Audi A8 2003 Workshop Manual page 104

Audi A8 2003 ➤
Brake system - Edition 03.2013
♦ Lithium grease - G 052 150 A2-
Removing
– Force pistons out of brake caliper housing one at a time using
compressed air.
The pistons can only be removed one at a time. Hold the opposite
piston in the caliper housing with piston resetting appliance -a-.
Use blocks of wood or similar -b- to keep the other pistons in
place. Also place a piece of wood -c- against the resetting tool to
prevent the piston from being damaged when it is forced out.
– Remove seal using removal wedge - 3409- .
When removing ensure that the bore of the cylinder is not dam‐
aged.
Installing
WARNING
The brake pistons have different diameters. When re-installing,
please make sure that each of the brake pistons is inserted in
the correct aperture in the brake caliper. The ceramic inserts
on the brake piston act as heat insulators and must not be
separated from the brake piston. If the ceramic insert is dam‐
aged, the brake pistons must be renewed for safety reasons.
– The surface of the piston and seal should be cleaned using
only methylated spirits and then dried.
– Apply a thin coat of lithium grease - G 052 150 A2- to piston
and seal before inserting.
– Insert the seal into the brake caliper housing.
98
Rep. gr.47 - Brakes - hydraulics
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