Welcome to the fest!
Not preloading the bearing will result in just what you had happen. The previous one probably cracked because it was old and worn out. The crack was a result of the loose motion from wear, and that transferred to the mount.
Did you keep the front driveshaft in register with the rear when you replaced the CSB? They are balanced as a unit, and if you get it turned so that the two parts don't align the same as when they were made, you get vibration and premature CSB wear.
Quotes to live by:
guessing gets expensive...drivinfaster
nothing is more expensive than a cheap BMW...c4harpe13
buying a ratty example (of a BMW) is a parasitic relationship.(and you ain't the mosquito) 7pilot
Ken Kanne, Silverhill, AL, E36 & New Member Intro Forum Mod/Bimmerfest Misplaced-Posting Tow Truck
BMW-CCA #441426 My E30 makes me do stupid things.
1995 318is "Bebe"; 1993 325is "Elvira"; 1985 635CSi "Katja"; 1984 633CSi "Sylvia"; 1987 325is "Odette"