Volkswagen Front Wheel Drive 1974-1989 Repair Guide

Fuel Filter

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RELIEVING FUEL SYSTEM PRESSURE



Engines equipped with electric fuel pumps maintain fuel pressure even when the engine has not been run. This residual pressure may remain in the fuel system for several hours after the engine is shut down.

To relieve the fuel system pressure, perform the following:

  1. Start the engine and allow it to run at idle speed.
  2.  
  3. Locate the fuel pump electrical connector and disconnect it while the engine is running.
  4.  
  5. Operate the engine until it runs out of fuel and stops.
  6.  
  7. Remove the fuel filler cap.
  8.  
  9. Disconnect the negative battery cable.
  10.  

Have a container ready to catch the fuel that will squirt out when you loosen the clamps or couplings on the fuel system components you are working on. Wrap the connection with a rag and slowly crack the connection to vent any residual pressure from the system. Once all the pressure is relieved, loosen the connection.

  1. Proceed with the necessary fuel system component repairs. When finished, engage the fuel pump connector and connect the negative battery cable. Don't forget to install the fuel filler cap.
  2.  

REMOVAL & INSTALLATION




CAUTION
Never smoke when working around gasoline! Avoid all sources of sparks or ignition. Gasoline vapors are EXTREMELY volatile! This procedure will cause a small fuel spill. Make sure the work area is well ventilated and take appropriate fire safety precautions.

Gasoline Engines

Carbureted engines with mechanical fuel pumps have a strainer in the top cover of the fuel pump. Some later models are equipped with an additional inline fuel filter. These filters are small, usually made of plastic and are attached to the fuel line by clamps.

On fuel injected models, the filter removes particulate matter from the fuel system which might clog the fuel distributor or the injectors. The fuel filter is installed on the pressure side of the pump. On some fuel injected models, the fuel filters are large, metal containers. On the other fuel injected models, a small inline filter is used. Arrows on the filter point in the direction of fuel travel (the filter must be installed with the arrows pointing in the direction fuel flow). Some fuel filters are equipped with banjo type fittings, while some use O-ring seals and others may just use hose clamps. Banjo type fittings use metal gaskets to seal the fitting against the filter housing. Always replace these gaskets when replacing the fuel filter. If the fuel filter has O-ring type seals, these must be replaced also.

On 1985-89 models (except 1985-87 Cabriolet), a "lifetime" fuel filter is used. According to the manufacturer, unless the fuel system is damaged or contaminated, the filter is large enough to handle all normal fuel filtering requirements for the life of the engine. However, it is recommended to replace the filter if fuel system contamination is suspected, and to ease the load on the fuel pump on higher mileage vehicles.

CARBURETED MODELS

See Figures 1 and 2

It is recommended to clean the fuel pump strainer and replace the fuel filter (if equipped) at 30,000 mile (48,000 km) intervals. The filter is located in the engine compartment.

  1. Disconnect the negative battery cable.
  2.  
  3. Have a pan ready to catch the fuel that will run out of the fuel pump. Disconnect and plug the hose from the fuel pump cover.
  4.  
  5. Remove the center screw, then remove the cover and strainer.
  6.  
  7. Inspect the strainer for damage, replace if necessary. If it is usable, clean it with compressed air.
  8.  
  9. Install the strainer using new gaskets. On some models, be sure to align the notch in the cover with the groove in the body. Tighten the screw until it is snug.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: Fuel pump strainer on carbureted engines

  1. Connect the hose to the pump cover. Use a new clamp if the old one is damaged.
  2.  
  3. If equipped with an inline filter, disconnect and plug the hoses from the filter.
  4.  
  5. Install the new filter in the proper direction (make sure the arrows follow the direction of fuel flow). Use new hose clamps if the old ones are damaged.
  6.  
  7. Wipe any spilled fuel with a rag.
  8.  
  9. Connect the negative battery cable, then start the engine. Check for any leaks.
  10.  



Click image to see an enlarged view

Fig. Fig. 2: Some carbureted engines are also equipped with an inline filter

FUEL INJECTED MODELS-EXCEPT 1985-89 CABRIOLET, FOX, GOLF, GTI AND JETTA

See Figure 3

It is recommended for the filter to be replaced at 30,000 mile (48,000 km) intervals except on 1984 Quantum and Scirocco, which is to be replaced at 60,000 mile (96,000 km) intervals. The filter is located in the engine compartment.

  1. Relieve the pressure in the system following the procedures outlined in this section.
  2.  
  3. Remove the fuel filter mounting nuts and lift the filter from the mounting bracket.
  4.  

Always use a line or flare nut wrench on the fuel fittings and a back-up wrench to hold the filter, or the fuel lines may become damaged.

  1. Place a container under the filter to catch the excess fuel and cover the fuel line connections with a rag. Disconnect the fuel lines, then remove the filter.
  2.  

To install:
  1. Position the filter and connect the fuel lines. Torque the fittings (using a crow's foot attachment) to 14 ft. lbs. (20 Nm).
  2.  
  3. Install the filter to the mounting bracket. Tighten the nuts until snug.
  4.  
  5. Wipe any spilled fuel with a rag.
  6.  
  7. Connect the negative battery cable, then start the engine. Check for any leaks.
  8.  



Click image to see an enlarged view

Fig. Fig. 3: On fuel injected models through 1984, the fuel filter is usually located in the engine compartment

1985-89 CABRIOLET, FOX, GOLF, GTI AND JETTA

See Figure 4

On 1985-87 Cabriolet, replace the filter at 30,000 mile (48,000 km) intervals. All other models are equipped with a "lifetime" filter. It is recommended that these filters be replaced if fuel system contamination is suspected or on high mileage vehicles to ease the load on the fuel pump. The filter is located in the fuel pump assembly, mounted under the vehicle, in front of the fuel tank.

  1. Relieve the fuel system pressure following the procedure outlined in this section.
  2.  
  3. Raise and safely support the rear of the vehicle. Have a pan ready to catch the fuel that may run out of the reservoir.
  4.  
  5. Have a rag handy and wear safety glasses when loosening the fittings. The system may be under pressure and fuel could be sprayed.
  6.  

Always use a back-up wrench to hold the filter or the fuel lines may be damaged.

  1. Hold the filter with a 19mm or 22mm wrench, then loosen the fittings with a 17mm wrench. Have the catch pan ready.
  2.  
  3. Disconnect the fuel lines, loosen the mounting bracket, then remove the filter.
  4.  

To install:
  1. Install the new filter but do not tighten the mounting bracket yet.
  2.  
  3. Make sure all fittings and sealing surfaces are clean. Install the banjo bolts with new copper gaskets and/or sealing rings. Torque to 14 ft. lbs. (20 Nm).
  4.  
  5. Tighten the mounting bracket nuts until snug. Wipe any spilled fuel with a rag.
  6.  
  7. Lower the vehicle, then connect the negative battery cable. Start the engine and check for leaks.
  8.  



Click image to see an enlarged view

Fig. Fig. 4: On fuel injected engines after 1984, the filter can be found under the car just forward of the fuel tank

Diesel Engines

Two styles of fuel filters are used with diesel engines, both are canister types. Depending on the year and model, the filter canister is either threaded onto a mounting base or secured by clamps. Clamp mounted filters are usually found on 1985-89 Golf and Jetta.

The filter is usually mounted on the passenger's side of the vehicle (next to the air cleaner) on the Rabbit, Golf and Jetta, and next to the brake master cylinder on the Dasher and Quantum.

FILTER MOUNTED BELOW BASE

See Figures 5 and 6

  1. Disconnect the negative battery cable.
  2.  
  3. Open the fuel filler cap to relieve any pressure that may be in the tank.
  4.  
  5. Loosen the drain plug at the bottom of the canister and drain the fuel into a container. Reinstall the drain plug.
  6.  



Click image to see an enlarged view

Fig. Fig. 5: The drain plug is located at the bottom of the filter canister

  1. Use a band wrench to loosen the canister from the base, then remove by hand. Discard the old filter canister.
  2.  

To install:
  1. Pour a small amount of clean diesel fuel into the filter (DO NOT use fuel from the old filter), then apply a thin film of diesel fuel to the mounting gasket.
  2.  
  3. Install the filter and tighten by hand. Wipe any spilled fuel with a rag. Don't forget to tighten the fuel filler cap.
  4.  
  5. Connect the negative battery cable, then start the engine. Accelerate the engine several times until the engine is running smoothly (this will clear the air bubbles in the fuel system). Allow the engine to idle and check for fuel leaks.
  6.  



Click image to see an enlarged view

Fig. Fig. 6: The filter should be hand tightened only; do not use a strap wrench

CLAMP MOUNTED

See Figure 7

  1. Disconnect the negative battery cable.
  2.  
  3. Open the fuel filler cap to relieve any pressure that may be in the tank.
  4.  
  5. Disconnect and plug the fuel lines from the filter.
  6.  

Some models may be equipped with a flow control valve on the filter. Once the two filter lines are disconnected, remove the clip from the control valve (located on top of the filter), then remove the valve leaving the two lines connected. Position the valve and the lines off to the side. This valve is delicate, so be careful during removal and installation.



Click image to see an enlarged view

Fig. Fig. 7: Some clamp mounted filters are equipped with a flow control valve. Always use new O-rings when replacing the filter

  1. Loosen the mounting clamp nut/screw, then lift the filter assembly straight up. Discard the old filter.
  2.  

To install:
  1. Install the new filter onto the mounting clamp. If there are arrows indicating fuel flow direction, they point towards the front of the vehicle. Tighten the mounting nut/screw until the filter is secure.
  2.  
  3. On models equipped with a flow control valve, install new control valve O-ring seals. Also, lubricate the seals with clean diesel fuel before installing the valve on the filter. Inspect the retaining clip and replace it if damaged.
  4.  
  5. Connect the fuel lines to the filter. Use new clamps if they are damaged. Don't forget to tighten the fuel filler cap.
  6.  
  7. Connect the negative battery cable, then start the engine. Accelerate the engine a few times (this will clear the air bubbles in the fuel system) and check for fuel leaks.
  8.  

 
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