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Discussion Starter #1
Searched, and a couple of questions on the Gen II front brake upgrade on my 1984 500SEC with 15" 560 wheels.
I am a street driver who needs new callipers and rotors, so this is a good time to upgrade.
Is the Gen II swap currently the biggest bang for the buck option? - Uber expensive aftermarket kits are not affordable for me, nor warranted in my application.

Several posts suggest that this is a simple bolt on mod, but do not mention ABS cars. Does ABS complicate the issue both with fitment and ABS operation?
I see one post stating that is is not a simple bolt on and that new ABS sensors are required?
1265464243 ABS Cable Bracket at Wheel Housing Genuine $1.69 x 2
1265402517 ABS Speed/Wheel Sensor; Front Left Bosch OEM $137.72
1265402617 ABS Speed/Wheel Sensor; Front Right $137.72


Does the ABS system operate the front brakes independently of the rears, and will it cope with greater braking force on the fronts?
Is there a proportioning valve in the system, and if so how does it cope with the bigger fronts?

If I understand correctly, my stock MC will suffice for either the dual or 4 piston Gen II callipers, but when time for a MC buy a Gen II

Several posters suggest that there is little, if any, benefit with 4 piston SEL callipers over 2 piston?
 

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Discussion Starter #2
I now see that Pelican lists different PN for the Gen I and Gen II master cylinders. Is this a hydraulic issue that will affect the operation or related to the different reservoir?
 

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CH4S Admin , Outstanding Contributor
1985 500SEC, 1991 190E 2.6.
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My old MB mechanic Jerry RIP, did the swap on my Gen I 500SEC, I know we have the 560 calipers and a bit larger front rotors, but I forgot whether he installed complete with spindle. ABS was maintained without changing the master cylinder, if I remember correctly.
I am sure one of the resident experts will chime in. Otherwise, click the 3 dots top right next to your avatar, and advanced search restricted to W126, or just google 'Mercedes W126 Gen I brake upgrade.'

One of the members here invested about $10 k just for brakes in his SEC. For the kind of rotors used, he had to go to 18" wheels.
 

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Discussion Starter #4 (Edited)
Thanks for the search hint - that would have saved a lot of reading yesterday, but the good part is that now I am more informed.
Nothing I could see about ABS other than the post I cribbed above.

Nothing about a proportioning valve either but as no one has mentioned fore-aft balance after the larger Gen II rotors and callipers on the front, perhaps it is a non-issue? Or maybe the ABS is masking any potential balance issue?

The MC is a different PN from Gen I and II but I do not know if it a bore/stroke difference, or a mechanical difference
 

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I have a Gen I grey market 500SEC. In April I replaced the brake pads and man oh man the brake dust is horrid. When it's time for new pads and rotors I am thinking I should go larger, with ceramic pads. Brake dust and BBS wheels do not mix.
 

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Discussion Starter #6 (Edited)
I know we have the 560 calipers and a bit larger front rotors, but I forgot whether he installed complete with spindle. ABS was maintained without changing the master cylinder, if I remember correctly.
The Gen II swap is well documented here and appears to be a simple bolt on of the Gen II callipers and rotors to the existing spindle and hoses. The only complication appears to be ABS sensor fitment, and my OP denotes the parts needed.
Did you have to procure these new ABS parts?

The MC is a simple pump, and a different PN in the two Gen's. Unless the difference lies in bore/stroke, the ABS operation should be unaffected. An answer to the hydraulic differences would be helpful.

ABS operation is my question, as with larger fronts and the same rears, the fore-aft balance will be affected. I also do not know if there is a proportioning valve to adjust balance, and if so this needs to be factored in.
 

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So that’s what the three dots are for. Enlightenment.
 
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