[venk]

A few days ago I started getting this light when I pressed the brakes and so I assumed I neeed the pads and ordered the Porterfields. But after a day or so, the light has never come on again.

Questions:

1. Is the light supposed to come on and stay on when the pads wear out?

2. Was the above symptom just an electrical glitch or should I still go ahead in install the new pads? I have about 50k on it so it probably needs new pads anyway.

3. Would continuing to drive (and so using the brakes) after the light first comes on screw up the indicator in any way to make it stop indicating (not sure how the indicator actually works not having worked on these new fangled cars with electronic gizmos before!).

 

[slk230red]

venk,

1. When the brake pads wear down, the sensor comes in contact with the rotor, thereby supplying ground to complete the circuit to the brake pad wear down indicator lamp. At first, it may come on and off for a few miles until the pads wear a little more for the sensor to get a good seat against the rotor.

2. Go ahead and replace the brake pads along with new sensors. Usually, the lip on the rotor cuts into the sensor so I always replace the sensors when I replace the front pads.

3. You should have no problems driving the car and using the brakes for a short while, since the sensors are designed to make contact before the pads wear down to the metal. You'll just have to put up with the warning light staying on...but I would suggest you replace the pads now to prevent the caliper piston from coming out further as the old pads wear.

Good Luck,

Dave

 

[430]

Depending on the type of driving you do you have a decent amount of time before you have to replace the brake pads. Like everything else MB took the conservative approach here. That being said replace the pads when you get a chance. Brakes are not something you want to wait too long on.

When the brake pads were going in the ML I at first thought I was loosing fluid do to how low it was when I checked and the fact that when fluid was added the light went out for a couple of weeks.

 

[Bruce R.]

The sensors cost about $9.00 at the dealer .........

They're just a bit of wire with a plug on one end and a crimped on tube on the part that fits into a hole in the brake pad. You have a little time before you cause damage to either the disc or the caliper piston, but since the sensor is only on the inboard pad, you really don't know for sure.
The inboard pad should wear faster then the outboard because the piston works directly against the inboard.
Check out Periokid's site for a preview of what to do: http://www.slk32.com/pages/brakes/brakes.html

 

[venk]

Is there one or two sensors on the car?

Thanks for the info.

Confused from what a search turned up on the subject of sensors. Do both front wheels have sensors or just the passenger side on a SLK 230?

Also, do these OEM sensors fit the Porterfield pads?

It might be useful to post some definitive info on the above for future searches.

Thanks

 

[Bruce R.]

RE: Is there one or two sensors on the car?

It's been a long time since I changed the pads on my 230K, but I think there were two sensors. The Porterfield pads should have the holes in them, but if they don't, just get a drill bit that fits and put some in. It's no big deal, except the bit won't be worth much after drilling through sand, rubber, fiberglass, and all the rest of the crap they put in brake pads anymore.

 

[TXmudman]

I am glad to see this topic addressed today. I just had the same light come on this morning. It had me worried until I got the manual out and found out the cause. My car has 47,000 miles on it, and it's the first set of pads.

I only ordered pads for the front, assuming that the back probably don't have much wear. Do our cars use up the rear brakes as fast as the front? Should I have ordered both?

 

[Katika]

TXMudman, you should be fine. I have gone through a set of pads for the fronts and the rears are still going strong for now. That being said, my car has 60k plus miles and it is due for its brake fluid change too. I believe the front brakes take up the brunt of the braking hence the excessive brake dust (which is also due to the composition of MB OEM brake pads). I decided I will switch to Porterfields up front when this set of pads wear out, and continue using MB OEM for the rear.

 

[TXmudman]

Katika - 4/19/2005 4:01 PM

TXMudman, you should be fine. I have gone through a set of pads for the fronts and the rears are still going strong for now. That being said, my car has 60k plus miles and it is due for its brake fluid change too. I believe the front brakes take up the brunt of the braking hence the excessive brake dust (which is also due to the composition of MB OEM brake pads). I decided I will switch to Porterfields up front when this set of pads wear out, and continue using MB OEM for the rear.

Thanks for the info. I didn't know if all the ESP controls made the pads wear more evenly, or if the front wore out faster, as in most cars.

 

[robint]

Definitely two sensors - interestingly only £1.49 (about $3.50) each from UK MB main dealers rather than the $9 that Bruce R suggests for a US price. At last I've found something cheaper in the UK than the US!!!

Happy changing - its very straightforward.

 

[venk]

robint - 4/20/2005 6:35 AM

Definitely two sensors - interestingly only £1.49 (about $3.50) each from UK MB main dealers rather than the $9 that Bruce R suggests for a US price. At last I've found something cheaper in the UK than the US!!!

Never! But better than my experience in the UK. It should have been £3.71 in the UK given that most small things in the UK cost the same numeric equivalent as the US prices!

It was actually $3.71 each with tax in NJ and this dealer sells parts at list price. Either Bruce got taken or he in fact bought a pair for "around $9" and doesn't remember it (too much smoking gunpowder I guess) []

It should be a fun weekend. For some strange reason every PepBoy and Strauss discount auto store seems to be out of the required 7mm hex socket. Either very popular or very rare.