Hi there,
If the wheel cylinder is leaking the internal seal is damaged. There are two ways to repair the original cylinder, one is to clean and hone out (if cast as you can't hone alloy) and fit an over size seal, or re sleeve and fit a standard seal, (this you won't be able to do yourself) but the cheapest and quickest option is to fit a new cylinder and re bleed the system.
Mark (mhpautos)
Thursday, July 15th, 2010 AT 7:03 AM