Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1978 Subaru GF Automatic TransFACTORY OEM SERVICE PROCEDURE
System Test
- Drain gasoline from fuel tank and place fuel cap tightly on filler neck. Disconnect hose from canister and fuel delivery hose from pipe under the vehicle.
- Connect a water column manometer that measures more than 15.8 in. water to hose. See Fig 1.
- Apply compressed air into canister side of evaporation hose until manometer indicates 14.2 in. water. Air pressure MUST NOT exceed 2.13 psi (.5 kg/cm2 ) during this test.
- System is functioning correctly if it takes 5 minutes or longer for water in column to drop 1.97 in. water.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.