The brake master cylinder for the 1969 US spec Alfas has gotten more difficult to rebuild as parts are no longer being made by Ate, the original manufacturer.  I did quite a bit of research to try and locate new seals and a boot.  Alfa Stop, in the UK, has a kit that contains the seals and a boot.  This kit is being manufactured in the UK and is the same kit used by White Post Restorations.  I wasn't very impressed with it.  The seals are very hard and the boot is so hard that it doesn't stretch very much.  Going on the assumption that Ate used the same seals in most of the cylinders, I searched on Ebay for rebuild kits for 22mm Ate cylinders.  I discovered that all of the 22mm Ate cylinders use the same primary and separating seals.  The secondary seal differs for some cylinders.  The cylinder found on the 69 Alfas, has a different secondary seal on the rear-most piston.  I found a rebuild kit for a late sixties Volkswagen Van and discovered that it had the same seals that were needed to rebuild my cylinder.  The only thing that was missing was the boot.  A little more research revealed that the boot from the 22mm kit for the Giulia with power brakes would fit.  I also found the piston seal would work as the secondary seal for the rear-most piston.  To rebuild the master cylinder, two seal kits are required, one from the Alfetta and the other from the Giulia with power brakes.  International Auto usually stocks these kits, 3822 and 4822.

The next hurtle was to look into having the cylinder sleeved.  I learned there are two schools of thought about sleeving, brass and stainless steel..  White Post Restorations seems to be the most popular place to send cylinders out for sleeving.  White Post uses a brass sleeve to restore cylinders.  Brass is really not a good substance to use as it is very soft and won't hone.  The honing process puts a cross -hatched pattern in the cylinder.  This cross-hatch is critical to lubricating the seals inside the unit.  Also, since the pistons tend to chatter across the surface of the cylinder, the brass will wear and develop a rippled surface.  All of this can lead to premature brake failure.  The folks at Karp's Brake Service feel that a stainless steel sleeve is far superior to a brass sleeve.  Stainless steel can be honed and does not get worn like brass.  Karp's uses the Hal-Ray method of sleeving cylinders.  The Hal-Ray method uses 304 drawn stainless steel tubing.  The cylinder is bored and receives a stainless steel tube.  A high tech cement is squeezed around the sleeve to create a permanent bond.  Then, all of the ports are drilled and the unit is pressure tested.  After a nice long talk with the owner, Ron Karp, I decided to send my cylinder to him for sleeving.  Now that I had everything figured out, it was time to disassemble the master cylinder and send it out for sleeving.

As luck would have it, the cylinder was a bit of a challenge to Karp's.  It was the fist time they had seen one of these.  They were concerned about two aluminum plugs that lie on the top of the cylinder.  Both had to be removed in order to properly service the cylinder.  They discovered that the forward most plug was not thin like the rear plug.  It was quite long.  A quick check with Ate, produced a beautiful cross sectional schematic of the cylinder.

This schematic revealed everything and a new plug was fabricated for the cylinder.  The rear plug was reused and sealed with the same bonding agent use to secure the sleeve.  The front plug was held in place with a 1/4" pipe thread plug.

Sleeved master cylinder.  Note the small plug between the two front ports

Closeup of front plug

Closeup of rear plug

Closeup of cylinder bore.  The sleeve can easily be seen in the photo.  The dark material
around the sleeve is the bonding agent the keeps the sleeve in place.

Disassembly

Start by clamping the cylinder in a vise so that it is oriented with the boot pointing up.  Remove the retaining clip from around the large end of the boot.  Remove the boot from the cylinder and fold it over on itself.  Lift the bottom of the spring up and remove the spacer.  It may make things easier to compress the spring and clamp a pair of long nose vice grips around the actuator rod to keep the spring up and out of the way.  Remove the circlip and pull the actuator rod way from the cylinder.

To remove the rear piston, put an air nozzle to one of the rear ports and apply short bursts of compressed air.  Care should be taken as the piston could shoot out and hurt someone or something.  Use a shop rag in the palm of your hand to cushion the piston and keep it from flying out.  I prefer to turn the cylinder upside down so that the piston comes out and hits the top of the workbench.

Remove the 3mm bolt from the underside of the cylinder.  This bolt holds the front piston in place.  Compressed air will probably be required to pop out the second piston.

Lay out the components in the order they were removed and photograph or make a sketch of them and their orientation to each other.

Pay particular attention to the piston seals.  There are three different kinds, two of which look identical.  Close examination of the pistons will show that they both have the same primary seals (the ones at the front) but have different seals on the rear.  The front piston has separating seals and the rear piston has what is called a secondary seal.

The picture above is of the front piston.  Note the concentric groves in the two rear seals.  These are separating seals. Primary seals do not have the concentric groves.

Note the different style secondary on the rear piston.  This seal seems to be unique to master cylinders with actuator arms.

Cleaning

All of the parts should be cleaned using brake cleaner.  It's also a good time to inspect all of the components to make sure that they are reusable.  The pistons will show some evidence of wear.  The pistons can wear to the point that the are not useable, but this is usually pretty rare.  Serviceable pistons will have a clearance with the cylinder wall that is no more than 0.26 mm.  The diameter of the piston, when new is 22.05 mm.

Assembly

It is recommended that a thick coat of paint be applied to the outside of the cylinder.  This will help protect it against corrosion, so some degree.

It is essential to work in a very clean area.  Any dirt that is introduced into the cylinder can cause premature brake failure.  Most people use brake fluid to assemble the cylinder.  It's ok to use brake fluid, if the cylinder is going right back in the car and the system filled with fluid.  Otherwise, use brake assembly lube.  Spread lubricant on the pistons and seals.  Install each of the seals; take care not to stretch them too much.

Apply a sufficient quantity of lubricant to the inside of the cylinder and the pistons.  Place the spring on the piston and hold the piston such that the spring is pointing up.  Turn the cylinder so that the opening is down and offer the piston and spring to the cylinder.  Push the piston into the cylinder until the spring can be felt to stop.  Insert the 3mm bolt, but do not try to screw it all of the way in.

Turn the cylinder so that the open end is up and insert a long blunt instrument to push the piston into it's proper place.  Hold the piston in place and tighten the 3mm bolt.  The tip of the bolt should be visible in the cylinder.

Install the second piston.  It may require a gentle pop to get the seal seated in the cylinder.

Use a pair of vice grips as pictured above to hold the actuator return spring away from the base.  Offer the actuator rod to the cylinder and insert the circlip.

Make sure the circlip is properly seated in the cylinder.  A new circlip is provided in the Alfetta brake master cylinder rebuild kits.  Use that instead of the old circlip.

Install the spacer and remove the vice grips from the actuator rod.  Install the boot and the retaining clips.