VW Golf manuals

Volkswagen Golf Service & Repair Manual: Removing and installing brake servo, LHD vehicles

Special tools and workshop equipment required
   
Torque wrench -V.A.G 1331-
 

Removing and installing brake servo, LHD vehicles

Torque wrench -V.A.G 1410-
Tool inserts (11 mm) -V.A.G 1331/2-
 

Removing and installing brake servo, LHD vehicles

Brake filling and bleeding equipment -VAS 5234-
 

Removing and installing brake servo, LHD vehicles

Sealing plug repair kit -1H0 698 311 A-
Hot air blower, e.g. hot air blower -VAS 1978/14A-
 

Removing and installing brake servo, LHD vehicles

Fitting locations:
1 -  ABS control unit -J104- and ABS hydraulic unit -N55-
2 -  Brake servo
3 -  Brake system pressure accumulator -VX70-
Removing:
–  Observe safety precautions when working in the area of high-voltage components → Chapter.
–  Observe the risk classification of the high-voltage system → Electric drive; Rep. gr.00.
 

Removing and installing brake servo, LHD vehicles

Danger to life due to high voltage
The high-voltage system is under high voltage. If high-voltage components are damaged, there is a risk of severe or fatal injury due to electric shock.
–  Carry out visual inspection of high-voltage components and cables.
–  Never use cutting or forming tools, or any others with sharp edges.
–  Never use heat sources such as welding, soldering, thermal bonding or hot air.
 
 
–  Read and note code of brake servo control unit -J539- → Vehicle diagnostic tester.
–  Disconnect battery → Electrical system; Rep. gr.27.
–  Remove power and control electronics for electric drive -JX1- → Electrical system; Rep. gr.93.
–  Remove bracket for power and control electronics for electric drive -JX1- → Electrical system; Rep. gr.93.
–  Release high-voltage cables from bracket and lay to side → Electrical system; Rep. gr.93.
–  Remove bracket for high-voltage cables on the gearbox.
   
–  Release and pull off connector -1- for brake fluid level warning contact -F34--2- on brake fluid reservoir -3-.
 

Removing and installing brake servo, LHD vehicles

–  Release connector -2- and pull it off brake servo -1-.
 

Removing and installing brake servo, LHD vehicles

–  Pull locking slide (red) -1- towards front.
–  Press release tab -3- on connector -4-.
–  Release latch -2- and pull connector -4- off brake servo -5-.
Ensure no brake fluid gets onto contacts.
–  Place sufficient lint-free cloths in area of engine, subframe and gearbox.
Never allow brake fluid to come into contact with fluids that contain mineral oils (e.g. oil, petrol, cleaning agents). Mineral oils damage the plugs and seals in the brake system.
Brake fluid is poisonous and must never be sucked out by mouth through a hose. Because of its caustic properties, it must also not come into contact with paintwork.
Do not reuse drawn-off brake fluid.
Always observe the relevant environmental regulations for disposal.
–  Remove dash panel trim in driver footwell → General body repairs, interior; Rep. gr.68.
 

Removing and installing brake servo, LHD vehicles

–  Fold down floor covering -1- in -direction of arrow-.
 

Removing and installing brake servo, LHD vehicles

–  Loosen nuts -3 and 4- on brake servo as far as possible.
Brake lines must not be disconnected yet.
  Note
A second mechanic is required for further removal.
–  Depress brake pedal firmly and hold.
–  Have the second mechanic grasp the brake servo and pull it towards front.
  Note
By doing so, the bonded joint between the brake servo and the plenum chamber bulkhead will be separated.
Ensure that the brake lines are not bent.
If the bonded joint cannot be separated, the nuts must be unscrewed.
Risk of damage to the plenum chamber bulkhead due to improper separation of the bonded joint.
Never lever the brake servo off the plenum chamber bulkhead to separate the bonded joint.
–  Separate brake pedal from brake servo → Chapter.
–  Draw off as much brake fluid as possible from brake fluid reservoir using brake filling and bleeding equipment -VAS 5234-.
 

Removing and installing brake servo, LHD vehicles

–  Unscrew bolt -2- and carefully pull off brake fluid reservoir -1- upwards.
 

Removing and installing brake servo, LHD vehicles

–  Mark position of brake lines -2 to 4- on brake master cylinder -1-.
–  Unscrew brake lines -2 to 4- from brake master cylinder -1-.
–  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-.
–  Unscrew brake line -2- from brake system pressure accumulator -VX70- and remove it.
 

Removing and installing brake servo, LHD vehicles

–  Unscrew nuts -3 and 4- from brake servo.
–  If brake servo gets jammed in holes, loosen both remaining nuts -1 and 2- on the mounting bracket.
–  Carefully pull brake servo off plenum chamber bulkhead.
–  Carefully remove brake servo from the vehicle.
 

Removing and installing brake servo, LHD vehicles

–  Remove adhesive residue -arrows- from brake servo -2- and plenum chamber bulkhead -1-.
–  To do so, apply gentle heat from hot air blower to the adhesive residue and pull it off.
–  Thoroughly clean surfaces.
Installing:
Install in reverse order. Note the following points:
–  Renew seal between brake servo and plenum chamber bulkhead → Item.
–  Carefully insert brake servo and tighten nuts hand-tight.
–  Connect brake pedal to brake servo → Chapter.
–  Bleed brake system → Chapter.
–  Subsequently bleeding the brake system → Chapter.
–  Code brake servo control unit -J539- → Vehicle diagnostic tester.
–  Perform basic setting for electromechanical brake servo → Vehicle diagnostic tester.
Specified torques
→ Chapter „Assembly overview - brake servo/brake master cylinder, LHD vehicles“
→ Chapter „Assembly overview – Brake system pressure accumulator -VX70-“
→ Electrical system; Rep. gr.93
→ Electrical system; Rep. gr.27.
→ General body repairs, interior; Rep. gr.68
→ Running gear, axles, steering; Rep. gr.48.
 

Removing and installing brake servo, LHD vehicles

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