joecparrish

Folks, I had posed this question inside a longer message in the great thread on DIY brake rotor/pad replacement initiated by @cyclridr. I’m hoping that someone with detailed part diagram access can assist. The assembly in question is the AMG front brake caliper; my vehicle is a 2017 GLS 63, but I think this caliper is used widely across the years of the AMG X166 vehicles.

The MB maintenance procedure (AR42.10-P-0070GZ Remove/install front axle brake caliper; step 6.2) calls for replacement of the front axle brake caliper body to steering knuckle bolts whenever the caliper body is removed — as happens when replacing a rotor. (Same for the rears, but those replacement bolts are usually included in most brake pad kits. Not so for the front.)

The bolts in question are M12 (I think) socket head cap screws, approximately three inches in length and they come with a separate small-diameter flat washer under the head. They appear to be steel, with some kind of treatment that leaves them a dull silver color. I don’t know if this treatment is for hardening or corrosion resistance. They have thread locking paint applied. You can see the head of one of the two screws per caliper in the photo below — is at the lower left and looks like half black/half silver due to some dirt or old black paint. (The second bolt is just cut off in this shot.)





If anyone knows the part number for these bolts, I’d appreciate the reference. I’ve had no luck searching MB online parts houses, as these particular bolts are not called out as separate items on the assembly diagrams.

reddog

On my 2018 GLS63 the part numbers for the" front brake caliper to steering knuckle," both left and right are as follows:
Bolt with flange: A 019.990.56.01 Quanity: 2 per caliper.
As your model is a 2017 model the parts may be different.

Reddog.

The dimensions of the bolts: M14 x 1:5 x 40

cm60k

I think you mean this (M12X72mm) allen key bolt, isn't..??




-;-ZAYED-;-

joecparrish

Thanks @reddog, but these 019.990.56.01 bolts are not the correct ones for the AMG (Brembo rebadge) calipers. I think (guess) that they are appropriate for the “standard” (non-AMG) front calipers on the non-AMG GLS vehicles.

FWIW, I have four of these bolts that I purchased in anticipation of using them on this job; then I was presented with the other style (SHCS) when I pulled the front wheel and gained access. PM me if you wish to purchase them at a discount.

joecparrish

@cm60k , yes! These M12X72mm allen key bolts are the correct bolts. Do you happen to have a part number or online source for them? I want to be sure to get the correct hardening/surface treatment.

Thanks, Joe

cm60k

They are always available are any local dealer, or can even order them online,,

the MB part #: (A003 990 79 05)

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cm60k

A) https://www.fcpeuro.com/products/mer...mer-0039907905

B) https://www.ebay.com/itm/Mercedes-Be...-/174239084053

C) https://www.mbonlineparts.com/oem-pa...olt-0039907905

D) https://www.ecstuning.com/b-genuine-...ca/0039907905/

-;-ZAYED-;-

reddog

Hi Joe,
Thanks for the reply. My 2018 GLS63 is the "AMG" model. Perhaps the bolts WERE changed in 2018 on the AMG model.
My VIN is; 4JGDF7FE8JB051873.


REDDOG

joecparrish

So, @cm60k and @reddog, it turns out that both of you are correct, and I am the one who was wrong! Let me elaborate...

I think there are three major items being connected: (1) caliper body, (2) caliper mounting bracket, and (3) steering knuckle. I now believe that 0199905601 (M14x40, 21mm hex head bolt) are the bolts (qty:2) that connect the caliper mounting bracket to the steering knuckle. It’s item #35 in the diagram below, taken from the M-B work instruction. 0039907905 (M12x1.5x72, 10mm hex Socket Head Cap Screw) are the bolts (qty:2) that connect the caliper body to the caliper mounting bracket. This particular bolt isn’t called out by number in the diagram, but it’s just to the left of the callout text box that says “S10/2x1”. (I wonder if this text block is in fact saying that the adjacent bolt is a S10 - socket head 10mm, or is this just a coincidence?)

M-B wants you to remove the two 0199905601 caliper mounting bracket-to-steering knuckle bolts when you remove the caliper body, and I failed to follow the instructions carefully and instead removed the two 0039907905 caliper body-to-caliper mounting bracket bolts. Either way results in the caliper body coming free and provides access to the rotor. That’s my error, and it led me to believe that somehow the 0039907905 bolt had supplanted the 0199905601 bolt. That’s not true — both bolt types are present in all of our AMG GL’s! I hope this explanation makes sense, and I feel a bit sheepish to have fixated on the 0039907905 bolt.

All that being said, I’m not exactly sure why M-B wants you to use the 0199905601 bolts instead of the 0039907905 bolts for the caliper removal procedure. The 0039907905 bolts are much easier to access, and they put your breaker bar and/or torque wrench handle in a much more accessible orientation to deliver high torque. I dealt with the functional equivalents of the 0199905601 bolts when I did the rear brakes, and it was probably the hardest part of the entire job to do that particular bolt-torquing operation.

Thanks again for the assistance. I hope my ramblings will be helpful to others.

Regards, Joe

cm60k

No Joe,

You can remove the calipers by removing those (M12) allen head bolts for sure, i'm always doing that..!!,,

of course no need to touch those (M14) spindle hex bolts,

Brembo made those separated brackets, to make it more easy for removal,

just need to be careful, when you remove those (M12) allen bolts, don't remove one bolt & keep the other, cause the bolt is (12mm), and the hole is (12.7mm)..!,

only (0.7mm) gab, means bolts are more pressed..

-;-ZAYED-;-

joecparrish

Zayed—

Could you please explain what you mean here? I’m not sure I understand your point. Thanks.

BTW, do you know the torque requirement for the M12 socket head cap screws? Of course the M-B procedure calls out the torque value for the M14 hex head bolts (80 N-m + 45 degrees). I don’t want to assume the torque settings are the same for these different-sized bolts.

Regards

—Joe

cm60k

No worries Joe,

Those bolts are not full threaded,

simply, you can remove upper bolt by 2 or 3 threads, to release the pressure, then remove the lower one,,

the torque for this (M12) bolt is (80 ft-lbs) >> (110Nm)..

-;-ZAYED-;-

joecparrish

Thanks, Zayed. Now I understand your point. I don’t think I've ever seen it written down as a rule, but I think that “loosen all bolts first, then remove individual bolts” is good technique for any multiple-fastener application. It is tempting — especially when using an impact wrench — to just keeping going and extract individual bolts completely. As you note, this can result in binding and misalignment problems downstream.

And thanks also for the torque setting.

—Joe

cm60k

Yeah, that's Exactly what i meant Joe.,

you Explain it so professionally..,,

and sorry, my English blows occasionally..

-;-ZAYED-;-

threeMBs

Great info. Thanks Joe and cm60K.

threeMBs

cm60k, do not what to come across disrespectful, but is there a source supporting setting torque to 110NM for these M12 caliper bolts?

kenneyd - https://mbworld.org/forums/w212-amg/...nt-brakes.html - about seven minutes into his video stated that torque is 120NM. Yes his is W212 AMG, but bolts are identical and I'm sure the caliper bracket as well. Hardware is hardware (all MB "long" M14x1.5 45mm wheel bolts regardless of the model is to be set to 150NM, while all "short" M14x1.5 27mm wheel bolts - 130NM).

I just finished doing my left side today and set M12 caliper bolts to 110NM, but now have started having doubts if I should have done 120NM instead. I would appreciate further clarification if possible.

EDIT: today when working on my right side, I removed M12 bolts by setting torque ranch to about 114nm. The bolts were removed, which means if torque from the factory was set to 120nm, it would not have removed the bolts. So 110nm it is (which is just over 81ft lbs, but I actually set to 82 ft lbs). Thanks.

EDIT #2: it appears torque is at 120NM / 88LBS (so range is 110nm-120nm or 81lbs-88lbs) :
https://mbworld.org/forums/coupe-roa...cs-please.html

JJWON

Hi,
I want to know the Brake Caliper bolt Part# for the 2014 E63AMG S ( Brembo brake).
I tried to do DIY brake job but both bolts ( upper & lower ) were broken.

I appreciate it.