# Master cylinder, rebuild

Dismantle master cylinder by pulling off rubber boot and removing circlip located in top of cylinder. Slide out piston assembly and spring. Remove the seal ring from the inlet and clean the housing thoroughly..

Replace master cylinder if there is any corrosion or scoring of the cylinder.

A rebuild kit should contain a new piston assembly, circlip, protective cap, sealing plug and spring.

Coat the cylinder bore with ATE brake cylinder paste or an equivalent before assembly.

E30 M3 Repair Manual V2.7. Copyright ©1999-2001 Koala Motorsport & Brett Anderson