Removing and installing ABS control unit J104/ABS hydraulic unit N55, Audi A1 quattro — AUDI

Removing and installing
ABS control unit
J104
/
ABS hydraulic unit
N55
, Audi A1 quattro
Note
When renewing
ABS control unit
J104
/
ABS hydraulic unit
N55
, select the
“Replace”
function for the
ABS control unit
J104
/
ABS hydraulic unit
N55
using
Vehicle diagnostic tester
,
Guided Functions
.
Special tools and workshop equipment required
Torque wrench
V.A.G 1331
Torque wrench
V.A.G 1410
Hose clamps up to 25 mm
3094
Brake pedal actuator
V.A.G 1869/2
Reservoir from
brake filling and bleeding equipment
VAS 5234
Engine bung set
VAS 6122
Hose clip pliers
VAS 6340
Sealing plugs (
repair kit
1H0 698 311 A
)
Transport protection for contact pins (foam)
M10 sealing plugs
M12 sealing plugs
Removing
Remove noise insulation
General body repairs, exterior
Rep. gr.
66
Noise insulation; Exploded view - noise insulation
.
Caution
Risk of irreparable damage to electronic components when disconnecting battery
Observe steps required when disconnecting battery.
Disconnect battery
Electrical system
Rep. gr.
27
Battery; Disconnecting and connecting battery
.
Remove engine cover panel
Rep. gr.
10
Engine cover panel; Removing and installing engine cover panel
.
Remove bolt
arrow
.
Release hose clips
1
and
3
and move air pipe
2
aside with hose connected.
Release hose clip
2
.
Remove intake hose between air pipe and turbocharger.
Seal off turbocharger using clean plugs from
engine bung set
VAS 6122
.
Detach ACF line
2
from cylinder head cover.
Remove bolts
3
.
Detach crankcase breather pipe with heat shield from cylinder head cover.
To do this, release hose clip
1
.
Press locking slide
2
downwards in direction of
arrow
.
Release locking bar
1
securing connector
3
on
ABS control unit
J104
.
To do this, press locking bar
1
downwards in direction of
arrow
.
Unplug connector
3
towards front.
WARNING
Risk to health
Brake fluid is poisonous and must NOT be drawn off by sucking through a hose.
Always wear chemical-resistant protective gloves to prevent brake fluid from contacting skin.
Always observe the relevant environmental regulations for disposal.
Risk of malfunction if brake fluid comes into contact with fluids containing mineral oils.
Do not under any circumstances allow brake fluid to come into contact with fluids that contain mineral oils (e.g. oil, petrol, cleaning agents). Protective gloves must be free of oil and grease.
Risk of damage to paintwork surfaces
Due to its corrosive effect, brake fluid must not be allowed to come into contact with paintwork. Rinse off brake fluid spillages immediately using plenty of water.
Insert
brake pedal actuator
V.A.G 1869/2
between brake pedal and driver's seat. Depress brake pedal by at least 60 mm.
Note
This closes the valves in the brake master cylinder and stops the brake fluid reservoir from running empty.
Attach bleeder hose
1
of bleeder bottle to bleeder screw of front left brake caliper.
Open bleeder screw.
Attach bleeder hose
1
of bleeder bottle to bleeder screw of rear left brake caliper.
Open bleeder screw.
Close bleeder screws (front left and rear left).
Do not remove
brake pedal actuator
V.A.G 1869/2
.
Place sufficient lint-free cloths under the
ABS hydraulic unit
N55
.
Clamp off coolant hoses with
hose clamps
.
Release hose clips
1
and
2
and disconnect coolant hoses from heat exchanger for heater.
Remove bolts
2
.
Detach heat shield
1
.
Carefully open retainer
2
at retaining tab
arrow
.
Unclip refrigerant line
1
.
Disconnect fuel lines
arrows
at connection in engine compartment (right-side).
Move fuel lines aside.
Release connector
2
and unplug.
Unscrew securing bolt
3
.
Move coolant expansion tank
1
to one side.
Remove bolts
arrows
and detach pendulum support.
Remove bolts
1
to
4
from engine mounting.
Pull engine 3.5 cm forwards in direction of
arrow
at engine mounting.
Unclip brake lines
1
at retainers
arrows
.
Caution
Risk of damage to brake lines
Do not attempt to bend to a different shape.
Make sure that no brake fluid gets onto contacts.
First mark the two brake lines
A
and
B
coming from the brake master cylinder.
Unscrew brake lines from
ABS hydraulic unit
N55
.
Mark brake lines
1
to
4
and unscrew brake lines.
Seal open connections immediately using clean sealing plugs from
repair kit
1H0 698 311 A
.
Note
Make sure brake fluid does not get into connector housing of control unit. This can result in corrosion of the contacts and failure of the system.
Use compressed air to carefully clean connector housing if necessary.
Remove nuts
5
and
6
.
Detach bracket together with hydraulic control unit.
Turn bracket so that nuts are accessible.
Loosen three nuts
arrows
securing rubber dampers until rubber dampers can be turned.
Unscrew top nut (located at side) as far as shoulder on stud.
Lift hydraulic control unit
1
out of bracket in direction of
arrow
and remove.
Note
Fit transport protection after removing hydraulic control unit.
No warranty claims for the hydraulic control unit can be accepted if the transport protection is not fitted.
Installing
Installation is performed in reverse sequence; note the following:
Note
Do not remove the sealing plugs from the new hydraulic control unit until you are ready to fit the corresponding brake line.
If the sealing plugs are removed from the hydraulic control unit too soon, brake fluid may escape and it may not be possible to fill and bleed the unit properly.
To facilitate installation, moisten the rubber mountings in the bracket slightly with water.
To facilitate installation, first insert all brake lines in the hydraulic unit.
Then tighten the brake line connections.
Fit hydraulic control unit
1
in bracket.
Caution
Malfunctions can occur if the unit is not fitted securely.
Make sure that the rubber dampers are fitted correctly in the bracket when installing.
After installation, check that the
ABS hydraulic unit
N55
is seated securely, otherwise malfunctions can occur.
Remove sealing plugs from new hydraulic control unit.
Insert all brake lines and tighten connections.
Clip brake lines
1
into retainers
arrows
on plenum chamber partition panel.
Remove
brake pedal actuator
V.A.G 1869/2
.
Bleed brake system
Chapter
.
Bleed clutch system
Rep. gr.
30
Clutch mechanism; Bleeding clutch hydraulics
.
Install engine cover panel
Rep. gr.
10
Engine cover panel; Removing and installing engine cover panel
.
Connect battery
Electrical system
Rep. gr.
27
Battery; Disconnecting and connecting battery
.
Check coolant level
Rep. gr.
19
Cooling system/coolant; Draining and filling cooling system
.
When renewing
ABS control unit
J104
/
ABS hydraulic unit
N55
, select the
“Replace”
function for the
ABS control unit
J104
/
ABS hydraulic unit
N55
using
Vehicle diagnostic tester
,
Guided Functions
.
WARNING
Risk of accident!
Make sure that the brakes work properly before the vehicle is driven on the road.
Tightening torques
Component
Tightening torque
Bracket for hydraulic control unit to body
20 Nm
Nut securing rubber damper
8 Nm
Brake lines to hydraulic control unit
Chapter
“
Exploded view - control unit and hydraulic unit, Audi A1
”
Crankcase breather pipe
Rep. gr.
21
Turbocharger; Exploded view - turbocharger
Coolant expansion tank
5 Nm
Pendulum support
Running gear, axles, steering
Rep. gr.
40
Subframe; Exploded view - subframe
Engine mounting
Rep. gr.
10
Assembly mountings; Exploded view - assembly mountings
Heat shield
2.5 Nm