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Pelican Technical Article:
Front Brake Pad and Disc Replacement

Jared Fenton
 

 
Time: 2 hours
Tab: $200
Talent:  
Tools:
Torx bits, screwdrivers, sockets
Applicable Models:
W210 E320 (1996-02)
W210 E300 (1996-97)
W210 E420 (1997)
W210 E430 (1998-99)
W210 E55 (1998-02)
Parts Required:
New pads and rotors
Hot Tip:
Pre-soak rusted bolts in penetrant oil
Performance Gain:
Car stops better
Complementary Modification:
Replace wheel bearings
 
   

   

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     Replacing your brake pads is one of the easiest jobs to perform on your Mercedes-Benz. In general, you should inspect your brake pads about every 25,000 miles, and replace them if the material lining of the pad is worn down enough to trigger the pad replacement sensor.  In reality, most people don’t inspect their pads very often, and usually wait until they see the little brake-warning lamp appear on the dashboard. It's a wise idea to replace the pads, and inspect your discs as soon as you see that warning lamp go on.

      If you ignore the warning lamp, you may indeed get to the point of metal on metal contact, where the metal backing of the pads are contacting the brake discs. Using the brakes during this condition will not only give you inadequate braking, but will also begin to wear grooves in your brake discs. Once the discs are grooved, they are damaged, and there is often no way to repair them. Resurfacing will sometimes work, but often the groove cut will be deeper than is allowed by OEM specifications. The smart thing to do is to avoid this problem replace your pads right away.

     The procedure for replacing pads on all the wheels is basically the same. There are slight configuration differences between front and rear brakes, but in general the procedure for replacement is similar. The first step is to jack up the car and remove the road wheel.  This will expose the brake caliper that presses the pads against the disc.  Make sure that the parking brake is off when you start to work on the pads.

     If you look inside the caliper, you will see the brake pads - usually they will look very thin. To replace the front brake pads on the Mercedes W210, you need to remove the caliper. Begin by removing the brake pad retaining clip which keeps the pads from rattling by using a screwdriver (See Figure 2). Make sure you wear safety glasses during this step, as the clip can come flying off if you're not careful. 

     Please note that Mercedes-Benz recommends flushing the brake fluid every two years for durability.

     Use a screwdriver to pry out the small plastic caps that cover each caliper guide bolt (See Figure 3). Next, remove both of the 7mm guide bolts from the caliper (See Figure 4 and Figure 5 ). Now remove the 5mm hex bolt holding the brake wear sensor to the caliper, then pull the electrical connection for the brake wear sensor apart (driver’s side in the front, passenger side in the rear) (see Figure 6 and Figure 7 ).

     After the guide bolts have been removed, you should be able to simply lift the caliper off of its mount (See Figure 8). If not, you can very carefully pry the caliper off using a screwdriver. Take your time and pry both sides of the caliper equally. At this point, you can remove the outer brake pad from the caliper, and use a screwdriver to pry the inner pad out of the caliper piston (See Figure 9). Suspend the caliper using some zip-ties or rope until you are ready to work with it again. Don't let the caliper hang from its rubber hose (this can damage the brake line) (See Figure 10).

     Once you have the pads removed, inspect the inside of the caliper.  You should clean this area with some compressed air and isopropyl alcohol. Make sure that the dust boots and the clamping rings inside the caliper are not ripped or damaged.  If they are, then the caliper may need to be rebuilt. At this point, you should inspect the brake discs carefully.  Using a micrometer, take a measurement of the disc thickness.  If the disc is worn beyond its specifications, then it’s time to replace it along with the one on the other side (see Project on replacing brake discs). In our case, we decided to replace the brake discs at the same time as the pads.

     After the caliper is removed and tied out of the way, you must remove the caliper bracket. This is secured to the back of the knuckle with two 19mm bolts (See Figure 11). They are torqued down very tightly, so you may need to use a breaker bar in order to get them loosened. Once you have removed the bolts, guide the bracket over the brake disc and out of the way. Once the bracket is removed, you’ll be able to remove the disc.

     The disc is held to the hub with a countersunk 5mm hex screw that is generally replaced at every service. This screw is usually not very tight and you can break it loose holding the disc by hand. Remove the screw and the disc should just come off. Sometimes, corrosion can cause the disc to stick to the hub. If it is stuck on, use a hammer on the backside to knock the disc off (Figure 12 and Figure 13 ). If there is corrosion on the bearing flange to rotor mating surface it must be removed at this time or you will have brake rotor run-out issues.

     Before installation, lightly grease the brake DISC where it contacts the bearing flange with anti-seize compound.

     Installation of the new brake disc is a snap; simply push it onto the hub, taking care to line up the holes for both the lug bolts and the brake retaining screw. Put a small dab of anti-seize compound on the threads of the new retaining bolt. This is cheap insurance to prevent the screw from stripping the next time you remove it. Torque the screw to 10 NM = 7.37 ft lbs (See Figure 14).

     To install the new brake pads, you will need to take a C-clamp and push the caliper piston back into the caliper. This is because the new pads are going to be quite a bit thicker than the old worn-out ones, and the piston is set in the old pad’s position.  Push back the piston using the clamp, being careful not to use too much force.  Using a screwdriver here can accidentally damage the dust boot and seals inside the caliper, and is not recommended (See Figure 15).

     Be aware that as you push back the pistons in the calipers, you will cause the level of the brake reservoir to rise.  Make sure that you don’t have too much fluid in your reservoir.  If the level is high, you may have to siphon out a bit from the reservoir to prevent it from overflowing.  Also make sure that you have the cap securely fastened to the top of reservoir. Failure to do this may result in brake fluid accidentally spilling onto your paint.

     Install the caliper Bracket over the new brake disc and bolt it onto the knuckle. Torque the fasteners to 115 NM = 84.8 ft/lbs. Now set the outboard brake pad onto the caliper bracket. (See Figure 16 and Figure 17 ). Before you can fit the inner brake pad inside the caliper, fit a new brake wear sensor or transfer the old sensor to the brake pad. When the pad wears down enough to break through the plastic sensor, the circuit is completed giving the brake light on the dash a ground. Use a pair of needle-nose pliers to pull out the old sensor if you plan to re-use it. With a new sensor, simply push it into the hole on the pad as seen here. Once the caliper is mounted to the bracket, plug the sensor back into the harness (See Figure 18). Now snap the inner brake pad into place using your hand (See Figure 19).

     You also may want to spray the back of the brake pads with some anti-squeal glue.  This glue basically keeps the pads and the piston glued together, and prevents noisy vibration. Anti-squeal pads can also be purchased as sheets that are peeled off and placed on the rear of the pads.

     Install the caliper onto its mounting bracket, surrounding the brake disc.  If the caliper won't fit, then you need to push in the piston a bit more until the space in-between both pads is wide enough for the brake disc to fit. Tighten down the guide bolts using a torque wrench to between 18-22 ft-lbs. (25-30 Nm). Re-fit the protective caps back over the guide bolts and lastly, re-fit the spring clip on the front of the caliper. Reinstall the 5mm hex bolt holding the brake pad wear sensor to the side of the caliper. Don’t forget to re-connect the electrical portion as well (See Figure 20).

     When finished with both sides, press on the brake pedal repeatedly to make sure that the pads and the pistons seat properly. Also make sure that you top off the master cylinder brake fluid reservoir if necessary. Brake pads typically take between 100 and 200 miles to completely break in.  It’s typical for braking performance to suffer slightly as the pads begin their wear-in period. Make sure that you avoid any heavy braking or emergency maneuvers during this period.
Replacing your brake pads is one of the easiest jobs to perform on your car.
Figure 1
Replacing your brake pads is one of the easiest jobs to perform on your car. In general, you should inspect your brake pads about every 25,000 miles, and replace them if the material lining of the pad is worn down enough to trigger the pad replacement sensor.  In reality, most people don’t inspect their pads very often, and usually wait until they see the little brake-warning lamp appear on the dashboard.  It's a wise idea to replace the pads, and inspect your discs as soon as you see that warning lamp go on.
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Using a screwdriver, pry out the retaining spring on the front of the caliper.
Figure 2
Using a screwdriver, pry out the retaining spring on the front of the caliper. It’s a good idea to use safety goggles as this spring is under tension.
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This photo shows the upper protective cap being pried out of the cover for the caliper guide bolt.
Figure 3
This photo shows the upper protective cap being pried out of the cover for the caliper guide bolt. (green arrow) There are two caps, one for the upper and lower bolts.
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With the caps removed, you can loosen the caliper guide bolts using a 7mm hex key socket.
Figure 4
With the caps removed, you can loosen the caliper guide bolts using a 7mm hex key socket. You don’t need to remove them completely from the tubes, just enough to free the caliper from the bracket. This picture shows the location of the lower mounting bolt.
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ThisPicture shows the location of the upper caliper guide bolt.
Figure 5
This picture shows the location of the upper caliper guide bolt.
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At this point, you should also remove the 5mm hex bolt holding the brake wear sensor connector to the caliper.
Figure 6
At this point, you should also remove the 5mm hex bolt holding the brake wear sensor connector to the caliper.
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Once released, pull the connector for the brake wear sensor apart.
Figure 7
Once released, pull the connector for the brake wear sensor apart.
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With the caliper guide bolts and retaining spring removed, you should be able to lift the caliper off its bracket.
Figure 8
With the caliper guide bolts and retaining spring removed, you should be able to lift the caliper off its bracket. If it’s stuck on there, you can use a screwdriver to carefully pry the caliper up and off.
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With the caliper removed, simply pry the brake pad out of the piston inside the caliper.
Figure 9
With the caliper removed, simply pry the brake pad out of the piston inside the caliper. Once removed, check the dust seals around the piston for cracks or damage. Also clean the inside of the caliper with isopropyl alcohol and compressed air.
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It's a good idea to suspend the brake caliper out of the way with some zip ties or rope when you are not working with it.
Figure 10
It's a good idea to suspend the brake caliper out of the way with some zip ties or rope when you are not working with it. Never support it just with the brake line: this can damage the line.
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ThisPicture shows the two 19mm bolts that secure the caliper bracket to the steering knuckle.
Figure 11
This picture shows the two 19mm bolts that secure the caliper bracket to the steering knuckle. This bracket must be removed before the disc can come off. These bolts are torqued down very tight, so you may need to use a breaker bar to loosen them up. Once the bolts are removed, slip the bracket off and set it aside.
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The brake disc is secured to the wheel hub with a countersunk 5mm hex bolt.
Figure 12
The brake disc is secured to the wheel hub with a countersunk 5mm hex bolt. Once removed, the brake disc should simply pull off. Sometimes, the disc can stick to the wheel hub. If it is stuck on, use a hammer on the backside to knock the disc off. If it’s really stuck on there, you may need to spray the disc surface with penetrant oil and let it soak in overnight.
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This is what you should see once the brake disc has been removed from the wheel hub.
Figure 13
This is what you should see once the brake disc has been removed from the wheel hub. If there is corrosion on the bearing flange to rotor mating surface it must be removed at this time or you will have brake rotor run-out issues. I suggest you sand it off and coat the surface with some anti-seize compound.
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Shown here is the new brake disc fitted to the wheel hub.
Figure 14
Shown here is the new brake disc fitted to the wheel hub. It's a good idea to put a small dab of anti-seize compound on the threads of the new disc retaining bolt before installing it. Then, line up the new disc with the mounting hole on the hub. You will likely have to hold the disc in place until the bolt starts threading in.
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Before you can install the new brake pads on the front, you will need to push the piston back into the caliper.
Figure 15
Before you can install the new brake pads on the front, you will need to push the piston back into the caliper. In this case, a large C-clamp works well. Make sure to seat the face of the clamp on the inside of the piston and also solidly on the rear of the caliper. Make sure that the piston retracts into the bore evenly. If you encounter any resistance, stop and check that you aren’t cocking the piston in the bore.
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Install the caliper mounting bracket to the steering knuckle and torque the mounting bolts to 115 NM = 84.
Figure 16
Install the caliper mounting bracket to the steering knuckle and torque the mounting bolts to 115 NM = 84.8 ft/lbs..
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Fit the outer brake pad on the caliper frame as shown here.
Figure 17
Fit the outer brake pad on the caliper frame as shown here.
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Before you can fit the inner brake pad inside the caliper, you'll want to either fit a new brake wear sensor or transfer the old sensor to the new brake pad.
Figure 18
Before you can fit the inner brake pad inside the caliper, you'll want to either fit a new brake wear sensor or transfer the old sensor to the new brake pad. When the pad wears down enough to break through the plastic sensor, the circuit is completed giving the brake light on the dash a ground. Use a pair of needle-nose pliers to pull out the old sensor if you plan to re-use it. With a new sensor, simply push it into the hole on the pad as seen here. Once the caliper is mounted back over the bracket, plug the sensor back into the harness.
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Remove the ties holding the caliper up to the frame of the car and fit the inner brake pad to the inside of the caliper piston.
Figure 19
Remove the ties holding the caliper up to the frame of the car and fit the inner brake pad to the inside of the caliper piston. It is held in place by a spring clip that may take a little effort to seat. Route the wiring for the brake pad sensor through the top of the caliper.
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Mount the caliper back over the new pad and disc, line up the caliper guide bolts and torque the caliper guide bolts back down to the bracket 18-22 ft-lbs.
Figure 20

Mount the caliper back over the new pad and disc, line up the caliper guide bolts and torque the caliper guide bolts back down to the bracket 18-22 ft-lbs. (25-30 Nm). Re-fit the protective caps back over the guide bolts and lastly, re-fit the spring clip. You install one end of the clip, then twist it while tensioning, then install the other end. Once both ends are in the caliper, push it in until properly seated on the front of the caliper. When finished with both sides, press on the brake pedal repeatedly to make sure that the pads and the pistons seat properly. Also make sure that you top off the master cylinder brake fluid reservoir if necessary. Brake pads typically take between 100 and 200 miles to completely break in. It’s typical for braking performance to suffer slightly as the pads begin their wear-in period. Make sure that you avoid any heavy braking or emergency maneuvers during this period.

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Comments and Suggestions:
DJ Comments: How similar is this procedure for a 2007 SLK350? Any more current tech articles for that model & year?
June 3, 2014
  Followup from the Pelican Staff: It is different, your vehicle may require use of a scan tool. All of our Mercedes-Benz tech articles are located here:
http://www.pelicanparts.com/techarticles/Mercedes-Benz/MBZ_Tech_Index.htm - Nick at Pelican Parts
 
JH Comments: With a mallet
May 30, 2014
  Followup from the Pelican Staff: No. - Nick at Pelican Parts  
JH Comments: How do u get spring clip back on?
May 30, 2014
  Followup from the Pelican Staff: You install one end of the clip, then twist is while tensioning, then install the other end. Once both ends are in caliper, push it in until properly seated. - Nick at Pelican Parts  
mariaweerts82 Comments: What tools are needed for a 1994 Mercedes sl400 brake job
May 21, 2014
  Followup from the Pelican Staff: We don't currently have a tech article for that vehicle. I don't have a place to source the needed tools from, other than out tech articles. - Nick at Pelican Parts  
Coop Dawg Comments: Really appreciate this information that has been given it makes the job a great deal easier Thank You.
May 14, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
luis Comments: hi i had a question, the service i was interested was on a 2007 mercedes E350 front brake pads and wheel bearings, looking for a quote . thank you
May 11, 2014
  Followup from the Pelican Staff: Give our parts specialists a call at 1-888-280-7799. They can help you find the right parts.
- Nick at Pelican Parts
 
oiram Comments: i worked on my 1985 380 se model transmission drain the oil and filter replaced ... when i noticed my old fluid maybe half a gallon drained i look at the manual book it said 8 liter capacity then i refilled it about 6 liter but when i check it the dip stick way too much ? any suggestion?
May 11, 2014
  Followup from the Pelican Staff: I would start by adding the amount that was draining. Then check the level and top up as needed. - Nick at Pelican Parts  
97E320 Comments: The article says Torx bolts. I don't see them in the write up. Can you explain?
March 23, 2014
  Followup from the Pelican Staff: I think this is an error. I will have the Pelican Team look into it. - Nick at Pelican Parts  
Parvez Comments: I am planning to replace brake pads on my 2005 E320CDI and during the research saw a reference to SBC. What is it? Where is it? All DIYers make not be qualified mechanics, so please explain any special steps needed for different models, like 'notes' to the very detailed pictures and procedures above. I will appreciate a quick response. Thanks.
March 20, 2014
  Followup from the Pelican Staff: This article only applies to:
W210 E320 (1996-02)
W210 E300 (1996-97)
W210 E420 (1997)
W210 E430 (1998-99)
W210 E55 (1998-02)

SBC is sensotronic brake controls. The system needs to be deactivated before working on the brakes, or personal injury can occur. If you feel you need mre guidance, I would buy a Mercedes-Benz repair manual. It will have the procedure, special tools and torqu - Nick at Pelican Parts
 
CrashTank12 Comments: These instructions were very helpful with working on my W210 E320 '01, especially the pictures very nice!. I have done brakes on vehicles for about the last 20yrs...but this was the first time on a Benz. Your site provided a great place to start the job, & get it done right.
One caveat - "Now remove the 5mm hex bolt holding the brake wear sensor to the caliper,..." Should actually be 6mm. Or at least it was on mine.
Aside from that everything went went well!
February 7, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
uberwgn Comments: Very helpful to have this info. I've done brakes on MBz before but it was nice to have a refresher prior to starting the job. Everything went as smooth as possible!

Thanks again.
January 14, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
Scott Comments: Excellent article. Thanks for the info.

Do you have links for 2010 MB C300 Sprot Front pads and rotors? I have cross-drilled rotors on the front.

Thanks.
January 14, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
Give our parts specialists a call at 1-888-280-7799. They can help you find the right part.
- Nick at Pelican Parts
 
bong Comments: what can I say! excellent web site, will save us from hardship from the job itself and the money savings
December 27, 2013
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
Toy Comments: Is it automatic to replace the rotors when pads are replaced?
2008 ML550 36K miles.
September 4, 2013
  Followup from the Pelican Staff: Depends on the rotor condition. I only replce the rotors if they are at or below spec. A good rule of thumb is, if the rotor has a large ridge around the outside of the braking surface, it will likely require rotors. Always measure them to be sure. - Nick at Pelican Parts  
SilberUrS6 Comments: Excellent write up - great pictures and descriptions.

The torque specs were very nice to have.
August 17, 2013
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help. - Nick at Pelican Parts  
Harley Ryder Comments: I applied this brake R & R to my W202 '98 C280 and it worked out great. The torque specs helped the most. Suggestion: when pressing the caliper piston back inside, leave the old brake pad in place to push against so there is no chance of damage to the piston. Thank you!
June 6, 2013
  Followup from the Pelican Staff: Glad this DIY helped you.
-whunter
 
MT Comments: Note that while these instructions are for the W210, they also come up on W211 results. On 2003-2006 W211, you need to disable SBC before touching any part of the brakes!
April 17, 2013
  Followup from the Pelican Staff: Duplication, already answered.
roy@pelicanparts.com
 
nancee Comments: How can I a reliable honest machnic too replace my brake pads on a 2005 s class. the dealership wants $700. outrageous. in Orange County ca.
March 23, 2013
  Followup from the Pelican Staff: I suggest you look here
http://www.peachparts.com/shopforum/good-mb-shops/
roy@pelicanparts.com
 
Sam Comments: Excellent write up and guide.

Thank you.
Sam
March 8, 2013
  Followup from the Pelican Staff: Thank you, glad it helped you.
roy@pelicanparts.com
 
sherbet dab Comments: what a brilliant web site, you guys are life savers, will not let anyone touch my merc s320 without them having your info!!
January 23, 2013
  Followup from the Pelican Staff: Thanks for the kind words.

roy@pelicanparts.com
 

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  Applies to: 1992 300SE, 1993 300SE, 1993 300E, 1994 C280, 1995 C280, 1996 C280, 1997 C280, 1995 C36, 1996 C36, 1997 C36, 1994 E320, 1995 E320, 1994 SL320, 1995 SL320, 1996 SL320, 1997 SL320, 1994 S320, 1995 S320, 1996 S320, 1997 S320, 1998 S320, 1999 S320, 1990 300CE, 1991 300CE, 1992 300CE, 1990 300SL, 1991 300SL, 1992 300SL, 1993 300SL
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