dra5697

I am going to change the brakes on my E320 this weekend and I was wondering if anyone had any pointers... especially with the electronic break sensors. I am not sure if they are even connected now cause the lights or warnings they are supposed to trigger never even went off. The only way I knew is I got a flat and had to have the tire changed and the guys at the shop told me they needed to be changed... what does the sensor do anyway?

Oh well any pointers or anything special I need to know about changing the breaks on the E320?

Dale

Benz-O-Rama

There's a great HOWTO on this forum for the W211 brakes. Search the forum and you'll be sure to find it.

W Cole

From my expierience a lot of mechanics will lie to you and say your brakes are worn to try to make a buck. This may not be the case here but be wary.

When the brake pads wear down to a certain spec the sensor is triggered (destroyed in the process).

When doing brakes on the 04 and previous year cars unplug the huge connector going into the sbc unit, set the key aside and lock the doors. When you're done with the brake job, before you start or unlock the car, plug the connector back in. You may get some warning messages but they should go away with either restarting or driving the car.

vettdvr

Correct. I would measure the pads and rotors then compare them to spec before changing. You might not need them yet.


If you do change them be sure to follow the disconnect for the SBC procedures. I do both the Manual steps and then I unplug the SBC.

MB SF

OK, the sensor is a coated wire. When the pads wear down the sensor will first touch the rotor. Then it will wear through the insulation and ground to the rotor completing an electrical circuit and trigerring the light.

The mechanic may have seen that the sensor was touching but not worn through, thus triggering the light.

If that is the case, your light will come on soon once the pads wear a bit more.

Go to the dealer and get new pads AND sensors.

dra5697

So if the sensors were working correctly how would I know the breaks needed to be replaced... is there an alarm or lights that come on in the instr. panel? When the tire was off it looked like the rotor had been worn significantly as well as the brakes being very thin. I assumed the guy in Norfolk was right... I now they just want the money but I was clear that he was not going to do the work and I was going to take it to the dealer then found out the cost... I know... I know if you own the car you should be prepared to pay the price but at those costs I am not prepared to pay when I think I can do it mayself.

So what is this SBC... I have printed both the PDF and the photo but I am not sure I know what I am looking at. Do you disconnect the SBC (whatever that is) by unplugging the large black connector in the picture; and what in the world is a Star Diagnosis as mentioned in the PDF?

dra5697

Got new pads and rotors w/ sensors yesterday... but now I am a little nervous about the change with the SBC and the Star Diagnosis not sure what all that is... I thought it would have been as easy as changing the breaks on my 2003 Tahoe... but I am seeing it is not that easy at all. Thanks for all the input just know that I am absorbing it all like a sponge... and always need more.

W Cole

Small detail but I believe an OPEN circuit triggers the error. So if you're cheap/lazy like me and dont want to make a trip to the dealer you can simply short the two sensor leads together.

Please correct me if I'm wrong, but I did this and no error thus far. I figure having 2 per axle is redundant anyways.

W Cole

Dont let the star diagnostic info in the PDF confuse you - you DO NOT need to do this. Simply unplug the big black connector you mention, lock the car, hide the keys (dont unlock the car or open door/trunk/etc. during the process) and proceed with changing the brakes just like you would on your tahoe. Its not any harder than a normal car.

W Cole

Yes, a light comes on when X amount of pad is remaining, if you search the forums you can find the exact spec, I want to say 1/8" or 3.5mm.

MB SF

You maybe right on the open cicuit. Makes sense.

dra5697

OK every one, thanks for the advice and photos you all posted. I did get teh breaks and the rotors changed out and I am feeling pretty good about saving the money. It only cost me $50.00 for an impact gun, which I may never use again but better to have it then need it in a pinch. Thanks again everyone I am sure I will have other jobs on this car since the warranty is up and I am not paying the dealer for stuff.

E2233

I had my front pads and rotors replaced by an independent garage a couple of days ago. They disable the SBC by locking the car and waiting before doing the work. The garage used all MB parts. They did not bleed the brakes. They lower the car after the installation pumped the breaks five times and start the car. There were no errors on the display. There is no squeaking anymore when I apply the breaks.

W Cole

Congrats man!

I forgot how much new pads were from the stealer. Get this: my mom took her w211 e class in for new brakes (didnt talk to me about it.. wish I could have done it for her) and was charged $150 for LABOR ALONE just to replace rear pads.

This isnt the worste part, they charged her for new sensors even though hers had not gone off yet (I ALWAYS reuse these). And they charged $20 per axle for some sort of "brake kit" I'm assuming this was for anti-squeak compound?? Or maybe its just a completely bogus charge?

E2233

The cost for the MB pads $101.33.
The two front MB rotors $188.18
Two MB brake sensors $21.34
One seal on the driver side $10.66
Labor $104.00
The seal was needed because of the pressure required to pull the rotor on the driver side. The passenger side rotor came off wihout any problems.

vettdvr

That's really not a bad price. For me to do it at home cost about $250 so considering you had someone do it for you they didn't charge excessively. When I had the dealer do the front pads, *no rotors* they charged me $450 which I think it too much for just pads and $4.50 sensors.

cyclrder

how many miles do you have on the car?

I just hit 26K and a ton of it in the city.... outside of town I am pretty hard on them too... while changing back to summer shoes.. I checked my pads and they looked new .......

E2233

December 2005 scheduled service 22,000 miles on my 2003 E500. SA called said break pads front and rear needed to be replaced cost $600.00. He said it was more expensive on the E500 because of the break by wire. He said the whole system had to be shut down and the pads wear out at the same time. I would a little surprise at the price. I had the front pads on by 2000 E320 the cost was less than $250.00 at the same dealer. The mileage on the E320 was about 22,000 and the rear pads were fine.
March 2008 in for warranty repairs at 42,000 miles. SA called said during safety check the front and rear break pads and rotors needed to be replaced total cost over $1,400.
I wanted to use the Akebono Pads, Front: EUR847 with the MB rotors. The tire rack web site defaulted to Premium ATE Original Premium One Pads. The representative on the phone from tire rack said that the Akebono Pads were not available for my year.
Local general service garage said only front pads and rotors needed to be replaced. The garage recommended MB pads and rotors only. I took the car in late in the morning they drop me off at work about three miles and pick up me up in the evening to deliver the car to me.

E2233

The streets and roads in Southern California are very wide with two or more lanes in each direction. I usally coast up to a red light in the right lane and only made a few hard stops. On the 2000 E500 at about 22,000 miles the SA said I needed front and rear brake pads. He told most E500 front pads were being change at about 12,000miles. At 42,000 miles SA said break pads and rotors front and rear needed to be changed. I did not receive a breaking warning. My 2000 E320 at over 60,000 miles has the original rotors. The local general garage had worked on a few MB but none with the SBC. They showed me the pads the wear was almost to the sensor on each pad. There was a lip on both sides of the rotor on the top. I could not tell from feeling the rotors if that was significant wear. The car runs fine and the breaks are firm

vettdvr

My rotors have a lip at the edge of the rotor also but not a problem. When the pads wear to the 1st sensor this is at about 40% pad wear you still have driving left. Many pads are thrown out because the first sensor is triggered. The secret here is to MEASURE the pad thickness and check with the manual before you change the pads. You might be suprised to find pads are changes with many more miles left in them. To change at 12,000 miles pads you really have to drive hard. I lived in S Cal before and it isn't that big an issue. I drive my corvette on the track and the factory pads went 70,000 miles. My E500 front pads were changed at 36,000 miles by the dealer before I started doing my own brakes. Now I know I can get about 70,000 on a front set of MB pads. The MB pads are smaller than the corvette's so they will wear quicker. The brake by wire causes minimal wear on the pads. MB sets the car up so the pads are soft, this saves the rotor, but at the expense of pad wear. So before you change pads on "they need to be changed".. Why not ask what is the thickness and how does it compare to the factory specifications. Then decide to change. Remember also MB does NOT reco. turning rotors and at 70,000 miles I have the origional rotors still going with 40% of the wear surface remaining until they hit the MB spec to replace. So I expect 100000 miles on the origional rotors.

Also in the Owners manual it will indicate the FSS shows a + at the service in window when the brake pads have hit the first sensor. Some new cars might have only 1 sensor so confirm your dimensions to specs before changing

Are we having fun!

E2233

I have the 2003 E500. I think it is the same year as your car. Are there two sensors on each pad?
The garage did not bleed the brakes after the work was complete. They told me that it was not necessary. I noted in an earlier posting that you bled your brakes after to replaced the pads. Is it necessary if the fluid was not exposured? He did pump the brakes five times as the instructions indicated. The instruction did not say it was necessary to bleed the brakes.

vettdvr

There are actually 3 sensors.

1) The Left front has the first set to give the + in the FSS.


2) The right front is set to allow more wear and will give a replace brake warning, don't know exactly as I have changed pads before this is triggered.

3) The remaining sensor is in the rear brake pad set for when to change and will also give a + in the FSS.
But there is only 1 sensor for each pad that has one.

For bleeding I did not bleed the brakes replacing the pads. However I do open the bleed screw and allow the old fluid to purge out of the caliper when I press the the pistons back into the caliper. This allows more fluid to come into the caliper vs having the old fluid. You will have to add top off after purging the old fluid. So technically this isn't bleeding but purging old fluid.

I have been doing this for years as it prevents the "old" fluid from being forced back into the master cylinder and abs system with possible contamination.

So No I haven't bleed the brakes.