Brake Pad DIY notes
 

At a little over 20k miles, I got the brake sensor warning light. Both the fronts and the rears were getting very low, so I ordered new pads and rotors for all 4 corners, as well as 2 new wear sensors.


Yesterday, I tackled the fronts, with the rears to come next weekend. Since I didn’t see a DIY thread, I figured I would at least type some very quick notes for anyone who will tackle this. Sorry there were no pictures, I was doing it between commercials of the Rolex 24 hours of Daytona race, so, no time for pictures.


I did see Rock Auto finally has some aftermarket pads, but I stuck with OEM, and the Mercedes branded parts I received came from the following countries:

Front Pads: Czech Republic

Rear Pads: Italy

Rotors: Poland


The front brakes are super easy. They are the kind where you tap out the pins, slide the pads out the back, replace, and go.


The minimum thickness stamped on the rotors is 34mm. The new ones were around 37.4, and the ones on the car came in around 35.5. It is likely I’ll be under the minimum at the next pad change, so I debated for a while, but decided to leave the old rotors on the car, and replace them at next change, since they are still 1.4 mm over. There was a noticable outer lip, but otherwise the front rotors looked great.


For the fronts pad change (note I’m leaving off the obvious safety and cleaning stuff like jackstands, wheel chocks, using brake clean on your parts, torquing wheels, etc….these are quick notes, be safe when doing it yourself)


It is very helpful to turn the wheel so you can access the rotors as best as possible.

• Jack up/jack stands and remove wheel.
  
• You’ll see two pins on the calipers. From the back side of the calipers, there you’ll see a cotter--type wire that goes through both pins as well as into a little groove in the caliper. Remove this with needle nose pliers. The wire will get a little deformed with removal and reinstall, I think I’ll order new ones for the next pad replacement.
  
• Once the wire is removed, gently tap the pins from the back of the caliper. Once you get them pushed out a little, you can use the needle nose to pull it out from the front.
  
• Once both pins or out, the retaining clip will probably just fall right to the floor
  
• Once the clip and pins are out, you can pull the pads out the back. It will be hard to get them out, just pulling. Since you’ll need to compress the caliper pistons (4 on the fronts) anyway, I found the best thing to do is to use a C-clamp. There will be a spot on the top and bottom of the pad where you can get one end of the clamp on the old pad and the other on the back/front of the caliper. Remove the brake fluid reservoir cap, taking out fluid if needed, then working evenly, compress the pads to push in the pistons. The old pads will now pull right out.
  
• Insert the new pads, push the pins back in, attach the retaining clip, and the cotter wire and you are good to go.
  
• The brake wear sensor is on the inboard passenger pad, and it attaches easily to the wire and gets placed into a hole in the pad.
  
• Note, where the brake pad sensor attaches may be in the way for re-inserting that pad. It is held on via a reverse torx (e10) screw, so that is the only unusual tool you’ll need.
  

If you are in a hurry, this is only a 1 beer job. I took the time to clean the calipers, inside/backs of of the wheel, and such to stretch it to 2 (or 3). Tools needed are nothing more than jack, stands, torque wrench for wheels, needle nose pliers, and small hammer for pad change, c clamp to compress the pistons and the e10 for the sensor.


Removing the caliper to replace the rotors would require a little more.


I’ll post when I get to the backs, which will be slightly more complicated since you need to slide the caliper off, and go through the brake release procedure in the dash.

Tackled the rear this weekend. The rear rotors were hardly worn at all. Minimum thickness is 21.4, new was 24.3, used was 24.0. Think they will be fine for a while.

The rears are the same as they've been on plenty of other C classes I believe, so any DIY you find should work.

If you are not changing rotors:

After safely jacked and wheels removed:

• Using the steering wheel controls, put the car in brake service mode and retract the pads. There is video on youtube. The trick here is to hold the buttons while the odometer was displaying I was trying to do it from another screen and didn't get it to work for a while.
• Remove dust caps on the backside of the slider pins
• (passenger side only) use reverse torx (e10) to remove brake wear sensor and disconnect from pads
• Use torx (think it was t45?) to remove the slider pins
• remove positioning clips with flat head scewdriver
• slide off calipers and hang so brake lines are not stressed
• remove pads
• Insert wear sensor (passenger side inboard only
• Insert pads onto rotors
• Remove fluid cap and compress piston (large single piston in the back, if you use C clamps like I do, you need a decent size one)
• Slide calipers back on
• Reinsert slide pins (I applied some brake pin lube) and tighten, recap, reattach wear sensor, reattach positioning clip.
• After completing both sides, re-engage brakes from steering wheel controls.

Relatively quick once I figured out how to retract the pads from the steering wheel (and inserted the right size torx into the slider pins, got it wrong the first time and it jammed in there.

Tools were t45 torx (I think), e10 reverse torx, flathead screwdriver, c-lclamp, and the jack stands, torque wrench for wheels, etc...

All in all, a pretty easy pad change. Rotors, as always will definitely be harder, rears looked like 2 18 mm bolts that need to be removed and are on there tight (as they are spected to be). Seems like rear rotors will last quite a while if the pattern holds, but I'll need to use the new fronts at the next pad change.

Also, I should note that as any C450/43 owner knows, these pads are very dusty. Clothes and tools got pretty nasty, more than most brake pads I've done and all needed a good cleaning.

Since my rotors were not used, the grand total for my front and rear pad change (front pads, rear pads, wear sensors for both) was $162, with another $400 in rotors sitting in the box for next time.

Thanks for the write-up! Do you have the part number that you used for the rear pads? I used a part finder tool from a Mercedes dealer online and got 000-420-82-00. It looked the same as my old pads, but it was only making contact with the inside 2/3 of the rotor. I went to another dealer and used its tool to find 000-420-59-00. I just want to make sure if anyone used the same part. Also, I read somewhere else that you have to take the sway bar link off to change the rear rotors on the C450. Can you tell if this is true? Thank you very much in advance.

Yes, the rear pads I used were # 000-420-59-00

From memory, I didn't note that it was obvious the you needed to remove the sway bar link to get to rear rotors, but since my rear rotors were totally fine, I didn't check if the clearance was there to fully remove the bolts. My previous (non MB car) had clearance issues getting to the caliper bracket bolts, but I was able to use a jack to get the right amount of suspension load to have clear access. There's a lot of travel from fully unloaded on jack stands to fully loaded, so hopefully there is a position that works, although I can't be positive.

This should be a sticky!



Thanx for this

Since it was asked and the thread has been revived, here are the parts I used. Prices are from one of the on-line discount Mercedes Dealers at the time I purchased.
https://cimg3.ibsrv.net/gimg/www.mbw...2a8227dbb2.jpg

Just need to go into service menu and enter rear brake service mode.

No software needed.

I referenced the video to show you how to get into brake service mode in the initial post. Here is the video

Does anyone know approximately what percentage of pads are left when pad sensor is triggered? I think it'll be enough to drive around for a few days before new pads are delivered but I just want to be sure. I don't want to order parts in advance.

Drive around until brakes starts to squeak. Then the low brake warning metal will start to scrape the rotors. If you think your rear is low, and want to press it, fine but I wouldn't do it to the front rotors. They expensive.

There is some pad life when the wear sensors go off. Certainly enough for a "Few days" unless you make a cross country trip in those few days. I measured them when I pulled them off, but don't see my notes. As a guess, probably 2.5-3 mm left. Definitely time to replace, but definitely not an emergency, they weren't at the backing plate or anything.

The one thing to note is that the sensor is only on 1 of the 4 pads on each axle, so if you have uneven wear (which has been reported by several people on this forum) you may need pads before the sensor goes off. That was not my case and should not happen much in theory (unless you drive on ovals like NASCAR and have stability control kick in on one side only) but others here did report having some uneven wear.

I am attempting to change my pads and have not done brakes in a while but it is crazy to need this after only 25K miles. Can someone verify if you have to unbo,lt the front calipers to remove pads and compress pistons and if so, what size is the hex socket? I am going to have to go and get one if so.

The first post has instructions for the fronts. If you are just doing pads it’s just pins not bolts.

I actually found it easier to remove the caliper in order to press the pistons in for the new pads and also clean the calipers up to remove old brake dust.. I think the two bolts were 20mm? Now I just need to see a photo of how the outer shim goes back and I am golden!

Finished the second side without removing the caliper but did take the Time to clean caliper really well before reassembling. Did the backs and everything is great. Been a week and incredible reduction in brake dust without compromising stopping power. Very happy, almost makes up for having to change pads as 26K miles!

My light finally came on (front pads, back is fine) so I just placed the order and they be here on Thursday. It is hard to see but seems like I have a couple of mm left, plus braking is still smooth and normal. Going to be in eco mode for a few days until I get pads. :tear::tear::tear:

You'll have plenty of pad for a little bit, don't worry about how you drive if its a few day. Plus, you'll get more engine braking in sport mode than Eco, so it may even be helpful to the brakes to use sport mode :)

went 45000 miles w/o needing to change mine. Sport + - downshifting and traction off most of the time.

but i also used autopilot/adaptive cruise for many highway miles

If his sole idea is to save, what about extra wear and tear from engine braking on the engine? Better to spend $100 on pads vs $10000 on a new engine.

Don't go sport/sport+ if you only want to engine brake more. You will eventually do the rodeo buckling action which is annoying at wrong time. Stay comfort mode unless you want the faster response from sport+

Thanks a lot for the write up. I am going to tackle this soon. Kinda hoping you wrote about the rotors too. Also how did jack the car up and where did you put the jack stands?

Just to be sure: Does the part number for the front pads vary based on VIN? I've already ordered the pads on Amazon and all I entered was my make, model and year; but I just talked to a service adviser and she was asking me for last digits of VIN to give me an exact quote.

He's trying to save wear for a few days since his vehicle is already at the wear indicators....not for the life of the car.

That said, I drive in Sport 90% of the time. There is not any extra wear on the engine while engine braking, particularly on a manner per-programmed into the transmission. While super high loads on the engine may wear the rings slightly more (so you'll get 200,000 miles out of the engine instead of 200,100) the loads in something like sport mode are small and probably not measurable to the wear.

You can borrow my jack puck if yours don't come in time to change the brakes. All you need to do is jack one corner to do the one brake.

For rotors, get the Euro spec rotors from Rockauto.

Sorry about the no info on the rotors, I simply didn't need to do them. I'm getting pretty close on the fronts again and will do the rotors this time, but probably still several months away.

There are jack/jack stand points on the outer rails and even a little plastic clip on the rocker to remove to give you more room as a front center puck you can use (with a hockey puck or something). I think I used the rear diff in the rear to jack with the stands at the rails.

Dealer systems for many manufacturers generally lookup part numbers by VIN, so they ensure they have the correct part as some parts will be VIN specific. I don't believe there is anything VIN specific for the pads, you should be fine.