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Servicing fuel filter > < Testing tandem pump

A4 Mk1

Fuel supply system - Diesel engines
Servicing tandem pump - Vehicles with 4-cylinder engine (unit injector)
Removing and installing tandem pump
 
G20-0018

Special tools and workshop equipment required

  • ◆ V.A.G 1390
  • ◆ V.A.G 1390/1
  • ◆ V.A.G 1921
 
A10-0659

Removing

  • ‒ → Pull out oil dipstick -1- from guide tube.
  • ‒ Unclip dust covers.
  • ‒ Unscrew nuts -arrows- and remove engine cover.
  • ‒ Remove noise insulation located under engine cover.
  • ‒ Re-insert oil dipstick into guide tube.
 
N15-0234
  • ‒ → Pull off supply hose -1- (white marking) and return hose -2- (blue marking) from fuel filter.
  • ‒ Insert a suitable adapter from V.A.G 1390 into connecting hose.
  • ‒ Connect adapter with connecting hose to bleeder container V.A.G 1390/1.
  • ‒ Connect hand vacuum pump V.A.G 1390 with fluid receptacle V.A.G 1390/1 to return hose.
  • ‒ Operate hand vacuum pump until no more fuel comes out of return hose. Make sure that no fuel enters hand vacuum pump.
 
A10-0769
  • ‒ Unbolt coolant expansion tank and move clear to one side with coolant hoses connected.
  • ‒ → Detach air intake hose from charge air cooler -arrow-.
 
A10-0770
  • ‒ → Detach vent pipe -1- to air cleaner and vacuum pipe -2- to mechanical exhaust gas recirculation valve.
  • ‒ Disconnect air intake hose -3- from inlet connection.
 
A10-0771
  • ‒ → Unplug connectors -2- and -4-.
  • ‒ Disconnect vacuum hose -5- and move vacuum pipe clear from charge air pipe.
  • ‒ Remove bolt -1-.
  • ‒ Remove air intake pipe -3-.
 
A10-0755
  • ‒ → Disconnect hose connectors -arrows-.
  • ‒ Remove vacuum pipe -1-.
 
A15-0517
  • ‒ → Turn knurled nut -3- of main connector anti-clockwise.
  • ‒ Unplug main connector.
Warning
  • ◆ In extreme cases the fuel pipes/hoses or the fuel can reach a temperature of 100 C on vehicles with unit injector engine. Allow the fuel to cool down before disconnecting the pipes/hoses - acute danger of scalding.

  • ◆ Wear protective gloves.
  • ◆ Wear protective goggles.
  • ‒ Detach fuel hoses -1- and -2-.
 
A20-0611
  • ‒ → Remove bolts -arrows-.
  • ‒ Remove tandem pump from cylinder head.

Installing

Install in reverse sequence; note the following points:
 
A20-0611

Notes:

  • ◆ Always replace tandem pump seals.
  • ◆ Ensure that the drive lugs of the tandem pump coupling engage properly with the camshaft.
  • ‒ → Install tandem pump and tighten upper securing bolts to 20 Nm.
  • ‒ Tighten lower securing bolts to 10 Nm.
 
A15-0517
  • ‒ → Connect fuel hoses -1- and -2- to tandem pump.
  • ‒ Plug in main connector and turn knurled nut -3- clockwise.
  • ‒ Install vacuum pipe for brake servo.
  • ‒ Install charge air pipe.

Servicing fuel filter > < Testing tandem pump