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No need to bet - it is a given. I have all the required tools, but no lift. Will attempt to do this myself this week since I will be swapping calipers on my 43 to 63 as well. I've seen hours of YouTube videos and know the process in my sleep now. Will see if I can undo 18mm rear bolts first then torque them back at 60NM/45LBS with 45 degree throw. I will be using additional blue loctite on this 18mm hex bolts (they already have "preinstalled" loctite) just in case I won't be able to do required full 45 degree throw.
Ok I have finished conversion of my GLE43 brakes to GLE63 brakes...for one right rear wheel. This was the plan from the get going - to do only a single wheel per day. In addition to the"usual" procedures for replacing rear pads and rotors as described by Joe in post #1, installing/replacing a new caliper required to transfer parking brake actuator over together with brake sensor harness and opening flexible brake line at the caliper to transfer it to the new caliper, then bleeding the new caliper.
Few observations:
1. Proper tools ARE the most important part of the job (do not save money on ALL proper tools required, do not need expensive brands, but all required tools, sockets, bits, etc. should be acquired prior to starting the job. Followed (very closely) by the know how, which I think I now have after spending hours on YouTube and reading this forum, specifically this thread (thanks Joe once again).
2. 60NM/45LBS plus 45 degree throw is non-issue (at least for me on the right rear side...read on). All was done from the front. No need to go under the car (I would never do it if that was the requirement). Since I'm righty, left rear may be more challenging, we shall see. I was able to use 18" torque wrench in my GLE43's wheel well including to apply 45 degree throw and since GL/GLS's wheel well is (probably) larger, should be possible too.
3. Removing rotor IS (for me) the most difficult, frustrating, time consuming and by far the most tiring part of the job (same bad experience as when I was replacing rotors on the front of my ML63 last month). By far!!! (Did I say that already?) I almost gave up and was ready to put everything back to stock. Am not looking forward to the other three, hence only one per day.
Last edited by threeMBs; Jan 18, 2022 at 07:37 AM.
Why do the rear? Aren't they exactly the same with the exception of the finish? It's the fronts that are totally different.
Even for GL/GLS they are not the same. While all GL/GLS rear rotors are 345mm diameter, only "AMG" 63 rotors are 26mm wide and all others are 22mm. Because of the thicker rear rotors, brake pads carriers are different - the carriers for 63s have 30mm spacing vs. all other only 26mm.
Rear calipers physically look the same, except for "AMG" plate vs "Mercedes" (or no plate at all). I do not know if there are any internal differences (IMO unlikely). I am installing Silver brakes, not Red brakes (have Red on my ML63PP and actually prefer Silver, the fact they are $1,100 less retail just for the color also "helped" in the decision making). So for Silver rear brakes, other than "AMG" plate, calipers and carriers look the same as non AMG rear brakes - "base" finish. I painted rear brake calipers/carriers myself gloss gray. Rotors are obviously different and it is easy to see.
I do not have GL/GLS. Only ML63 and GLE43. Am here because this is where the "action" is and W166/X166 are virtually the same more or less in the brakes area I'm interested in.
So for GLE43, the rear rotors are only 330mm and are not perforated. The difference between the two is night and day. I am not doing the conversions just for the looks. Braking performance of all non AMG63 X166/W166 vehicles is "soft" IMHO. That is what sold me on ML63 more than anything else - I was stunned by its braking power and when bought 43 immediately had buyers remorse and wanted to switch to 63. I was "threatened" with divorce and faced with that possibility/threat kept 43 knowing that one day I will be upgrading to 63's brakes. That time is now. Hence the effort. Actually still have an appointment with dealer to do the install since I bought all parts. No longer going though. Now I know it IS a DIY and I've never done brakes by myself until last month replacing ML63 fronts rotors/pads.
Last edited by threeMBs; Jan 12, 2022 at 09:37 PM.
I tested the rear pads of my GLE 350 with those of the rear pads of the GL63 and they used the same pad. I discovered this since my 350 needed rear pads and I had some extra rear pads from my 63 in the garage. I keep extras since the 63's rear pads need replacement every 10k miles. Those 63 pads slid right in and work perfectly on the 350. The front rotors and pads are completely different and much larger than the 350. Not sure the rears will make a difference with the extra 0.295" of radius over the standard rotors.
They are NOT the same pads. I carefully researched everything related to my swap prior to undertaking it.
While outside dimensions are the same (that is why they fit), the rear 63 pads are just under 17mm thick (including the plate) with GG high performance compound. All other's X166/W166 rear pads are just under 19mm thick (including the plate) with mostly FF (not high performance, but longevity geared) compound (a few are GF "in between" compound). The 2mm less compound thickness combined with high performance compound is the reason rear stock 63 pads yield only 8-10K miles everything else being equal. The factory original rear pads I took off my GLE43 with original 6K miles are FF compound with what looks like zero wear and probably would last 40-50K miles (this is what people with ML350/GLE350 report), they also produced NO dust (never had to clean wheels between washes, not the case with my ML63).
Yes the front calipers/rotors/pads are the ones producing most stopping power and changing from 2 cylinder front caliper to Brembo's 6 cylinder makes a huge difference (along with larger front pads) even though rotor's radius also increases only by the same amount you stated.
Changing 43's rear stock calipers (as I've said above physically and to the eye calipers the are probably all the same, except the finish for the Reds) to 63's is probably mostly cosmetic (could have changed just the "mercedes" to "amg" plate had I known).
However, GG higher performance pads and larger and thicker 345mmx26mm cross drilled rotors vs. solid 330x22 is not only cosmetic but also yield clear performance benefits. Esthetically leaving rear calipers stock was not an option (yes it would be much less expensive just to change the "mercedes" to "amg" plate, but it would not allow me to paint them to closer match the front's color).
The composition of the MB stock pad may be different but I'm using aftermarket ceramics so stock doesn't come into the equation. Again, running rear pads from my 63 on my 350 and they work perfectly.
It's not the thickness of the pads or the compound yielding the 8k to 10k mile wear on the 63; rather, it's the excessive wear is caused by use of the Distronic cruise and lane keep assist. The front pads last 5x longer than the rears and they are of the same composition and do the majority of the stopping so there's that. The right rear pads are always the culprit on both vehicles with the left side and front showing very little wear.
It's not the thickness of the pads or the compound yielding the 8k to 10k mile wear on the 63; rather, it's the excessive wear is caused by use of the Distronic cruise and lane keep assist.
My ML63's rear pads lasted only 16K miles - I am NOT using Distronic ever, I am NOT using Active Lane Keeping Assist ever. Under the same condition rear pads on 350/400 last upto 50K miles. It IS the compound in addition to above mentioned gadgets. Compound is the reason 63's STOCK (I'm talking stock only, forget aftermarket crap pads, would never use anything other than GG compound on 63s) pads wear so quickly and dust so much. My front stock 63 pads lasted also only 16K miles. Your pad mileage does NOT depend on how many miles you drive but on how often you brake and how brakes are used. If you primarily drive on highway with not much aggressive braking, you pads will last much longer. I on the other had really use my pads.
Last edited by threeMBs; Jan 16, 2022 at 04:18 PM.
Reason: Checked my records - 16K miles on both front & rear on STOCK's HIGH performance GG friction pads.
The composition of the MB stock pad may be different but I'm using aftermarket ceramics so stock doesn't come into the equation. Again, running rear pads from my 63 on my 350 and they work perfectly.
It's not the thickness of the pads or the compound yielding the 8k to 10k mile wear on the 63; rather, it's the excessive wear is caused by use of the Distronic cruise and lane keep assist. The front pads last 5x longer than the rears and they are of the same composition and do the majority of the stopping so there's that. The right rear pads are always the culprit on both vehicles with the left side and front showing very little wear.
Probably no coincidence that the wear sensor is on the right side then, eh? MB Service says "Thanks MB Engineering!"
Ok I have finished conversion of my GLE43 brakes to GLE63 brakes...for one right rear wheel. This was the plan from the get going - to do only a single wheel per day. In addition to the"usual" procedures for replacing rear pads and rotors as described by Joe in post #1, installing/replacing a new caliper required to transfer parking brake actuator over together with brake sensor harness and opening flexible brake line at the caliper to transfer it to the new caliper, then bleeding the new caliper.
Few observations:
1. Proper tools ARE the most important part of the job (do not save money on ALL proper tools required, do not need expensive brands, but all required tools, sockets, bits, etc. should be acquired prior to starting the job. Followed (very closely) by the know how, which I think I now have after spending hours on YouTube and reading this forum, specifically this thread (thanks Joe once again).
2. 60NM/45LBS plus 45 degree throw is non-issue (at least for me on the right rear side...read on). All was done from the front. No need to go under the car (I would never do it if that was the requirement). Since I'm righty, left rear may be more challenging, we shall see. I was able to use 18" torque wrench in my GLE43's wheel well including to apply 45 degree throw and since GL/GLS's wheel well is (probably) larger, should be possible too.
3. Removing rotor IS (for me) the most difficult, frustrating, time consuming and by far the most tiring part of the job (same bad experience as when I was replacing rotors on the front of my ML63 last month). By far!!! (Did I say that already?) I almost gave up and was ready to put everything back to stock. Am not looking forward to the other three, hence only one per day.
@threeMBs , congrats on completing the right rear brake conversion on your GLE43. I suspect that you'll find the left side easier now that you have experience with the process.
I'm glad that the 60NM+45 deg. throw for the caliper mounting bracket bolts turned out to be easily manageable. I wonder if my vehicle configuration or my approach to the procedure is somehow different than yours? I get maybe 10-15 degrees of throw before the torque requirement goes up substantially. I am planning to replace these bolts during my next service -- perhaps the new ones will work easier. We'll see. Anyway, good on you for tackling this operation.
Regarding getting the rotors off, I understand your frustration. You have to beat the hell out of them--all the time wondering what kind of damage you're doing to the wheel bearings--and then finally they come loose. I saw in some other thread the idea of using a bolt through the caliper bracket holes to lever the rotor off. If I was having terrible trouble getting the rotor off, I might try this as a last resort. However, I've been having a much easier time since going to the Zimmerman and Brembo coated rotors. Also, I'm in CA so there's not much rust/salt build-up. (I acquired the vehicle from coastal FL and the rotors were almost welded onto the hubs with salt-air corrosion.).
One last point, potentially applicable to rear rotor changes. I think it may be possible (after removing the caliper) to remove the rotor without having to remove the caliper mounting bracket. I want to confirm this during my next service before updating my DIY post. But if it's true, then the whole business with the 45 deg throw is avoided.
Regards, Joe
Last edited by joecparrish; Jan 13, 2022 at 02:17 PM.
@threeMBs , congrats on completing the right rear brake conversion on your GLE43. I suspect that you'll find the left side easier now that you have experience with the process.
I'm glad that the 60NM+45 deg. throw for the caliper mounting bracket bolts turned out to be easily manageable. I wonder if my vehicle configuration or my approach to the procedure is somehow different than yours? I get maybe 10-15 degrees of throw before the torque requirement goes up substantially. I am planning to replace these bolts during my next service -- perhaps the new ones will work easier. We'll see. Anyway, good on you for tackling this operation.
Hi Joe. While the right side was a learning curve as I go, the left side was expected to be a breeze. Not so. First, somehow on the lower 18mm bolt I could not get socket with the wrench on. So to take out lower 18mm bolt had to use long ratcheting wrench after hammering it up a bit. Same issue to tighten it (new bolt, so it was not the bolt but lack of room even though there was more than enough on the right side), but was able to apply most of the torque by hand with some minor hammering down. This is for info only as it did not slow me down. ALL was done from the front. What slowed me down - for a couple of hours or more - was the F(excuse me) rotor.
Originally Posted by joecparrish
Regarding getting the rotors off, I understand your frustration. You have to beat the hell out of them--all the time wondering what kind of damage you're doing to the wheel bearings--and then finally they come loose. I saw in some other thread the idea of using a bolt through the caliper bracket holes to lever the rotor off. If I was having terrible trouble getting the rotor off, I might try this as a last resort. However, I've been having a much easier time since going to the Zimmerman and Brembo coated rotors. Also, I'm in CA so there's not much rust/salt build-up. (I acquired the vehicle from coastal FL and the rotors were almost welded onto the hubs with salt-air corrosion.).
I already gave up (just like I almost gave up yesterday, but was still able to hammer right rear rotor out). The left rear rotor "froze" on the hub. My poor dead blow hammer, it pains me to look at it (it is basically destroyed, like you said above hopefully car is OK as it seems). Thanks to YouTube and after some improvisations, I actually used brake carrier bracket in reveres position to accomplish basically the same idea as highlighted above. I'm in FL and even though car is 95% garaged in air-conditioned garage, the damage was probably already done since car was on dealer's lot for 8 month after production before I bought it.
Originally Posted by joecparrish
One last point, potentially applicable to rear rotor changes. I think it may be possible (after removing the caliper) to remove the rotor without having to remove the caliper mounting bracket. I want to confirm this during my next service before updating my DIY post. But if it's true, then the whole business with the 45 deg throw is avoided.
Regards, Joe
Based on what I observed on GLE43, unfortunately it is not possible because there is not enough room to wiggle the rotor off (this is assuming that it will slide out all by itself).
I still have fronts to do and expect the same tough time removing rotors (already went though with front of ML63 last month, but those were easier than rears of GLE43). Needless to say, this is my very first and very last such conversion that I will undertake myself (after I finish the front). Never had cars long enough to needing to replace rotors (this is voluntary upgrade replacement that I wanted to do for 2.5 years). Changing pads is really easy so if cars are kept long enough requiring new pads, I will change myself, but not the rotors. After I'm done with 43 to 63 conversion, I'm out of the rotors "business". Will let MB dealer do it if needed (I always supply all the parts so this is were most of the money on brakes are saved).
Thanks Joe for your guidance and encouragement!
Last edited by threeMBs; Jan 13, 2022 at 06:31 PM.
I still have fronts to do and expect the same tough time removing rotors (already went though with front of ML63 last month, but those were easier than rears of GLE43). Needless to say, this is my very first and very last such conversion that I will undertake myself (after I finish the front). Never had cars long enough to needing to replace rotors (this is voluntary upgrade replacement that I wanted to do for 2.5 years). Changing pads is really easy so if cars are kept long enough requiring new pads, I will change myself, but not the rotors. After I'm done with 43 to 63 conversion, I'm out of the rotors "business". Will let MB dealer do it if needed (I always supply all the parts so this is were most of the money on brakes are saved).
After finishing the complete job including the fronts, I think the technique of removing rotors by hammering between lug holes widely suggested and shown on YouTube and elsewhere is flawed. After spending significant amount of time and incredible physical effort trying to remove the rear rotors by hammering the middle between the holes to no avail, guiding long (at least 40mm) proper bolt(s) (M12 for the rear and M14 for the front) through support holes from the back to put significant pressure on back part of rotor (even to the point when you can hear an audible "pop") then only one or two blows to the EDGE of the opposite side (where the pressure is applied to from the back) removes the rotors almost immediately (make sure to "support" the rotor with 1 or 2 lug bolts so it does not "fly" or fall off). This is what I have done for the fronts (after doing it for the second rear rotor I could not remove otherwise) and formerly the most difficult and by far the most time consuming part (removing the rotors) became one of the easiest/quickest.
The difficult part for the front, since I was replacing stock GLE43/ML550/GL550 iron calipers with GLE63/GLS63 Brembos, was unscrewing heavy iron (with pads still in them) non-AMG calipers then screwing back on even larger, but thankfully not very heavy Brembo calipers, all with one hand because the other hand has to hold flexible hose stationary all while slippery brake fluid is dripping (yes I did "secure" brake pedal by putting constant pressure on it and while it did help significantly, it did not prevent dripping 100%). Then bleeding each caliper (making mistakes while doing it), then flushing with Motive...am still not content with brake pedal feel so will bleed with "helper" again.
Speaking of torque. Front 80 NM torque plus 45 degree throw must be somehow "translated" to a torque number. I have these front M14 hex 21mm bolts. There are huge and IMO 80 NM is nothing (as comparison, M14 hex 17mm wheel bolts have torque of 150 NM). Joe you stated yourself that torque required to achieve 45 degree throw (after the initial 80 NM) is significant. Why did MB make it so difficult? Couldn't their engineers "compute" the final required torque?
Revisiting this topic. When I was replacing my front calipers (which required removal/install at the steering knuckle) after setting initial torque of M14 21mm hex bolts to 80nm(~60lbs) I then set torque to low 130s lbs thinking that is high enough to achieve 45degree throw. Well when I was at about 45degrees, wrench clicked. Today I actually search mbworld in various ways and it seems to confirm that front M14 21mm hex bolt at the steering knuckle is indeed in the range of 130-135lbs or about 180nm, which is a very high torque, but is appropriate for bolts of this size.
I think/speculate that rear M12 18mm hex bolts, those that MB says to set at 60nm(~45lbs) then continue to achieve 45 degree throw, that final torque is at around 130nm(~96lbs), which logically seems to be appropriate for bolts of this size.
I am puzzled why MB did not furnish the actual final torque numbers for both and instead set this 45 degree throw "standard" after the initial torque.
Please, keep us informed if/when initial bite improves (if any).
If I recall correctly, we are about 1000 miles +/- into these pads and I will weigh in with a major caveat: since this is a feel thing, others perceptions may be very different. I can't say the initial bite has improved, certainly not radically so (although perhaps a side by side drive in a vehicle with fresh pads vs mine may reveal otherwise). Given that we are at least a good bit clear of the break-in, I can confidently say that these are working exactly as I would have expected- noticeably less initial bite than stock, and radically less dust. Braking performance is still what I recall it being when you get into the pedal throw a little, and I haven't noticed any degradation in absolute stopping power when I've had to brake more aggressively. Obviously I haven't tested fade resistance, and don't intend to- if one ever needs to worry about brake fade in normal (or even semi-aggressive) street driving, there's probably a problem outside the braking system (the nut behind the wheel).
Originally Posted by threeMBs
Revisiting this topic. When I was replacing my front calipers (which required removal/install at the steering knuckle) after setting initial torque of M14 21mm hex bolts to 80nm(~60lbs) I then set torque to low 130s lbs thinking that is high enough to achieve 45degree throw. Well when I was at about 45degrees, wrench clicked. Today I actually search mbworld in various ways and it seems to confirm that front M14 21mm hex bolt at the steering knuckle is indeed in the range of 130-135lbs or about 180nm, which is a very high torque, but is appropriate for bolts of this size.
I think/speculate that rear M12 18mm hex bolts, those that MB says to set at 60nm(~45lbs) then continue to achieve 45 degree throw, that final torque is at around 130nm(~96lbs), which logically seems to be appropriate for bolts of this size.
I am puzzled why MB did not furnish the actual final torque numbers for both and instead set this 45 degree throw "standard" after the initial torque.
I'm no mechanical engineer, but I'm wondering if these bolts are torque-to-yield fasteners. In my admittedly very limited experience, these seem to use a torque+throw spec for install. Some light lunch googling leads to this:
Why Do Engines Specify TA or TAY Torque Specifications
With the added benefit of increased clamping force, a smaller fastener can be used when a Torque Plus Angle (TA) or Torque Plus Angle to Yield (TAY)
tightening specification is quantified. For example, an M12 size bolt with a Torque Plus Angle to Yield (TAY) specification can be used in place of an M16 size
bolt with a Torque (T) specification. The use of Torque Plus Angle (TA) and Torque Plus Angle to Yield (TAY) specifications result in a reduction in the vehicle
weight and, therefore, improved fuel economy.
... Given that we are at least a good bit clear of the break-in, I can confidently say that these are working exactly as I would have expected- noticeably less initial bite than stock, and radically less dust.
Though I would love to reduce brake dust (I did not have any brake dust in GLE43 prior to conversion from 43 calipers/rotors/pads to 63 hardware), I fully expected getting the same brake dust after the conversion that I'm getting on ML63. However, I am not willing to give up any initial bite that stock AMG pads provide.
Having said that, I have to say that I am NOT getting the pedal feel in GLE43 with 63 brakes after the conversion (not saying I had it before either, absolutely not) that I am getting in ML63. It is clear to me that going to ceramics will make it even worse. Thank you for your honest assessment.
@2DR Vette also, what year GLS63 did you fit the EBC Redstuff DP32137C on? I purchased these and asked my mechanic to install and he said they didn't fit. I have a 2017 GLS63. Also, I noticed Akebono website shows the EUR1630 pads fit the GLS63 but other sites show they don't. Anyone try these? I have them on my E55 and like them. Thanks
Were you able to find front Akebono pads yet? I can't seem to find them only rear?
Originally Posted by Jbski201
@2DR Vette also, what year GLS63 did you fit the EBC Redstuff DP32137C on? I purchased these and asked my mechanic to install and he said they didn't fit. I have a 2017 GLS63. Also, I noticed Akebono website shows the EUR1630 pads fit the GLS63 but other sites show they don't. Anyone try these? I have them on my E55 and like them. Thanks
NOTE: The Brembo P50101 Rear Brake Pads come with the wrong shims for a 2018 GLS 63 AMG. The MB OEM shims have a 30mm gap for rotors, while the Brembo pad kit includes 20mm shims. The Brembo pads and bolts are correct, but it would be helpful to have a MB part number for the correct 30mm shims.
NOTE: The Brembo P50101 Rear Brake Pads come with the wrong shims for a 2018 GLS 63 AMG. The MB OEM shims have a 30mm gap for rotors, while the Brembo pad kit includes 20mm shims. The Brembo pads and bolts are correct, but it would be helpful to have a MB part number for the correct 30mm shims.
Here's the applicable section from the initial DIY posting (note, I think what you call "shims", I call "springs"):
a. Remove metal springs from caliper support bracket (two places). (Note: If you use the Brembo P50101 brake pad kit, the metal springs provided in the kit are not properly sized for this particular caliper support bracket. Therefore, you’ll need to reuse the existing metal springs. They clean up well with some brake cleaner fluid and a toothbrush.)
FWIW, I don't know if M-B sells the springs/shims individually. I bought a very cheap rear pad set (Raybestos or similar) solely for the purpose of getting a new set of springs/shims in case the existing ones ever wear out. But I've not seen any significant degradation after several re-uses, and I expect that the original springs/shims will last for the life of the vehicle with periodic clean-ups.
Last edited by joecparrish; Jun 23, 2023 at 12:54 PM.
DISCLAIMER
This post is for information only. Your vehicle’s braking system is safety-critical, and therefore requires extra attention and diligence when any maintenance operations are performed upon it. Furthermore, this particular maintenance operation requires the vehicle to be jacked up. If you are not familiar with and comfortable with jacking and stabilizing your vehicle, and with the use of a torque wrench, please do not attempt this operation. You assume all risks associated with working on your own vehicle, and do not hold me liable for any damages. Having this work done by a qualified professional is recommended.
ACKNOWLEDGEMENTS
This post benefits from the good efforts of several MBWorld list members. The format is loosely based on an unrelated post by @Keep; I don’t know if @Keep is the originator of this format, but it is very useful. @cyclrder, @cm60k, @chassis, and @threeMBs have also provided helpful information that is incorporated into this post.
APPLICABLE M-B WORK INSTRUCTIONS (Attached Below)
Move rear axle brakepads into assembly position (AR42.10-P-1700-02W)
17mm “Mercedes Flower Head” lug nut socket (I use an ARES 59012)
17mm thin open-end wrench (I use a Park SCW-17 cone wrench. Other open-end/combination wrenches, such as Snap-On, may be thin enough. Craftsman isn’t.)
Wheel hanger alignment pin M14x1.5 (included with ARES 59012)
Brake caliper piston spreader (I use a DASBET 8542041201)
13mm and 18mm combination wrenches – long 18mm is especially helpful
Needle-nose pliers
Wire brush
Dead-blow hammer
Short bungee cord or wire hanger to hold brake caliper body
Safety glasses
Shop rags and floor protection
OPTIONAL TOOLS
½” impact wrench for wheel lug bolt removal
Angle grinder or drill with wire wheel
Auxiliary lighting
Figure 1: Tools used for this operation
PREPARE THE VEHICLE FOR SERVICE
0. Optional: Raise vehicle to maximum height (Airmatic)
(Note: I need to do this in order to get my Unijack jackstands under the vehicle. Skip this step if you use a shop lift, etc.)
a. With engine running, depress vehicle height button on center console. Multifunction display will show vehicle “raising”.
b. Once “raising” indicator extinguishes, turn off engine.
1. Move rear brake pads into assembly position
(Note: @cyclrder also listed these instructions in his DIY posting. You can use his or use the instructions in AR42.10-P-1700-02W. I include them here to be comprehensive.)
a. Close hood and doors.
b. Release parking brake.
c. With foot off brake pedal, Keyless start push ON -OR- key position 1.
d. Multifunction display must be on the Odometer/Trip display (scroll to this using arrow keys if necessary)
e. On steering wheel, press “accept phone call” button and then (1 sec later) press “OK” button and hold both approximately 5-10 seconds until multifunction display changes to the Workshop menu
f. Scroll using down arrow key to “Brakepad replacement” and confirm with “OK” button.
g. The multifunction dispaly will show “Move to assembly position?” Confirm with “OK” button. Do not depress brake pedal while this operation is underway.
h. Switch off ignition, exit vehicle, and move key to >2m away.
2. Remove brake fluid to allow back-filling into brake fluid reservoir
a. Raise hood.
b. Remove plastic cover above left suspension shock tower. (Note: There are no clips or other features that require special actions. Just lift up on the cover. You may need to move the hood underside rubber seal a bit to allow the cover to come off.)
c. Clean area around brake fluid reservoir cap with a shop rag.
d. Remove cap to brake fluid reservoir and then remove filter ring inside the reservoir neck.
e. Remove brake fluid down to the “MIN” line. Use brake fluid vacuum bulb or siphon line to remove brake fluid into a clean container that can be sealed to keep moisture and contaminants out. (Note: You will add some of this fluid back after the new pads have been installed.)
3. Lift or jack vehicle
(Note: there have been many threads on MBWorld about the challenges of jacking M-B unibody vehicles. For those of us not blessed with a vehicle lift, the challenge is that M-B provides only one single jacking point for each corner, so there is no good way to jack the vehicle and then emplace a jack stand. I use Powerbuilt 620471 Unijack 6000 lb. combination bottle jack/jackstands to address this issue. They fit under the vehicle (barely) when the extensions are removed and the Airmatic suspension is set to its maximum height. Emplace them very carefully to straddle the plastic jacking point. SAFETY POINT: I do not recommend using a floor jack with no jackstand to support the vehicle while you are working on it. Don’t make this mistake — if your floor jack fails, the consequences to your vehicle and possibly your body are SEVERE!)
a. If you don’t have an impact wrench, now is the time to slightly loosen the five wheel lug bolts before jacking. Make sure that you’re using a socket compatible with the 17mm “Mercedes flower head” style bolt heads. If you find that your wheel bolt heads have been marred by previous use of an improper socket, replace with new bolts. The wheel lug bolt part number is A-000-990-54-07.
b. Lift or jack vehicle at left and right rear jacking points until each rear tire clears the floor by at least one inch.
c. Install jackstands or other safety supports for raised vehicle.
4. Remove wheel (BOTH SIDES)
(Note: it might seem like the alignment pin is optional, but the larger wheels on the GLS 63 are quite heavy and awkward to maneuver. Furthermore, the use of bolts (vs. studs) means that the wheel will tend to fall off when the final bolt is removed. I don’t think this job can be done solo without using the alignment pin.)
a. At top bolt location, remove wheel lug bolt and screw in the M14x1.5 wheel alignment pin.
b. Remove remaining four wheel lug bolts.
c. Slide wheel off.
d. Remove wheel alignment pin
Figure 2: Right rear hub, disc rotor, and caliper -- ready for service!
DISASSEMBLY INSTRUCTIONS
5. Remove brake pad wear sensor (RIGHT SIDE ONLY)
a. Disconnect wear sensor connector body by pulling it outboard from the sensor receptacle. Use needle-nose pliers to grasp the connector body if your fingers don’t fit in the tight space.
Figure 3: Brake wear sensor connector and receptacle
b. Note: the M-B work instruction AR42.10-P-0080W here directs the removal of the sensor receptacle from the brake caliper body. I don’t think this is necessary, if you simply loosen the sensor receptacle wire to give more play. See instruction item c below.
c. Disconnect wear sensor receptacle wire from restraints in two places (see photo below). Removing the wire from the little trough (top) is straightforward. Removing the wire grommet (bottom) is a bit trickier – be careful not to break the plastic clip. Gently apply pressure to both sides of the grommet in an inboard direction until it pops out.
6. Remove brake caliper body (BOTH SIDES)
a. Release and disconnect electric parking brake actuator connector. (Note: There is a little tab, somewhat like that on a RJ11 or RJ45 jack, on the underside that must be depressed in order to free the connector. Use a little screwdriver to depress the tab if your fingers are too big.)
Figure 5: Electric parking brake actuator connector and receptacle. The release tab is hidden beneath the connector (left) in this photo.
b. Using a 13mm socket, remove the caliper bolts from the caliper guide pins (two places). Once you’ve cracked the bolt loose, you’ll need to insert a thin 17mm open end wrench to keep the guide pin boot from rotating (and possibly tearing) while you complete the removal of the caliper bolt.
Figure 6: Use a thin 17 mm open-end wrench to keep the caliper pin boot from turning
c. Remove brake caliper from caliper support bracket. Support caliper in one hand while you remove the used brake pads from the caliper body or caliper support bracket.
d. Using a short bungee cord or wire hanger, support the caliper body so that it doesn’t hang from the brake line (and/or brake wear sensor receptacle wire on right side)
Figure 7: Use a shorter bungee cord than this one if possible
e. Press brake piston into caliper body using piston spreader tool. Piston should retract almost flush with the caliper body.
7. Remove brake caliper support bracket (BOTH SIDES)
a. Remove metal springs from caliper support bracket (two places).
(Note: If you use the Brembo P50101 brake pad kit, the metal springs provided in the kit are not properly sized for this particular caliper support bracket. Therefore, you’ll need to reuse the existing metal springs. They clean up well with some brake cleaner fluid and a toothbrush.)
b. Using a 18mm wrench, remove the caliper support bracket bolts from the caliper support bracket (two places). (Note: These bolts are installed with high torque, so it will take quite a bit of force to crack the bolt loose. I used a long 18 mm combination wrench and a dead blow hammer to crack the bolt loose. Once cracked loose, the bolt unscrews easily by hand.)
c. Remove caliper support bracket from rear suspension wheel carrier.
Figure 8: Brake caliper support bracket and bolts
d. Clean up the caliper support bracket, steel springs, and caliper support bracket bolts using brake parts cleaner fluid.
8. Remove brake rotor (BOTH SIDES)
a. Using a T30 bit, remove the brake rotor set screw.
b. Remove the brake rotor from the wheel hub.
(Note: It is likely that the rotor hat will be stuck on the wheel hub, requiring some serious hammering on the disc with the dead blow hammer in order to free the rotor from the hub. This problem will be worse in wet or cold environments if rust/salt is able to build up. I really hate hammering on the disc, as I think it cannot be good for the wheel bearings. If anyone knows of a gentler way to lever the rotor off of the wheel hub, please let me know.)
c. Clean up any accumulated rust or salt buildup from the wheel hub using a wire brush. A toothbrush-style brush works fine, but a brush mounted on a drill or angle grinder turns this chore into a fun task. Don’t forget eye protection.
REASSEMBLY INSTRUCTIONS
Note: Generally speaking, reassembly is the inverse of assembly, so I’ll not repeat those instructions in such high level of detail. I will call out torque values and any aspects that are unique to reassembly.
9. Install brake rotor (BOTH SIDES)
a. Place the brake rotor (A-166-423-05-12 (or Brembo 09.8710.11-3 or Zimmerman 400.3699.20)) on the wheel hub, being careful to align the set screw hole on the rotor with the threaded hole in the wheel hub.
b. Install the brake rotor set screw (A-220-421-01-71 (or Febi-Bilstein 21663)) using a T30 bit, torque to 10 Nm.
(Note: I don’t think this torque setting is important. All the set screw does is hold the rotor on the wheel hub until the wheel is installed. Instead, I use the famous TFAR (That Feels About Right) method to install this screw without bothering with a torque wrench. Be careful that you don’t cross-thread or strip the threads in the wheel hub.)
10. Install brake caliper support bracket and brake pads (BOTH SIDES)
a.Inspect the caliper guide pins and boots (two places) for smooth action and/or leakage of grease from under the boots.
(Note: If the caliper pins do not operate smoothly, lubricate or replace them. It’s important for the anti-lock braking system and also the active lane-control system that the brake pads slide smoothly on the caliper pins.)
b. Install the metal springs on the caliper support bracket (two places).
c. Install the caliper support bracket to the rear suspension wheel carrier using the caliper support bracket bolts (two places) using a 18mm wrench, torque to 60 Nm then 45° angular throw.
(Note: This is the least pleasant task in this entire operation, IMHO. I am not able to get enough leverage using muscle power alone to make that 45° throw, even if I use an extra-long 18mm combination wrench. The tight quarters prevent the use of a breaker bar and socket. I need to use a dead-blow hammer to get the 45° throw, and I suspect the work instructions assume that this operation is done with smoothly-applied leverage only. If anyone has a better solution to this issue, I’d love to hear it.)
d. Install new brake pads (A-007-420-86-20 (or Brembo P50101)) with the pad ears riding on the metal springs. Note that the pad with the receptacle for the wear sensor goes on the inboard (I.e., caliper piston) side.
(Note: I know that most brake pad installations recommend the use of anti-squeal paste on the pad ears and backing plate. The M-B work instructions AR42.10-P-0080W and AR42.10-P-1700W specifically say not to use brake paste or lubricants. Before I acquired the vehicle, several brake services had been performed at a M-B dealership, and I found no evidence of any paste or lubricant ever being used on these surfaces. Therefore, I don’t use any paste or lube in this procedure.)
11. Install brake caliper body (BOTH SIDES)
a. Remove the brake caliper body from bungee cord or wire hangar support and slide it into place over the brake pads. (Note: Some wiggling may be required if the pads are thick or the caliper piston hasn’t been retracted all the way into the caliper body.
b. Install the caliper bolts (A-019-990-64-01; included in many brake pad kits, yes for Brembo) through the caliper support bracket (two places) using a 13mm wrench, torque to 35 Nm. Don’t forget to use the 17mm thin wrench to keep the guide pin boots from rotating during the bolt installation.
c. Reconnect the electric parking brake actuator wire connector.
d. Reinstall the brake wear sensor receptacle wire in its restraints (two places: one trough, one grommet clip).
12. Install brake wear sensor (RIGHT SIDE ONLY)
a. Insert the brake wear sensor (A-211-540-17-17 (or Bowa A1680003)) into the inboard brake pad. There’s a little hole in the pad to receive the probe-like protrusion on the wear sensor. The wires for the sensor should point in the outboard direction. See photo below.
Figure 9: Brake wear sensor installed on right inboard brake pad. Next step is attaching the wear sensor connector to receptacle
b. Insert the brake wear sensor connector into the receptacle. It should bottom out with a slight click. Refer to Figure 3 to see how the installed connector looks when it’s bottomed out correctly.
14. Reinstall brake fluid reservoir filter ring, refill brake fluid to MAX line on brake fluid reservoir, reinstall brake fluid reservoir cap, reinstall plastic cover over left suspension shock tower, close hood.
15. Retrieve key, enter driver’s seat while keeping foot off brake, close driver’s door, key to position 1, follow instructions on multifunction display to exit from brake pad assembly position.
16. Test drive the vehicle, and perform any pad bedding-in procedure per recommendation of the brake pad manufacturer.
17. Once the vehicle is parked, crack open a cold beverage -- secure in the knowledge that you’ve gained experience about how your vehicle works and you’ve also saved a bundle in labor charges and often-inflated parts prices!
I would greatly appreciate corrections or suggestions to improve this article. Regards, Joe
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