Volkswagen Fox (2004 year). Manual - part 25

Special tools and workshop

equipment required
♦ Torque wrench - 5 to 50 Nm

(enc. 1/2") -VAG 1331-

♦ Vacuum pump -VAG 1390-
♦ Fluid container -

V.A.G 1390/1-

♦ Standart-type clamp pliers -

VAS 5024A-

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1. Fuel supply system components - remove and install     

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– Remove supply pipe -1- (white marking) and return pipe -2-

(blue marking) from the fuel filter.

– Connect the Vacuum pump -VAG 1390- with the Fluid con‐

tainer -VAG 1390/1- to return pipe.

– Activate Vacuum pump -VAG 1390- until no more fuel comes

from the return pipe. Take care not to suck fuel into the vaccum

pump.

– Remove vacuum hose -1- belonging to the servo brake from

auxiliary pump -4-.

– Remove supply pipe -2- (white marked) from auxiliary pump

-4-.

– Remove fastening screws -arrows-.
– Remove auxiliary pump -4- from cylinder head..

– Pull auxiliary pump -4- slightly upwards and remove return

pipe -3- (blue marking).

1.11.2

Installation

Installation is carried out by inverting the removal sequence, ob‐

serving the following:

Note

♦

Ensure proper seating of auxiliary pump coupling in camshaft.

♦

Always replace auxiliary pump seals.

– Fit return pipe -3- (blue marking) to auxiliary pump return con‐

nection.

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– Tighten lower securing bolts to 10 Nm.
– Fit supply pipe -2- (white marking) to auxiliary pump supply

connection and vacuum hose -1- from servo-assisted brake to

the auxiliary pump -4-.

– Connect pipe -1- (white marking) to fuel filter.
– Connect the Vacuum pump -VAG 1390- with the Fluid con‐

tainer -VAG 1390/1 - to return pipe.

– Activate Vacuum pump -VAG 1390- until no more fuel comes

from the return pipe. Take care not to suck fuel into the vaccum

pump.

– Fit return pipe -2- (blue marked) in the fuel filter.

1.11.3

Checking for internal leaks

Note

The tandem pump must be checked for internal leaks between

fuel side and oil side after reinstalling a used tandem pump, for

example after replacing or repairing a cylinder head and/or when

installing a "short" engine. When leaking it is possible for the fuel

to mix with the oil which may cause the engine to fail.

Special tools and workshop equipment required
♦ Tester -V.A.G 1687-

Procedure
– Pull fuel supply hose (white marking) 

⇒ Item 28 (page 39)

 and

fuel return hose (blue marking) 

⇒ Item 29 (page 39)

 off tandem

pump.

– Seal fuel return union on tandem pump with a plug. Secure

sealing plug with a spring-type clamp.

Prepare test unit -V.A.G 1687- as follows:

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– Connect test connection -5- to fuel supply union of tandem

pump using a commercially available compressed air connec‐

tion and a section of fuel hose. Use a spring-type clamp to

secure.

Note

To turn the pressure regulating valve -2- the knob must be pulled

upwards.

– Connect compressed air hose -1- (compressed air source) to

tester unit -V.A.G 1687- .

Note

If there is water in the sight glass, drain at water drain screw -6-.

– Open valve -3-.
– Adjust pressure to 1.0 bar with pressure regulating valve -2-.

Caution

The maximum test pressure lies by 1.3 bar and this must not

be exceed.

– Open valve -4- and wait until the test circuit is filled. If neces‐

sary readjust pressure to 1.0 bar.

– Close valve -3- to retain pressure and observe the pressure

drop over a period of 1 minute.

If the pressure does not drop the tandem pump can be reused, if

the pressure drops the tandem pump must be renewed.

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