was still 8mm of pad left. I just wanted smooth stops. They also saw 4 Northeast winters many of which had excessive use of road salt. Sometimes they put down way more salt than there is snow. I know how lots of towns can save money, but I digress.

Even with a lot of salt, the amount of corrosion seemed pretty extreme to me.

Look at the amount of rust:




Look at the raise lip of rust:



The end of the pad is worn away from the rust lip:




Proof these really are OEM Rotors:




Seems like much more surface pitting than I normally see in this amount of service. Bad batch of metal?




But the REALLY scary part, the pad fell apart when I took it off. The friction material separated from the backing plate. All I can see of the attachments are bumps of rust. The pad is flipped over, you are seeing the back side normally against the backing plate:



So is all of this normal? I don't want to think about what would have happened if that pad separated during some heavy braking.

All of the was replaced with Balo Rotors (made in Germany, apparently they have their own unique metal formulation) and Akebono Euro Pads. Figured the OEM rotors did not seem to hold up to the environment too well so I am giving the Balo's a shot.

[danewilson77]

Normal for 62k in nothing but salt. I recommend a coated rotor, and ceramic hybrid pads...

[kbsilver]

Normal for 62k in nothing but salt. I recommend a coated rotor, and ceramic hybrid pads...

A little late for this time around but will keep in mind for future brake work. The coated rotor makes sense but what are ceramic hybrid pads (brand name?). Lived in the NE all my life and never used a coated rotor before. Like I said is worse than I've seen before.

[danewilson77]

They are a ceramic/metallic hybrid, that will produce less dust (debris). stopping power will suffer as compared to a stop tech pad (or even an organic pad), but you prolly won't notice if you don't track your car.

[kbsilver]

They are a ceramic/metallic hybrid, that will produce less dust (debris). stopping power will suffer as compared to a stop tech pad (or even an organic pad), but you prolly won't notice if you don't track your car.

Sounds like the Akebono pads I installed (which are ceramic based) are what you have described. The have almost zero dust, and on our other car in 30K miles have not worn the rotor in the least, and acually has polished it to an almost mirror like surface. They have never squeaked, chattered, juddered or casued pulsating while stopping.

Thanks for the tips.

[jase007]

kb:

Don't think there is a lot you can do about that rust on the outside end of the rotor. Function of salt, moisture, exposure and you really can't protect it from the environment.

Can you put a brake micrometer gauge on it to see how thick the rotors are? I would suspect that 62k miles is the outer edge or service life on front pads and rotors in 4.5 years unless you are doing all highway miles.

I've had rotors rust up like that (and rear drums) when I lived in CT through the salted road winters. May just be a function of location.

I'd check your caliper pistons (if seals are broken) for pitting and rust which will lead to calipers sticking ... while you are "in there".

[kbsilver]

kb:

Don't think there is a lot you can do about that rust on the outside end of the rotor. Function of salt, moisture, exposure and you really can't protect it from the environment.

Can you put a brake micrometer gauge on it to see how thick the rotors are? I would suspect that 62k miles is the outer edge or service life on front pads and rotors in 4.5 years unless you are doing all highway miles.

I've had rotors rust up like that (and rear drums) when I lived in CT through the salted road winters. May just be a function of location.

I'd check your caliper pistons (if seals are broken) for pitting and rust which will lead to calipers sticking ... while you are "in there".

I did micro the rotors, they came up as 22.9mm with a limit of 20.4mm. There was almost no wear from the brake pads. I was going to save them for possible reuse after turning later, but the rust blistering was so bad going to toss them. The low dust pads seem to be VERY rotor friendly. Our 540 has been running Akebono pads on the front for 27K miles and there is no lip at all at the edge of the rotor. Still OEMs on the rear with a huge lip (32K miles and will need to be replaced in about another 7K, will switch to Akebono). The 540 is not a good test for rust comparison as is not driven in very bad winter weather, we only have snow tires for the 328.

As DW77 said, from now on I'll spend the extra $1-$2 and get coated rotors. As BMW does not sell coated rotors and I figured the coating would only be worn off by the brake pads anyway, I originally did not think anything of it. NOW I understand the value of protecting the non pad contact areas of the disc and will get coated rotors from now on (unless I move out of the NE).

Piston seals were in perfect condition and the piston compressed smoothly with no issues (I do change brake fluid regularly). I had no braking issues except for the annoying juddering and pulsating feeling.