🔧 GLA - Fuel Pump Replacement

The fuel pump on your GLA is inside the fuel tank as a module that supplies pressurized fuel to the engine. Replacement usually happens from inside the cabin under the rear seat (no tank drop), but you must work cleanly and safely to avoid fuel leaks and fumes.

Assumption: Your GLA uses an in-tank fuel pump module accessed under the rear seat; fastener/lock-ring torque can vary by production—use torque where listed and alignment marks where noted.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

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⚠️ Safety & Precautions

• 🧯 Work outside or in a very well-ventilated area; fuel vapors are flammable.
• 🔥 No smoking, no heat guns, no shop lights with hot bulbs; keep sparks away.
• 🔋 Disconnect the negative battery terminal to prevent accidental sparks.
• 🧤 Wear nitrile gloves and safety glasses; fuel can irritate skin/eyes.
• 🧼 Clean the area before opening the tank; dirt in the tank can damage the new pump.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" ratchet
• 3/8" ratchet
• 3" extension
• Torx T20 bit
• Torx T25 bit
• Trim removal tool (plastic)
• Small flathead screwdriver
• Pick tool
• Fuel pump lock ring wrench (specialty)
• Brass punch (specialty)
• Small hammer
• Needle-nose pliers
• Shop rags
• Catch pan (fuel-safe)
• Torque wrench (5–60 Nm range)
• Nitrile gloves
• Safety glasses
• Fire extinguisher (Class B)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• In-tank fuel pump module - Qty: 1
• Fuel pump module tank seal O-ring/gasket - Qty: 1
• Fuel line retaining clips (if damaged) - Qty: 1

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📋 Before You Begin

• 🅿️ Park on level ground, set the parking brake, and open the fuel door to release any slight tank vapor pressure.
• 🧰 Keep rags and a catch pan ready; some fuel will spill when lines are opened.
• 🔋 Disconnect the negative battery cable using a 10mm socket and set it aside: Torque to 6 Nm (53 in-lbs) on reassembly.
• 🧼 Vacuum/clean the rear seat area so dirt cannot fall into the tank opening.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Relieve fuel pressure (reduce spray risk)

• Remove the fuel filler cap (at the fuel door) by hand to vent the tank.
• With the battery disconnected (from the prep step), pressure will bleed down; still treat lines as pressurized and open them slowly with shop rags wrapped around the connection.
• Open fuel lines slowly to avoid a splash.

Step 2: Remove the rear seat bottom cushion

• Slide the front seats forward for space.
• Use a trim removal tool (plastic) to pop the rear seat bottom cushion clips upward at the front edge.
• Lift the cushion out and set it aside.
• If your GLA has bolts instead of clips, remove them with a 10mm socket and reinstall later: Torque to 35 Nm (26 ft-lbs).

Step 3: Open the fuel pump access cover

• Locate the round/oval access panel on the floor under the rear seat (typically right side).
• Remove access cover fasteners using a Torx T20 bit or Torx T25 bit (varies).
• Lift the cover off carefully with a trim removal tool (plastic).
• Reinstall access cover screws later: Torque to 5 Nm (44 in-lbs).

Step 4: Clean the top of the pump module

• Use shop rags to wipe away dust and grit around the lock ring and fuel lines.
• If debris is heavy, wipe repeatedly rather than blowing it inward.
• Cleanliness here prevents repeat fuel pump failure.

Step 5: Disconnect the electrical connector

• Press the connector lock tab using a small flathead screwdriver (gently) and unplug the pump wiring.
• Inspect pins for corrosion or fuel contamination.

Step 6: Disconnect the fuel lines

• Place a catch pan (fuel-safe) and shop rags under the connections.
• Release the quick-connect(s) by depressing the locking tabs; use a pick tool only to help lift the lock (do not break it).
• Pull the line straight off the fitting while holding rags around it to catch fuel.
• Cap/cover the line ends with clean rags to keep dirt out.

Step 7: Remove the fuel pump lock ring

• Mark the current position of the lock ring and module with a small flathead screwdriver (a light scratch mark) so you can align it during install.
• Use a fuel pump lock ring wrench (specialty) with a 3/8" ratchet to turn the ring counterclockwise and remove it.
• If you do not have the ring wrench, use a brass punch (specialty) and small hammer to tap the ring counterclockwise. (Brass is softer and reduces spark risk versus steel.)

Step 8: Remove the fuel pump module

• Lift the module straight up slowly; tilt it as needed to clear the float arm (fuel level sender).
• Let fuel drain from the module into the catch pan (fuel-safe).
• Remove the old tank seal O-ring/gasket from the tank opening using a pick tool.

Step 9: Install the new seal and new module

• Install the new fuel pump module tank seal O-ring/gasket into the tank groove by hand. Make sure it sits flat and is not twisted.
• Lower the new module in, keeping the float arm from bending.
• Align the module orientation tabs/marks to your reference marks.

Step 10: Reinstall and tighten the lock ring

• Thread the lock ring on by hand first to avoid cross-threading.
• Tighten using the fuel pump lock ring wrench (specialty).
• Torque to 80 Nm (59 ft-lbs) if your ring wrench supports torque; otherwise tighten until the ring aligns with the factory alignment marks and the module is fully seated.
• If the ring feels “crunchy,” stop and re-seat.

Step 11: Reconnect fuel lines and electrical

• Push each fuel line straight onto its port until it clicks; tug gently to confirm it is locked.
• Reconnect the electrical connector until it clicks.
• If any retaining clip broke, replace it with the new fuel line retaining clips.

Step 12: Reinstall the access cover and rear seat

• Reinstall the access cover using a Torx T20 bit or Torx T25 bit: Torque to 5 Nm (44 in-lbs).
• Reinstall the rear seat cushion by aligning the hooks and pushing down firmly until the clips snap in.
• If your seat used bolts, tighten with a 10mm socket: Torque to 35 Nm (26 ft-lbs).

Step 13: Reconnect the battery

• Reconnect the negative battery terminal using a 10mm socket: Torque to 6 Nm (53 in-lbs).

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✅ After Repair

• 🔑 Turn ignition ON (do not start) for 10 seconds, then OFF; repeat 3 times to prime the fuel system.
• 🧻 Check the pump top and fuel line connections for any wetness or fuel smell before starting.
• 🚗 Start the engine and let it idle 2–3 minutes; re-check for leaks.
• 🧪 If a check engine light appears, scan for codes and clear after confirming no leaks.
• 🛑 If you see fuel seepage, shut the engine off immediately and re-seat the line/lock ring.

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💰 DIY vs Shop Cost

Shop Cost: $900-$1,600 (parts + labor)

DIY Cost: $250-$650 (parts only)

You Save: $650-$950 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-4 hours.

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🎯 Ready to get started?

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