Removing and installing ABS control unit J104/ABS hydraulic unit N55 — VW

Removing and installing
ABS control unit
J104
/
ABS hydraulic unit
N55
Special tools and workshop equipment required
Torque wrench
V.A.G 1331
Open ring spanner insert, AF 11 mm
V.A.G 1410/6
Universal joint
V.A.G 1410/7
Torque wrench
VAS 6854
Brake pedal actuator
V.A.G 1869/2
Assembly tool
V.A.G 1410/8
Sealing plug
5Q0 698 311
The transport protection for the contact pins must always be placed on the hydraulic unit after the control unit has been disconnected from the hydraulic unit.
No warranty can be assumed for hydraulic units without transport protection.
1
M10 sealing plugs
2
M12 sealing plugs
Removing
Location:
The
ABS control unit
J104
is bolted to the
ABS hydraulic unit
N55
and is located on the right in the engine compartment.
WARNING
Do not bend the brake lines in the area of the hydraulic unit!
Read out and note the existing control unit code.
If vehicle has a coded radio, note radio code or, if necessary, request it.
Disconnect battery
Electrical system
Rep. gr.
27
Battery; Disconnecting and reconnecting battery.
1.2 l TSI engines:
Remove pressure pipe and intake connecting pipe together with regulating flap control unit
Rep. gr.
24
Intake manifold; Removing and installing
regulating flap control unit
J808
.
Remove charge air hose
Rep. gr.
21
Charge air system; Assembly overview - charge air hose connections
.
Clamp off hose from coolant expansion tank and pull it off.
2.0 l diesel engines:
Remove centre plenum chamber bulkhead
General body repairs, exterior
Rep. gr.
50
Plenum chamber bulkhead; Removing and installing plenum chamber bulkhead
.
Remove connecting pipe between intake hose and turbocharger.
Remove toothed belt guard upper part.
Diesel engines with diesel particulate filter:
Release particulate filter (do not remove)
Rep. gr.
26
Emission control; Removing and installing particulate filter
.
Disconnect connector of
exhaust gas pressure sensor 1
G450
1
.
Remove bolt
2
.
Remove bracket
3
together with
exhaust gas pressure sensor 1
G450
, and lay it aside.
Remove nuts
4
.
Remove heat shield
5
upwards.
Unscrew nut
2
.
Remove cover for brake lines
1
.
Continuation for all models:
Release connector in direction of
arrow 1
.
Release connector in direction of
arrow 2
.
Apply
brake pedal actuator
V.A.G 1869/2
.
Connect bleeder bottle hose to front left brake caliper bleeder valve and rear left brake caliper bleeder valve and open bleeder valves.
Depress brake pedal at least 60 mm using
brake pedal actuator
V.A.G 1869/2
.
Close front left and rear left bleeder valves.
Do not remove
brake pedal actuator
V.A.G 1869/2
.
Place sufficient lint-free cloths under the control unit and hydraulic unit.
Note
No brake fluid must get onto the contacts.
First, mark the two brake lines
5
and
6
from brake master cylinder, and unscrew them from the hydraulic unit.
Immediately seal brake lines and threaded holes with
sealing plugs
1H0 698 311 A
.
Identify brake lines (brake calipers)
1
to
4
, unscrew and seal.
Turn hexagon fitted bolt out of retainer.
Pull off
ABS hydraulic unit
N55
with
ABS control unit
J104
and retainer sideways from damper rubbers of bracket and turn upside down.
Unbolt bracket from
ABS hydraulic unit
N55
in engine compartment and remove.
Remove
ABS hydraulic unit
N55
with
ABS control unit
J104
upwards out of dampers.
Installing
Installation is performed in reverse sequence; note the following:
Note
Do not remove
sealing plugs
1H0 698 311 A
from the new hydraulic unit until the respective brake lines are about to be installed.
If the
sealing plugs
1H0 698 311 A
are removed too early from the hydraulic unit, brake fluid can escape, and it can then no longer be guaranteed that the unit can be sufficiently filled and bled.
When installing, ensure that rubber dampers are not pressed out of bracket.
Before installing bracket of
ABS hydraulic unit
N55
into console, moisten rubber dampers with
polyethylene glycol
294435
.
Using
assembly tool
V.A.G 1410/8
, carefully fit brake lines.
Tighten brake lines using special tool assembly.
Remove
brake pedal actuator
V.A.G 1869/2
.
Bleed brake system
Chapter
.
Code radio.
Code
ABS control unit
J104
using
Vehicle diagnostic tester
.
To do this, basic setting of
steering angle sender
G85
,
lateral acceleration sender
G200
and
brake pressure sender
G201
must be performed.
Specified torques
Chapter
“
Assembly overview - control unit and hydraulic unit
”
Rep. gr.
10
Engine cover panel; Removing and installing engine cover panel
Electrical system
Rep. gr.
27
Battery; Assembly overview - battery
Chapter
“
Assembly overview - front brake caliper
”
Chapter
“
Assembly overview - rear brake caliper
”