Hydraulic unit, brake servo/ brake master cylinder - exploded view — AUDI
Hydraulic unit, brake servo/ brake master cylinder - exploded view on Audi: factory workshop procedure. Full factory text, tools and checks.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📋 Procedure
ℹ️ Torque figures below come verbatim from workshop data — always cross-check against your vehicle's factory manual before final tightening.
Audi
Audi Q7
2007
Running gear
Brake system
Edition
03.2013
Hydraulic unit, brake servo/ brake master cylinder - exploded view
ABS control unit
J104
Location: in engine compartment (right-side) below engine control unit
Caution
ABS control unit -J104- and ABS hydraulic unit -N55- must not be separated
Removing and installing
Chapter
ABS hydraulic unit
N55
Location: in engine compartment (right-side) below engine control unit
Caution
ABS control unit -J104- and ABS hydraulic unit -N55- must not be separated
Removing and installing
Chapter
Brake line
Brake master cylinder/primary piston circuit to hydraulic unit
Marked on hydraulic unit with
DK
Brake line
Brake master cylinder/secondary piston circuit to hydraulic unit
Marked on hydraulic unit with
SK
Brake line
To rear left caliper via intermediate piece
Marked on hydraulic unit with
HL
Brake line
To front right brake caliper via intermediate piece
Marked on hydraulic unit with
VR
Brake line
To front left brake caliper
Marked on hydraulic unit with
VL
Brake line
To rear right caliper via intermediate piece
Marked on hydraulic unit with
HR
Intermediate piece
Bracket
Note
Bracket
10
and bolts
12
are not fitted on all vehicles
Electronic parts catalogue
.
Flange bolt
Tightening torque: 5 Nm
Hexagon bolt
Tightening torque: 8 Nm
Note
Bracket
10
and bolts
12
are not fitted on all vehicles
Electronic parts catalogue
.
Buffer
Gasket
For brake servo
Brake servo
Removing and installing
Chapter
Fitting location: In engine compartment (left-side)
Functional check:
With the engine switched off, firmly depress the brake pedal several times (this reduces the vacuum present in the servo unit).
Then hold brake pedal in applied position employing moderate force and start engine. If the servo unit is working properly, the pedal will give slightly under foot (servo assistance becomes activated).
Potentiometer for brake servo diaphragm movement
Note
There is no provision for removal.
Sealing plug
Connection for vacuum hose
Vacuum hose
Insert into brake servo unit
Seal
Self-locking hexagon nut
Tightening torque: 49 Nm
Always renew if removed
Bracket
Brake master cylinder
Removing and installing
Chapter
Cannot be repaired. If faulty, renew complete.
Sealing plug
Moisten with brake fluid and press into brake fluid reservoir
Brake fluid reservoir
Filler cap
With float warning indicator sender
Connecting brake lines from brake master cylinder to hydraulic unit
A
Hydraulic unit to brake master cylinder (primary piston circuit)
Marked on hydraulic unit with
DK
B
Hydraulic unit to brake master cylinder (secondary piston circuit)
Marked on hydraulic unit with
SK
1
Hydraulic unit to front left brake caliper
Marked on hydraulic unit with
VL
2
Hydraulic unit to front right brake caliper via intermediate piece
Marked on hydraulic unit with
VR
3
Hydraulic unit to rear right brake caliper via intermediate piece
Marked on hydraulic unit with
HR
4
Hydraulic unit to rear left brake caliper via intermediate piece
Marked on hydraulic unit with
HL
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.