Carsy

I checked my brake pad wear during my B Service (22,500km) & calculated how long the pads would last at the current wear rate.

Front Pads:- .6 mm wear in 22,500 km = 336,000km

Rear Pads :- 1.45mm wear in 22,500 km = 136,500 km.

It is strange to me that the rear pads are wearing at nearly 2.4 times faster than the front pads.

I drive in a reserved manner in country conditions & do no leave the hand brake on

I find it unusual that after only 2 mm wear on the front discs & 1.7 mm on the rears that the discs have to be replaced. (Specifications from Haynes w203 book)

Glyn M Ruck

John.

There could be a number of issues at work here.

1) Your service cycle might just result in this wear ratio. In-town operation accelerates front wear. We see this with tyres. In-town cars especially with staggered set up seem to wear front & rear fairly evenly whereas open road cars seem to chew up rears more quickly - this is once again very service & driver dependant.
2) You should continue to monitor. The wear pattern might change now that the discs have run in. Surface finish on new discs could have accelerated rear wear. Maybe the surface finish of the new rear discs was rough compared with the front. If this was the case rear wear will slow.
3) Benz had a bad batch of rear pads out there that they replaced on some cars under warranty. Does your car dust it's back wheels badly? It should not. If it does you likely have the bad pads. Make the dealer replace them.
4) Benz is very conservative on disc wear. You should get a good 100,000 Km or more out of a set of discs.

I would not loose any sleep about it - just monitor.

AMGTTV8

Yup - got the same problem...

Have an 09 and the rear brakes are always more dusty than the front, even when I track the car....

My tech said they must have carried the ****ty pads from the 08 to the 09...

Unfortunately they wont replace them ....BOO

Carsy

No, the rear pads do not dust the wheels badly so the pads must be OK.

Interesting though, that country cars wear rear brakes & rear tyres much faster than the fronts.

Discs have become much softer over the years. My 1979 Pug still had the original discs after 450,000 km & the 1994 Pug did 200,000km on the front discs. I am hoping for more than 100,000km on the W 204!!! I may buy a micrometer to monitor them closely!!
Thank you Glyn.

Glyn M Ruck

Ever since asbestos was chucked out of brake pads - friction materials & disc metallurgy have changed considerably.

C230Ak

I think I know the answer but thought I'd ask anyway. On my 209 CLK, after a normal driving cycle, my rear brakes are noticeable hotter than the fronts. I can hold my hand on the front disks just fine but on the rears it burns after just a second touching them. I assume that this is as a result of the smaller, solid disks. That being said, does anyone know of a modification, such as a CLK AMG rear brake swap that would give me ventilated rear disks?

Thanks!

Adi-Benz

Idk about the CLK, wrong section, but our front rotors are drilled so less heat, whereas the rears aren't. Probably similar case for you as well.

C230Ak

Yeah, C and CLK tend to be very similar in their underpinnings from what I've seen/read. Figured if there were any levels of C class that had vented rears there'd be hope for a CLK. I'll look in the 209 specific threads as well. My fronts are not drilled or slotted but have ventilation inside the disk whereas the rears are a solid ring of steel.

Adi-Benz

I would think aftermarket ones should fix the issue though. Might as well do them all haha.

Funkwagen

I don't think drilled rotors are going to help with anything, it's really down to how the car handles the brake balancing with electronic brakeforce distribution. Most peoples driving style will put more emphasis on the rear brakes than the front for the most part with gentle stopping.

C230Ak

I don't mean cross drilled, I mean vented, like with the vanes sandwiched between the rotor surface that pull air through the disk.

Wait, you're telling me these cars have electronically controlled front/rear brake balance control! And that when I drive as gentle as possible it may only be using the rear brakes? That would explain why the rears are always super hot, ha! But then having ventilated rear rotors would be even more beneficial if they're doing the lions share of the work.

Carsy

If you are not pushing the limits or on a race track, why worry ?

When driving sedately maybe the rears are used more but in an emergency stop most i.e. 80% of braking is done by the front ventilated rotors.

I would check whether the rears are "dragging" i.e.the handbrake is not completely off.
How does the car roll when stationary on a flat area ? Try by pushing it yourself. It should not require much effort if all is OK.

C230Ak

One time, only once, I got out of the car and could smell brakes. Rear driver side was spit sizzlin'. Thought I was gonna be buying new calipers. I removed the pads and and cleaned the retaining pins of both rear calipers and reassembled with some anti-seize. Hasn't happened again in the months since. Car rolls down the slightest incline in neutral. I stopped applying the parking brake so if it is sticking the shoes should wear away eventually, lol. Ever since then I check them everyday. I guess it's just my OCD that says the fronts should be hotter, heh.

I have taken it to a performance driving day at Brainerd international once. Would do it all the time if I wasn't broke! XD

Adi-Benz

Drilled as in holes, not slotted.

Funkwagen

Ah, I misread that. Yeah, the car will adjust the brake balancing with the ABS/ESP unit to provide optimal/smooth braking, which is why people tend to see the rear brakes wear a bit faster than the front. I don't think the rear brakes need changing to vented, but what they do need is some occasional maintenance.

Here in salty, rusty Ontario, the rear calipers tend to build up a lot of road grim and corrosion over the winter, and the pads can kind of seize up in their brackets. They don't move as freely in their brackets, and sometimes end up rubbing against the rotor while no brake pressure is applied. It builds up extra heat (and possibly dust?) and can also result in accelerated brake wear if it gets very bad. I noticed this when doing the rear brakes on my mothers C300, they were very stiff and had TONS of grime/corrosion buildup - I spent a good 30 minutes sanding down all of the junk caked onto the pad carriers in order to get the new pads moving smoothly. The actual condition of the pistons in the rear calipers were just fine though, they moved as smoothly as they should.

I disassemble the rear brakes and clean them up/reapply some lube before the winter to keep it from happening, it's helped a lot. The front brakes don't seem to have this problem as much, possibly because the front brakes don't see quite as much grime as the back ones.

thesaintusa

Depending on the roads you are driving on and your driving style the rears may wear faster if you are engaging the traction control in a RWD vehicle.

In regions with snow, Jeep Wranglers in particular seem to go through rear brake pads quite quickly as the traction control is being engaged often as the speed of the wheels is being constantly regulated.

I just shut off the traction control and keep the ECS on.

Just a thought.

C230Ak

Oh yeah! I thought I was going to have to replace the caliper cause I couldn't remove the pin. I went through a number of punches and a can of WD40 before it gave. TBH I'd like to upgrade the fronts AND rear brakes tot the CLK550 hardware but I already have a set of cryo treated front rotors. If I do a rear swap it'd be just for fun I think.

It was very enlightening to find out why my rears always feel like they were working harder than the fronts though (and I do love getting the rear lose on slick roads! ;P )