Hi all, I just finished the front pad and rotor replacement on my E55. I thought i would do a quick writeup so you know what you'll need before going down this road. I didn't think to write it up until I was finished, but it's not difficult or hard to figure out as long as you have the right tools.

Tools needed:
Ratchet-preferably with a long handle
Lug wrench(duh)
10mm hex bit(caliper bolts)
T30 Torx bit, hardened if you can get one(rotor screw)
Pin punch for retaining pins
E10 inverted torx bit(pad sensor connector bolt)
A good size hammer(for knocking the rotor loose)
Torch(better have it just in case!)
Penetrating lube
Large flathead screwdriver

My car had 112K on it with the stock rotors, so it was pretty much a worse-case scenario. I managed to pick up 2 rotors fom Parts.com for $230 shipped to my door and a set of Akebono pads for $130ish from another online vendor. You may also want to purchase 2 pad sensors. I did not, but they're cheap.

IMPORTANT: Unplug the connector to the SBC unit!

Raise and support the car, and remove the wheel.
Remove the bolt for the pad sensor and pull the sensor out of the pad.
Drive the pins halfway out with the punch and remove the pad retraining springs. Remove the pins the rest of the way and set aside.

Use the screwdriver to carefully push the pads back and compress the pistons. If the pads are stuck, use the hammer to tap the screwdriver and get them moving. Then insert the screwdriver between each pad and the rotor to push all 4 back. You may wish to crack the bleeder screw, in which case I believe you'll need a 10mm socket or wrench. I did not and was fine.

Try to pull the pads out. If they're stuck, wait until you get the caliper off and tap them out after you flip the caliper over.
Find the two hex bolts holding the caliper to the bracket. They face the front of the car. Use the 10mm hex bot and ratchet to remove the bolt. They willl be fairly difficult to turn due to the locking compound on them.
Remove the caliper and remove the pads if you haven't done so. Support the caliper somehow so it doesn't pull on the line. I set mine on a small cardboard box that I had which worked great.

Now all that's holding the rotor in place is the T30 bolt and a fair amount of rust. Spray the bolt with the lube and heat the crap out of it with the torch before you even try to break it loose. If all else fails you may have to drill it out or get a sharp chisel and hammer to try to spin it out.
Once it's out, smack the hub of the rotor in a couple of spots very forcefully to break it loose from the hub. You do not have to beat on the backside of the rotor. Two or three strong whacks broke both of mine loose.

Clean up the hub as best you can, install the new rotor and tighten the screw back in place if you wish. You can leave it out, but if the rotor moves on the hub it'll make lugnut installation difficult.
Place the caliper over the rotor and tighten both bolts. You may wish to use some Locktite on the bolts. I don't have a torque wrench but I got them TIGHT.

Clean the pad slides on the caliper as best you can and use the supplied lube or some anti-seize sparingly on the contact points. Slide all 4 pads in, and reinstall the springs and pins, tapping them in until they bottom out.

Install the pad sensor into the pad and secure the wiring to the backside of the rotor with the bolt. Reinstall the wheel, and then repeat the process on the other side. There, you've done it!

Reconnect the SBC connector, start the car, press the brake pedal a few times, and move the sar slowly forward and back to make sure the pads are contacting the rotor. If you get any error messages, shut the car off and restart. They should go away once the SBC unit is happy.

Now go break in your pads according to the manufacturer. I took a nice writeup from StopTech and followed it. I warmed up the brakes and then did about 8 hard stops from 60 to 15mph or so in fairly quick succession then cruised down the road for a few minutes to let the brakes cool. The rotors had a nice even transfer coating on the them and the car stops like a monster!


Please feel free to add your own comments or point out where I may have given incorrect information. I hope this helps!

Izzy

 

Very nice write-up. Seems similar to a Porsche pad and rotor replacement I've done. I'm no mechanic and I found this job to be very easy. Thanks for the write-up.

 

SBC pump does not need to be unplugged PERIOD. I too just changed all pads and front rotors. I was advised by my MB tech that as long as the doors are not touched you will be fine changing out the pads. He calls it sleep mode, when the car is turned off after a min and the light in the dash goes off you are good to go.

 

Only a fool would NOT disconnect the SBC, There is NOTHING to be gained by not disconnecting the pump and HUGE issues if the car wakes up and the calipers are off and the pads are out.

 

+1 that would be correct procedure.

 

It's very easy to forget and open a door to turn the wheels the other way or grap your new brake pads out of the car(or have the dog step on the remote). I like to think I'm not an idiot, but a mistake like that could cost you fingers and a nightmare when all of your pistons come shooting out of the calipers. It takes literally 10 seconds to pop the hood and disconnect the SBC unit. I even started mine with the plug disconnected to turn the wheels the other way. I got all kinds of errors on the cluster, but they all went away when I was finished and the pump was plugged back in and the car restarted.

 

I went searching for a diagram about deactivating the SBC and found this.

http://www.scribd.com/doc/14094997/M...ke-Control-SBC

However it doesn't actually indicate how to disconnect the pump. I haven't taken the time to go look under the hood either, but was curious by what means you are disconnecting the pump? Pulling a fuse, actually pulling the connector off the pump? Sorry for the knob questions, but I just want to make sure I'm knowledgable on this topic.

 

Again, was advised by someone in the know. Left my wheels straight , locked the doors and keys in the house. Two hours later job done....... No issues. Disconnection is not necessary.

 

I would consider myself as "someone in the know" and if you can't deactivate the SBC system with a SDS, like I always do, then unplugging it is satisfactory.

NEVER NEVER NEVER work on the SBC without doing these 2 things. While putting it into sleep mode and putting the keys in the house will also work, there are intangibles and tangibles. The tangibles you can control(deactivating with SDS or disconnecting the connector) or the intangibles you can't control because you chose not to do either of the above 2 items(someone waking up the car and your fingers getting FLATTENED).

Better safe than sorry! IMHO

 

There is a huge black connector on the back side of the unit. Pull up on the release at the top as you slide the connector back. Make sure you pull it all the way up and out of the way, don't just unseat it. You may have to wiggle the wiring a little to get it to come out(the harness is stiff), but it takes literally five seconds.

 

Thanks greatly for the write-up.

 

Good write up, though did you really install new pads on used rotors with out turning/ cutting them?

 

Glad I read the SBC needs to be disabled when doing this. Never would have guessed the brakes are applied when you unlock, or open the door. I'm sure there's some reasoning behind this, perhaps safety, maybe just a system check? Wondering why it does this though. As I said, never would have expected it.

 

Sure, why not? The rotors had acceptable runout and some wear(at 80K when I first did the pads), but there was no compelling reason for me to replace or cut them at the time. Of course it is always best to do so, but not always necessary.

 

Have the whole list

http://www.mercedestechstore.com/pdfs/index.htm

 

New pads require a flat smooth surface to work properly. Worn rotors with grooves will cause premature and uneven wear on the new pads. Risking the pad to wear unevenly from top to bottom. This can cause the pad backing plate to grind in to the rotor. Also the pads will not work as efficiently compared to if they were installed with cut or new rotors.

 

Have xtra new front set of akebono pads EUR983... $130 shipped

 

thanks for the DIY. After installing new pads the cluster went nuts w RED warning about breaks. Is it safe to take it out and drive it? How do you reset the brake lights? I assume this is because i disconnected the SBC when installing the pads.

 

BOSSSSSS!!!! Thanks for that!

 

Nevernind. Goes away on its own.

 

Nice write up izzy, thanks very much!!

 

Izzy,

Thanks for the thread, I thought it was a great write up!!