Front Brake Caliper Piston, FNRG57

Special tools and workshop equipment required

Removing

-- Force piston from brake caliper housing using compressed air.

Fig 1: Removing Protective Cap From Brake Caliper With Trim Removal Wedge 3409

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Place a wooden board into the recess of the caliper housing so it is not damaged.

-- Remove seal.

Fig 2: Removing Seal With Trim Removal Wedge 3409

Courtesy of AUDI OF AMERICA, LLC

-- Use the 3409 for this.

NOTE:

When removing, make sure that surface of cylinder is not damaged.

Installing

-- The surface of the piston and seal must only be cleaned with mineral spirits and then dried.

-- Thinly coat piston and seal with lithium grease G 052 150 A2 before inserting.

-- Using 3409, insert the inner seal into the groove in the brake caliper.

Fig 3: Identifying Sealing Ring Installed In Brake Caliper

Courtesy of AUDI OF AMERICA, LLC

-- Press in the protective cap using special tool -1- and -2-.

Fig 4: Identifying Protective Cap Pressed Into Brake Caliper With Assembly Tool And Piston Resetting Tool

Courtesy of AUDI OF AMERICA, LLC

-- -1- T10146/2

-- -2- T10145

Use protective backings

-- Press the protective cap onto the brake caliper housing so that it contacts the brake caliper housing all around -arrow-.

Fig 5: Pressing Protective Cap Onto Brake Caliper Housing So That It Contacts Brake Caliper Housing All Around

Courtesy of AUDI OF AMERICA, LLC

-- It should no longer be possible to remove the protective cap from the brake caliper housing by hand.

-- Thinly coat piston and seal with lithium grease G 052 150 A2 before inserting.

-- Lift the brake piston, as shown, with commercially available extension and ratchet adapter and lightly press against the protective cap.

Fig 6: Identifying Piston Pressed Against Protective Cap With An Extension And Ratchet Adapter

Courtesy of AUDI OF AMERICA, LLC

Do not angle piston, to avoid damaging the seal sleeve.

-- Blow the protective cap on with pressurized air (max. 3 bar). The protective cap will thereby jump over the brake piston.

Use protective backings

-- Press piston into the brake caliper housing by hand.

NOTE:

The inner sealing lip of the protective cap thereby slips into the groove on the piston.