A. Special Fuel Tank Pressure Test
Required:Pressure Test Tool No. US 2091, ordering # TU520910020VOA
(One test kit is supplied to dealers free of charge)
Test Procedure
- Place vehicle on hoist, do not lift.
- Drain fuel tank - use fuel cart TPH300NL020CGE (available through VWoA) or similar, down to fuel level below the seam (less than half full).
Caution:
Ensure that fuel cart static ground wire is connected to an unpainted surface of the vehicle.
- Lift vehicle to gain wheelhousing access.
- Remove right rear wheel.
- Remove right rear inner wheelhousing cover. Use penetrating oil on nuts. DO NOT BREAK STUDS. IF NECESSARY, USE A NUTBUSTER TO REMOVE NUT.
- Clamp both vacuum lines as shown. A.
- Lift vehicle completely.
- Clamp fuel supply and return lines. B.
- Remove exhaust hangers, allow exhaust system to rest on rear axle.
- Use kit, part number D 700 000 and prepare upper left fuel tank seam area for checking as follows:
Magnaflux Penetrant
Test Instructions
Kit Part Number D 700 000 contains
- 2 cans Cleaner
- 1 can Spotcheck (Penetrant)
- 1 can Developer
Test Sequence
Work only in well ventilated area. Wear goggles - avoid skin contact.
^ Pre-clean inspection area using spray on Cleaner sparingly, wipe clean with cloth
^ Apply Spotcheck Penetrant, allow minimum of 5 minutes drying time
^ Wipe Penetrant from surface with towel moistened with Cleaner.
Do not flood surface with Cleaner as sensitivity will be impaired.
^ Shake developer can thoroughly and spray on a thin film
^ Let dry
^ Inspect, crack will show as bright red line in white Developer background
WARNING
^ MATERIAL CAN BE HAZARDOUS TO HEALTH IF NOT USED ACCORDING TO INSTRUCTIONS CONTENTS UNDER PRESSURE
^ USE ONLY IN WELL VENTILATED AREA. AVOID CONTACT WITH EYES OR SKIN AND BREATHING OF VAPOR OR SPRAY MIST.
- Continue by installing the two (2) tank support pieces from the pressure test tool box, place the long support piece on front and the short support piece on rear of axle to support the fuel tank.
- Lower vehicle half way.
- Open trunk lid.
- Take pressure test tool out of box; use chain hangers from tool and carefully hook into opening of trunk lid hinges. (Cabriolet) or into inside trunk reinforcement panel (Scirocco).
- Remove gas cap and install special cap/hose combination from pressure test tool
- To ensure proper calibration of the pressure test tool gauge, clamp the hose between test tool gauge and fuel tank filler neck (Open both valves so knobs are in line with tool assembly.)
- Gauge needle must stabilize in red area (240-260 mbar).
- Connect shop-supplied compressed air.
- After calibration check, release clamp, thereby pressurizing tank up to the red area marked on gauge
Gauge will automatically stabilize within the 240 to 260 mbar (red marked area).
- Complete pressurization of tank may take up to 5 minutes.
Note:
At all times observe pressure gauge. Do not let pressure exceed red marked area.
- After gauge has reached between 240 and 260 mbar (red marked area) and stabilizes, close left shut-off valve (identified as (1) in illustration) and wait for 3 to 5 minutes to check gauge for any pressure loss.
- If pressure loss is noted, check that clamps applied to hoses are still in place
- If OK, check tank ventilation system for pressure leaks and correct
- Lift vehicle again and check prepared tank seam area for leak or hairline crack. Use a mirror and light for thorough inspection
If fuel moisture in "Developer" is detected, fuel tank needs to be replaced.
If only a crack shows in the "Developer" without fuel moisture, scrape off paint and smooth surface with fine steel wool and emery cloth and reapply "Cleaner" "Penetrant" and "Developer" to clean metal surface and re-check for crack emerging in "Developer" application.
- If no crack or fuel moisture shows in tank seam area - fuel tank is OK - clean and repaint area
Continue all remaining steps of pressure test procedure "A".
- If crack or fuel moisture becomes visible - replace tank. (Follow instructions described in Procedure "B".)
- Remove clamping devices from fuel supply and return lines.
- Lower vehicle close to floor.
- To lower fuel tank pressure before removing clamps from gravity valve vacuum hoses, start engine, let run for approximately 1 minute before removing clamps.
- Caution:
Do not relieve fuel tank pressure by any other means.
- After pressure test tool gauge reads approximately 140-160 mbar, stop engine and remove special cap/hose combination from tank filler neck.
- Replace gas cap.
- Remove pressure test tool and place carefully back into pressure test tool box.
^ At this point proceed to Replacement Procedure "B", if a tank replacement is necessary.
^ If tank does not need replacement, continue to:
- Remove gravity valve, replace with new valve, part number 133 201 753. Use two (2) new hose clamps, part number N 024 528 1.
- Reinstall wheelhousing cover and wheel
- Lift vehicle
- Remove both tank supports and place in pressure test tool box; reconnect exhaust system hangers.
- Lower vehicle completely
- Install and tighten right rear wheel
- Start engine and check operation