Volvo Coupes/Sedans/Wagons 1970-1989 Repair Guide

Tank Assembly

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REMOVAL & INSTALLATION



All Models (Except 760 and 780, 1988 and Later)

Generally stated, the only reason to remove the fuel tank should be in cases of physical damage or to gain access to the rear body work for repairs. The tank can be drained in the car by using the fuel pump to pump most of the fuel through the system and collecting it at a disconnected hose near the tank or under the hood. Reconnect and secure the line after draining the system. Its easier if you schedule the work to occur when the tank is nearly empty.


CAUTION
The fuel system is under pressure. Release pressure slowly and contain spillage. Observe no smoking/no open flame precautions. When performing this work, always have a dry-chemical fire extinguisher handy and know how to use it. Use clean containers large enough to collect all the fuel drained out. Keep drained fuel out of the work area and tightly covered.

For all cars except the 1988 and later 760 and 780 series, after draining the tank:

  1. With the ignition key OFF and all electrical components (radio, heater, etc.) turned off, disconnect the negative battery cable.
  2.  
  3. In the trunk, remove the panels which cover the filler hose. Remove or roll back the trunk carpet or liner and remove the screws holding the access panel in the floor of the trunk.
  4.  
  5. Label and disconnect the filler, overflow and fuel return lines at the tank. It may be necessary to loosen or disconnect some lines at the filler neck as well.
  6.  
  7. Disengage wiring connectors and grounding connections, labeling as necessary.
  8.  
  9. Block the front wheels, jack the rear end and support the rear of the car with jackstands.
  10.  
  11. Under the car, clamp off and disconnect the hoses between the tank and the body lines. Depending on the model, there may be a mass of hoses around the fuel pump and accumulator. Since some of these components may be bolted to the tank (and be removed with it) look for the fuel lines coming from the body. Identify and disconnect as few lines as possible to make reconnection easier. Label everything.
  12.  
  13. Double check all four sides of the tank and the top surface. There should be no wires or hoses connecting the tank to the car. Check the security of all the plugs or clamps in the fuel lines.
  14.  
  15. Position the jack under center of the tank and use a broad, flat piece of wood between the jack and the bottom of the tank. Raise the jack until it just contacts the tank.
  16.  
  17. Depending on your model, it may be necessary to remove various heat shields or protective covers from the side of the tank or the body. Loosen and remove the tank retaining bolts. The jack should have enough elevation to support the tank in position until all the bolts are removed.
  18.  
  19. With the tank completely free and supported only by the jack, lower the jack about two inches and hold that position. Perform a final check for any line or wire still connected and check for possible points of interference in the downward path of the tank.
  20.  
  21. Balance the tank with one hand and slowly release the jack to lower the tank clear of the car. When the tank is clear of the car, the fuel sender and in-tank fuel pump (if so equipped) can be removed by unscrewing the locking ring on the top of the tank. Drain the remaining fuel immediately and store it safely. Remember that fuel vapors (fumes) are highly explosive-get the tank dry as soon as possible and keep it out of enclosed areas where fumes could be trapped.
  22.  
  23. When reinstalling the tank, make sure that the fuel sender and auxiliary pump is properly seated in its mounts and is not resting or binding on anything inside the tank. Make sure that any of the foam rubber insulators on the outside of the tank have not come off. Position the tank on the board and jack as before and elevate it into position. Install the mounts and/or retaining bolts to hold the tank to the car. Remove the jack from the tank area.
  24.  
  25. Reinstall any heat shields or covers which were removed for access.
  26.  
  27. Under the car, remove the plugs from each fuel line and connect it to the proper port on the tank or fuel system. Make sure you get things in the correct place or the car won't run. Make sure each connection is clean and tight, with the proper hose clamps as necessary. Double check for any kinks or points of interference.
  28.  
  29. Using the jack, remove the jackstands and lower the car to the ground. In the trunk, connect the filler, delivery and overflow hoses to the tank. Insure clean tight connections, using new clamps if necessary. If the larger hoses are difficult to fit onto the ports, a light coating of spray silicone inside the hose will ease the job.
  30.  
  31. Reconnect the wiring terminals to the top of the sender unit. Check that the connectors are not corroded or loose. If there is a tank-to-body ground wire, check the body connection for poor contact and/or corrosion and repair if necessary.
  32.  
  33. Check and secure any loosened connections at the fuel filler neck in the fender area. Double check all installation items, paying particular attention to loose hoses or hanging wires, untightened nuts, poor routing of hoses and wires (too tight or rubbing) and tools left in the area. Replace the trunk floor access panel, the trunk floor mat or carpet and install the cover panel over the filler hose.
  34.  
  35. Remove the gas cap and safely deliver clean, fresh fuel into the tank. Use a funnel and pour from a closed container. If you value your paint, don't spill fuel down the bodywork of the car. Replace the gas cap.
  36.  
  37. Reconnect the negative battery cable.
  38.  
  39. Turn the ignition key to the ON position for five seconds. Cycle it to OFF and back to ON for another 5 seconds. Turn it OFF and then start the engine. Although the two ON cycles partially primed the system, the engine may crank longer than normal until the correct pressures are developed and fuel reaches the engine.
  40.  
  41. After the engine has started and is running smoothly, shut it off and recheck every hose connection for any sign of leakage or seepage. Remember that the system is once again holding pressure. Be very careful when working around lines and fittings.
  42.  

760 and 780 Models, 1988 and Later

See Figures 1, 2, 3 and 4

These cars have a saddle type tank designed to fit around the revised rear axle design. The tank is constructed of heavy-duty plastic. The driveshaft runs through a tunnel in the tank and must be removed during tank removal. The tank has several heat shields and safety shields to guard it against damage from heat or driveshaft contact.


CAUTION
The fuel system is under pressure. Release pressure slowly and contain spillage. Observe no smoking/no open flame precautions. When performing this work, always have a dry-chemical fire extinguisher handy and know how to use it. Use clean containers large enough to collect all the fuel drained out. Keep drained fuel out of the work area and tightly covered.

  1. Because of a higher degree of sophisticated electronic components, all electrical components (radio, heater fan, etc) must be turned off as well as the ignition switch. Disconnect the negative battery cable. The electrical "spike" caused by this disconnection can destroy components in micro-processing units.
  2.  
  3. In the trunk, disconnect the left side drain hose. Remove the spare tire cover and the trunk mat. Remove the panel and cover for the fuel filler pipe.
  4.  
  5. Remove the access panel over the fuel level sender. Disconnect the fuel hoses at the sender and the wire connectors in the trunk. Press the rubber grommet out of the bodywork and remove the wire through the hole.
  6.  



Click image to see an enlarged view

Fig. Fig. 1: Unplug the fuel tank electrical connectors-location for 760 and 780 models

  1. Using a small pump and lengths of hose, drain the tank by sucking fuel out through the filler pipe hole in the fuel sender assembly. This is the only way to drain the tank. Removing the tank with fuel in it is NOT recommended. The added weight of the fuel (approximately 7.2 pounds per gallon/0.85 kg per liter) will imbalance the tank and damage the mounts during removal.
  2.  
  3. Block the front wheels, jack the rear end and support the rear of the car with jackstands.
  4.  
  5. From under the car, remove the three bolts holding the heat shield at the front of the tank and remove the shield.
  6.  
  7. Disconnect the front tank attachment by removing the two strap bolts. The outer bolts should be loosened about 3 / 8 inch but not removed. This will allow you to pull the straps out of the front attachment.
  8.  
  9. Remove the bracket under the tank and remove the nut for tank attachment point on the right side.
  10.  
  11. Gently pull the tank loose from the body. Let the tank rest on the front attachment. The tank is still retained at the rear and cannot come free of the car yet.
  12.  
  13. Mark the front and rear driveshaft (propeller shaft) so that they may be reassembled correctly. Remove the rear flange bolts. Slide the rear driveshaft loose from the splines at the front support bearing.
  14.  



Click image to see an enlarged view

Fig. Fig. 2: Disconnect the rear driveshaft at the points indicated by the arrows-1988-89 760 and 780 models

  1. Position a jack under center of the tank and use a broad, flat piece of wood between the jack and the bottom of the tank. Raise the jack until it just contacts the tank.
  2.  
  3. Remove the front tank attachment. Lower the tank slightly and pull it forward. On the top of the tank, remove the hose from the expansion tank port. Remove the tank from the car and remove the shield panels from the tank.
  4.  



Click image to see an enlarged view

Fig. Fig. 3: On 1988-89 760 and 780 models, don't forget the evaporative hose above the tank

  1. Unscrew the locking ring and remove the fuel sender assembly from the tank. Be careful of the wiring harness attached to the top. Remember that fuel vapors (fumes) are highly explosive-get the tank dry as soon as possible and keep it out of enclosed areas where fumes could be trapped.
  2.  
  3. When reinstalling the tank, secure the shield panels to the tank first. Install the fuel sender assembly, making sure it seats properly and is not damaged by hitting the baffles inside the tank during installation. The small arrows on the housing should align with the seam in the top of the tank. Position the wire harness around the tank hose connections.
  4.  



Click image to see an enlarged view

Fig. Fig. 4: Be sure to reinstall the safety shields

  1. Check that the foam insulator pads on the tank are in place and not crushed. Replace any as needed.
  2.  
  3. Loosen but do not remove the bolts in the rear strap mount. Using the jack and the board, position the tank into the car and fit it into the rear mount.
  4.  
  5. Reconnect the hose to the expansion port on the top of the tank and secure the clamp. Observe the placement of the right side tank mount and move the tank into its final position. Tighten the rear clamp bolts.
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  7. Install the front tank attachment and tighten the two outer bolts just a few turns. The tank is now resting in its mounts, lower at the front. Remove the jack from the area.
  8.  
  9. Install the drive shaft, observing the matchmarks made earlier. Replace and tighten the rear flange bolts.
  10.  
  11. Install the straps to the front mount, tighten the outer two bolts and then tighten the strap retaining bolts. Reinstall the heat shield over the front tank mount.
  12.  
  13. Reinstall the right side mount and the under-tank bracket.
  14.  
  15. Using the jack, remove the jackstands and lower the car to the ground.
  16.  
  17. Route the harness through the bodywork and into the trunk. Attach the wire to the clip on the sidemember under the trunk. Install the bolt for the ground connector and reconnect the harness and ground.
  18.  
  19. Reconnect the hoses to the tank sender unit, making sure all connections are clean and tight.
  20.  
  21. Remove the gas cap and safely deliver clean, fresh fuel into the tank. Use a funnel and pour from a closed container. If you value your paint, don't spill fuel down the bodywork of the car. Replace the gas cap.
  22.  
  23. Reconnect the negative battery cable.
  24.  
  25. Turn the ignition to the ON position. Listen for the fuel pump running and check for any system leaks. Check that the fuel gauge on the dash is registering properly. Remembering that the system has repressurized itself, attend to leaks or loose connectors.
  26.  
  27. In the trunk, replace the access panel over the fuel sender. Connect the drain hose on the left side and install the protective covers and panel to conceal the fuel filler hoses. Replace the spare tire cover and install the trunk mat.
  28.  

 
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