In Reply to: New Brakes posted by Philo on May 28, 2002 at 17:54:03:
Rebuilding four piston calipers can be a pleasant dream or a nightmare. It usually depends on how stubborn the pistons choose to be when you try to get them out of their piston bore.
I've had the pistons come out with very little effort so all went well, and I've had them so difficult to remove I swore I would never rebuild another four piston caliper again.
Either way, you do not have to separate the caliper halves so the bolt properties are irrelevant.
As for installing the 540 rear brakes, in my opinion, you would have to be asleep NOT to notice the difference the first time you applied the brakes.
The front of the car does not dip down at all when you brake. Ride with anyone who has installed these brakes and I'm sure you will notice the difference at the first stop sign. I really like this setup on the street.
But I'm still undecided if this is a good thing on the track. While running the full course at VIR earlier this year, an instructor who also owns an e28 M5, immediately commented that the rear of my car felt "squirrely" under hard braking. He also said that I appeared to comfortable with it so we just soldiered on (I was driving.)
Last year at Summit Point, I measured the temperature of the rotors and was surprised to find that the rears were hotter than the front. I have front ducts installed so that may account for the difference - you decide.