DIY Front brake change
Also, which brake pads and rotors would you guys recommend?
I had the dealership replace the rear brake pads 30k miles ago. Do you think i should change out the rear pads and rotors also?
http://www.ideamarketers.com/?Merced...ticleid=500220
or:
First off, the swap is definitely something that anyone can tackle. There really isn't much to it. The vid that Domm posted above shows just how easy it is to do. There are some key differences for our w204s, though, so here goes nothing.
Naturally, standard disclaimer applies: I'm not a licensed/bonded/insured/accredited mechanic. Just someone who wrenches on his own car. Use these steps at your own risk!
1. Break loose the lug bolts. 17mm socket and torque wrench needed.
2. If you're changing rotors as well, turning the steering wheel will be a huge help. If working on the driver's side, turn all the way right. Turn left for the passenger side. Will explain why further down.
2. Jack the car up, using the Reverse Logic Jack Pad if you have it (not affiliated w/ them, just love it for it's simple, but useful design!
3. [personal safety thing] Put an extended jack stand by the jack point. I don't lower the car onto it, just use it as a backup in case the jack fails.
4. Remove the lug bolts and the wheel.
Here's a pic of the whole setup (rotor, caliper, and caliper carrier). Sorry for the obscured 18mm carrier bolt. I had a better pic with the rotor turned for a clearer view of all bolts, but it got corrupted after I deleted the original.

5. Remove the top caliper bolt. Here's the w204 specific difference from the vid above. The caliper is held on by bolt as well as a nut that spins in conjuction. To remove it, you need to hold the 17mm nut in place while you loosen the 13mm bolt. Here's a tip, one that caused me much angst/time. There is not enough room to fit a std 17mm wrench over the nut. You need a small/mini crescent wrench, which is thinner and will slide over the nut. I didn't have one so had to get creative.
6. Remove the lower caliper bolt using the same method as in Step 5.
7. If working on the passenger side, unplug the wear sensor. Skip if working on the driver's side.
8. Wiggle the caliper back and away from the pads.
9. Rest the caliper on something so as to not put pressure on the lines. I used an inverted garden bucket, but use whatever you need to in order to not stretch the lines!
10. Remove the pads by wiggling them out of the guide brackets.
11. Use a big c-clamp to compress the piston back down. Per the video above, using the old inboard pad give the clamp something solid to push against. I've always used thick piece of rubber that covers the entire piston, but you get the idea.
Now if you're only changing pads, skip to Step 19. Next steps cover carrier and rotor removal.
12. Loosen the two 18mm caliper carrier bolts. This is where having the wheel turned (Step 2) before hand is essential. Breaking the bolts loose requires a breaker bar/torque wrench. Because of length of these bars, you will not be able to access the bolts w/o turning the wheel. Once you've broken the bolts loose, do not remove the carrier just yet.
13. Remove the rotor retaining screw. It's a Torx, but the actual size slips my mind ATM. Nothing special though. I had it in my std set.
14. Determine if the rotor has seized/rusted to the hub. If it has, spray some WD40, let soak, then come back with your mallet in hand. My rotors were severly seized because even after WD40, I had to do some major pounding before they broke loose. This is why I stated to only loosen the carrier bolts in Step 12 vs removing the carrier. If you remove the carrier and start whacking away at the rotor, once you break the rust, the rotor is going to fly off the hub and have a good shot at smashing your hand or foot. Leaving the carrier on prevents this.
15. Now remove both 18mm carrier bolts.
16. With one hand, hold the rotor in place while removing the carrier with the other.
17. Put the new rotor on and lock it down w/ the retaining screw.
18. Re-install the carrier, remembering to put Loctite Blue on the bolts.
19. Prepare the new pads - install the old wear sensor into the new pad if it hasn't tripped (passenger side only); otherwise, install the new sensor.
20. Break out your bottle of anti-squeal goo. Use the old pads as a reference to where the inboard/outboard pad will make contact and lay the goo down in a similar pattern, e.g. the inboard pad will need a circular pattern because of the contact w/ the piston.
21. Slide the pads onto guide brackets on the carrier and push them until contact is made w/ the rotor.
22. Slide the caliper onto the carrier/pads. There should be plenty of room if you compressed the piston all the way back.
23. Re-install the caliper bolts, again, using Loctite Blue on the threads. Tighten until the 17mm nut starts to spin. Then using your mini-crescent wrench, hold the nut in place whil tightening the 13mm bolt.
24. Re-connect the wear sensor.
25. Re-install wheel and torque the bolts.
26. Repeat for the other side and you're done.
27. DO NOT FORGET to pump the brake pedal after you've buttoned everything up and put all the tools away. You need to seat the piston/pads to the rotor. Otherwise, you will be in for a rude awakening when you first try to stop the car. This is a very easy step to forget. Something I did years ago that gave me quite a scare since I had slope to my driveway. Nothing worse than that feeling of surprise helplessness. Luckily I remembered to use the parking brake after a moment of panic.
28. Go out and properly bed your pads. I've used the method desribed on Zeckhausen's website for years now and have never had an issue.
So there you have it. Hopefully I haven't left out anything. I'll review it after I post and make edits if needed. Feel free to point things out as well and I'll edit. Looks like I was pretty wordy, but again, this is a very straight-forward job that will give you satisfaction in knowing you saved hundreds of dollars.
Last edited by Doanster; May 7, 2012 at 01:59 AM.
I read old post on here that said they bought the OEM rotors for $100 shipped for two rotors. Where can I find those prices at
Trending Topics
The Best of Mercedes & AMG
http://www.amazon.com/Lisle-24400-Di...6446743&sr=8-1

Seriously, though, I'm all for having the right tools to get the job done... WHEN they're required. In this case, I do have a complete piston compression set since VAG cars have the PITA rear pistons that need to be turned and compressed at the same time.
Breaking out that set is overkill our w204s because then I'd have to fiddle with getting the correct adapter out, etc.
Also, was trying to show how easy this can be with tools most have in the garage vs needing to get a specific tool before hand.

In general, yes, you can do pads only the first change (especially the rears) unless they are warped (which necessitated my swap). Just measure the thickness w/ some digital calipers or old school micrometer to confirm you've got plenty of metal left. The min thickness is stamped on the rotors themselves.
One thing though, before step 11 for resetting the piston, you probably want to take off the cap for the brake fluid so that resetting the piston will not pressure the cap off.
In this case the probability may be low, however when I reset the piston I did notice that the brake fluid leveled up.
In this case the probability may be low, however when I reset the piston I did notice that the brake fluid leveled up.
Short story, if you are going to remove the cap, be sure to clean around it prior to doing so.
Last edited by Doanster; Jul 16, 2012 at 12:13 PM.


