DDArchitect

Hi All,
I bought this car in 2019 and made a trip across Canada and then certified my vehicle in Ontario which meant I had to replace my Rear brakes and rotors (They installed cross drilled Zimmermann rotors). Over the span of 4 years only the left rear rotor has developed deep grooves. There was no noticeable warning at all. At slow speeds in City driving as i slow down It appears that maybe the caliper is delayed in it's release.

• Is the caliper the likely culprit?
• Does anyone know if I should be looking at replacing the caliper, brakes and rotors together to correct this?
• How long should an average mechanic take to complete a job like this? And what should I expect to pay here in Canada?
• Are cross drilled rear rotors recommended since its a rear wheel drive?

Thanks in advance for any helpful responses!

112233

Hi,
do you have an infrared thermometer? If yes, drive some km in the city and measure the temperature of the brake rotors. Is the temp left/right different 10 deg or more, it is likely that you have a seized caliper.
In general, cross drilled rotors all get grooves which is no problem. With a 2007 car, cross drilled rotors are just for show and do not have any additional usage. The early w203 had horrible breaking in heavy rain, there could have been a benefit from crossed drilled rotors. Later models had a wet-breake option in the ESP module integrated.

slammer111

The caliper may require some remanufacturing. To be honest, a wrecker may be more cost efficient.

Can't comment on the cost. Wrecker will be cheapest. Labour is what kills everything in Canada.

Not sure if the rear discs were ever cross drilled on the W203. The rear discs are much smaller than the front discs. I have no idea why there would ever be a need to cross drill them. Just stick to the stock configuration, should have no cross drilling. Cross drilling is only for looks for pretty much every street car.

DDArchitect

Thanks 112233,
I'll see if I can get a hold of an infrared thermometer and try that out, now that the cold is here that should work really well. I remember questioning the rotors being drilled in the first place but I know that the previous owner was a fanatic about the car (good in my case) because the car was in great shape, I imagine he upgraded to drilled for the looks but then again I wasn't sure what it would have had for stock rotors since it's a C230 Sport.
Thanks for the advice I'll try it out, but have a feeling you're right about the caliper. I'll post my findings.

ErnieKessler

Consider replacing both rear calipers, brakes, and rotors to address the deep grooves on the left rear rotor. Inspection by a trusted mechanic will determine if caliper issues contribute. Costs and time can vary.