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

Removing and installing
ABS control unit
J104
/
ABS hydraulic unit
N55
, petrol engine
Special tools and workshop equipment required
Torque wrench
V.A.G 1331
Torque wrench
V.A.G 1410
Brake pedal depressor
V.A.G 1869/2
Sealing plugs from repair kit, part number 1 H0 698 311 A
2
Sealing plug M10
3
Sealing plug M12
Location:
The
ABS control unit
J104
is bolted to the
ABS hydraulic unit
N55
and is located on the right in the engine compartment.
Removing
WARNING
Do not bend the brake lines in the area of the
ABS hydraulic unit
N55
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
.
If fitted, remove engine cover panel
Rep. gr.
10
Engine cover panel; Removing and installing engine cover panel
.
Remove heat shield
1
if present.
To do this, unclip heat shield
1
from bracket
2
arrow
.
Unclip line guide.
Push down locking slide
arrow A
.
Release catch in direction of
arrow B
.
Pull off electrical connector
1
.
Apply
brake pedal depressor
V.A.G 1869/2
.
Connect hose of bleeder bottle
1
to bleeder valve of front left brake caliper.
Open bleeder valve.
Connect hose of bleeder bottle
1
to bleeder valve of rear left brake caliper.
Open bleeder valve.
Depress brake pedal at least 60 mm using
brake pedal depressor
V.A.G 1869/2
.
Close front left and rear left bleeder valves.
Do not remove
brake pedal depressor
V.A.G 1869/2
.
Note
Ensure no brake fluid gets onto contacts.
Pull cover off bulkhead and unclip brake lines.
First, mark brake lines
5
and
6
.
Unscrew brake lines
5
and
6
from
ABS hydraulic unit
N55
.
Immediately seal brake lines and open connections with
sealing plugs from repair kit
1H0 698 311 A
or suitable plugs from
engine bung set
VAS 6122
.
Mark and then unscrew remaining brake lines (brake calipers)
arrows
.
Immediately seal brake lines and open connections with
sealing plugs from repair kit
1H0 698 311 A
or suitable plugs from
engine bung set
VAS 6122
.
Pull
ABS control unit
J104
together with
ABS hydraulic unit
N55
upwards out of dampers
arrow
.
Installing
Install in reverse order. Note the following points:
Note
Do not remove sealing plugs from new
ABS hydraulic unit
N55
until respective brake line is about to be installed.
If sealing plugs are removed too early from the
ABS hydraulic unit
N55
, brake fluid can escape, and it can then no longer be guaranteed that the unit can be sufficiently filled and bled.
When installing the
ABS hydraulic unit
N55
, ensure that the rubber dampers are not pressed out of the bracket.
Tightening sequence:
Remove
brake pedal depressor
V.A.G 1869/2
.
Bleed brake system
Chapter
.
Code radio.
Code
ABS control unit
J104
J104
using
Vehicle diagnostic tester
in "Guided Fault Finding" mode.
To do this, carry out basic setting of the
steering angle sender
G85
, the
lateral acceleration sender
G200
, the
longitudinal acceleration sender
G251
and the
brake pressure sender
G201
.
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
”