I`ve only driven a couple of s13`s and TBH I didn`t have a problem with the ABS systems. Both of them worked perfectly (in the wet).

I`ve checked the 2 servos side by side, the s12 servo is slightly larger in diameter, but the s13 one is deeper. The s13 servo fits into the bulkhead perfectly, but the s13 MC is a bit closer to the suspension turret than the silvia one. Plus the rod (that connects to the brake pedal) is a bit shorter on the s13. But I guess this can be altered on the adjuster to take up the difference.

I`ve not checked to see if the s13 MC will fit onto the s12 servo. But if anyone is thinking of this mod, it`s probably best to use the complete s13 servo and MC complete :D .

Regards,
Ian.

Don't see the need to use the servo.

Just use the master cylinder, it bolts on

I agree, you don't need the servo for the ABS so no need to swap.

Guess that tells me......LOL... :p .

But I guess it`s good to know that the s13 servo fits into the same bulkhead mounting, just in case someone is struggling to get hold off a s12 one ;) .

Regards,
Ian.

It's always good to know that there's something that will "just bolt on" :D

pedal sinks to the floor and doesn't recover easily if ABS engages. ABS ecu gets confused if you spin (on track for example) and gives you zero braking going backwards, and most of all it totally kills the pedal feel. The best thing I've ever done to s13 brakes is remove the ABS. I'd do it before changing calipers now.