If you look carefully at the inner workings of the brake master cylinder on your Alfa Romeo 1900 & 2600 you will see that it is a rather unusual design. Instead of the hydraulic seal riding in the bore of the cylinder as is typical, on these the sealing surface is actually on the piston not the bore. The piston rides in a ring seal and if the surface of your piston is scored or pitted it will leak pressure. The condition of the bore itself is immaterial except when the cylinder is at rest, as they will dribble fluid out the end past the secondary seal when there is no pressure. You can get your cylinder sleeved to remedy this but you will need a new piston to restore hydraulic pressure. These have previously been unavailable but we have had them specially machined from 6020 aluminum alloy and then hard anodized. The original pistons were steel and subject to corrosion. If your cylinder looks like the one in the last picture (shown for illustration purposes only) and has a 1″ bore then this is for you. We also carry the seal kits for these cylinders. These cylinders also appear on various other vehicles like Aston Martin DB2, DB2/4, and Mark III, Land Rover Series I, Rover 95, 100, 110, P4 & P5, in addition to Jaguar Mk V. There are some special tricks to bleeding these master cylinders which we will include on a sheet with the piston.
Call for pricing 530-241-0600.