Vehicles before change point in 1982
OVERHAULING TANDEM BRAKE MASTER CYLINDER
Important: Use repair kit.
Remove and install tandem master cylinder -
34 31 000.
Apply light pressure to piston (1). Unscrew
stop screw (7). Lift off circlip (2) and pull out
piston (1). Scrape off stop washer (3),
secondary cups (5), intermediate ring (4)
and bearing ring (6).
Installation: Apply light pressure to piston
(1) when installing stop screw (7). Replace
copper seal underneath stop screw. Coat
piston skirt with silicone grease.


34 31 000

Installation: Install secondary cups (5) to
point in one direction.
Coat space between secondary cups (5) and
intermediate ring (4) with a silicone grease.

Unscrew connecting screw (9) to replace
primary cup (8).
Pull of spring retainer (10), spring (11),
support ring (12), primary cup (8) and
filler disc (13).
Installation: Make sure that support ring (12)
fits properly on primary cup (8).

Remove intermediate piston (14) by knocking
housing against a wooden base slightly.
Pull off spring (15), support ring (16), primary
cup (17) and filler disc (18).
Remove separating cups (19).
Installation: Separating cups (19) in a repair
kit are marked with a colored ring. Install
separating cups (19) that both sealing lips face
in opposite directions.
Make sure that support ring (16) fits properly
on primary cup (17).

Clean all parts with spirits of wine.
Tandem brake master cylinders having surface
damage in cylinder bore may not be reinstalled.
Install new parts with a very thin coat
of ATE cylinder paste. Clamp tandem master
cylinder in a vise that cylinder bore faces down
at an angle, since otherwise the support ring
could slip during assembly. Install piston with
Special Tool 34 3 000 to protect the cups
against damage.

Important: Note location of piston (14) and
stop screw (7).