Darkmann

Yep, after finding out two weeks ago that the rears don't have a wear sensor, just yesterday the wear sensor light came up on the dash - meaning the front ads are nearing their end of life. For moderate city driving, how much pad do I have when this light shows up? I have another 3K before next service and I'd rather wait and do it then. Soemhow, I doubt that the pads will last 3K. What's your best guess average?

fritza2tt

Pull the wheels off and visually inspect the pads. The original pads are beveled on the side so you can slide your finger nail under the edge of the pad. If you can, then there is still plenty of pad remaining. However, the important thing is to make sure that both pads, inside and outside are wearing evenly. If they do, that tells you that the brake caliper is floating and functioning normally and that there should not be an immediate problem developing. I do this check every time I rotate the tires, about every 6,000 miles. I now have over 66,000 miles on the brakes (and tires) and hope to make it to 100,000 miles before replacing the pads, not the tires. In your case I would ask myself, how many miles ago were the brake pads installed. If this was 30,000 miles ago, then 3,000 miles more would mean an additional 10% of wear.

bigtire

When my brake sensor indicated brake pad wear I went another 1k and when I replaced the pads I had to relace the sensors as well. The sensors are imbedded in the pads and if you replace the pads right away you can reuse the sensors. If you put the brake job off the rotor starts to cut into the sensors. All this happens long before the pads completely wear out (read metal on metal grinding noise)

fritza2tt

Good post, bigtire. But pray tell, whatever did we do before we had sensors? My suggestion would be, if it's a new car or if the old girl is going to drive your car, then better make sure that you replace the pads before the sensors get ruined.

fritza2tt

Darkmann, if you have original brake pads, they should be beveled so you can push your fingernail in between the pad and the rotor. I think as long as you can do this, there is plenty of brake pad remaining for another 3,000 miles - so I would guess. I just ran into the same problem, brake pad wear light cam on, I pulled off the wheels and saw where the pads were still beveled. I put the wheels back on and ordered a set of new front brake pads. Now I have to figure out how to do the replacing - myself! The pads where a little over $40, I'm not going to have the rotors turned and I do not foresee any problems, unless somebody can tell me what to look out for. By the way, I have over 75,000 miles on the car, original brakes and original tires - and I just turned 75 myself. Maybe that will help to explain it. :-)

MARK CUMMINS

Here is Some Info RE front pad replacement
http://www.mercedesshop.com/e_class_brakejob.htm

scorchie

If you are relying on the brake sensors, you can wait until your brake replacement warning light GOES OFF before you replace the pads.

(Seriously... there is brake pad material UNDER the sensor... but if you are negligent in replacing your rotors the lip on the rotor might touch the pad. No big deal really.)

-s-

fritza2tt

Thanks, all. Really, once you do one side, you realize how well engineered this car is. The only additional tool I had to get was the 7 mm Alan wrench. Observations: the lip on the outside edge of the rotor touches the sensor way too early and that sets off the warning light. Now I am tempted to disconnect the warning sensor and just observe the pads when I rotate the tires. When they get down to one eighth of an inch, it is time to look for brake pad replacements. Part of brake pad replacement should also be a change of brake fluid. But, rather than forcing the fluid back into the master cylinder reservoir, would it not make more sense to open the brake bleed valve and allowing the fluid to escape? Then drawing out, perhaps with a sysinge, the remaining brake fluid from the reservoir, replacing it with fresh fluid before bleeding the brakes thoroughly afterwards?

scorchie

Some cars do not have the brake sensors ... it seems to vary from year to year and on models. For instance, my CLK55 has no sensors on the rear. I helped my friend with his 1995 C36 today and it had one sensor on the outside pad of the left rear, none on the right rear, and one on each front pad (total five on the car).

I prefer to flush the brakes every two years or less, using either a MityVac or a pressure bleeder. I find that bleeding with the master cylinder can cause premature failure of the master cylinder.

I generally alternate ATE blue and gold fluids so that I can see when the system has been completely flushed (the color of the fluid changes at the bleeder valves).

-s-

E-Klasse

My 96 E-Class has the additional sensor on the outside pad of the left rear and none on the right rear as scorchie mentioned.