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Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement

What you need

  1. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Disconnect the spark plug wire: step 1, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Disconnect the spark plug wire: step 1, image 2 of 2
    • Ensure the device is powered down and cool to the touch before starting your repair.

    • Firmly grip the base of the spark plug wire's connector and pull it away from the spark plug to disconnect it.

  2. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Loosen the sight gauge: step 2, image 1 of 1
    • Use a 1-1/16 inch socket to break loose the oil sight gauge near the bottom of the device.

    • Do not fully remove the oil sight gauge yet with the device in this upright position.

    • The oil sight gauge doubles as the oil drain and fill plug.

  3. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Prepare a drain pan: step 3, image 1 of 1
    • Lay the device down horizontally with the oil sight gauge facing down.

    • Position a shallow oil drain pan underneath the sight gauge.

  4. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Drain the oil: step 4, image 1 of 1
    • Remove the oil sight gauge.

    • Let the oil drain until drips are infrequent.

    • Replace and retighten the oil sight gauge.

    • This model requires 0.7 liters of SAE 10W-40 oil.

  5. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Support the device: step 5, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Support the device: step 5, image 2 of 2
    • Flip the device onto the work surface such that the motor and handles face up.

    • Place two separate blocks of wood underneath the seam between the leg assembly and crankcase.

    • Once the two halves separate, each side will need to be supported.

  6. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the leg assembly bolts: step 6, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the leg assembly bolts: step 6, image 2 of 2
    • Use an 8 mm hex key socket to remove the four bolts securing the leg's guiding cylinder to the crankcase.

    • You may need to use an impact driver or breaker bar to break these bolts loose.

    • During reassembly, ensure each bolt has its accompanying lock washer.

  7. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Begin to separate the halves: step 7, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Begin to separate the halves: step 7, image 2 of 2
    • Pull the leg assembly away from the rest of the device.

    • Ensure each half stays adequately supported.

  8. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Reveal the pin: step 8, image 1 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Reveal the pin: step 8, image 2 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Reveal the pin: step 8, image 3 of 3
    • Continue to separate the two halves by compressing the bellows until the nylon plug covering the piston pin is visible.

  9. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Procedure tip: step 9, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Procedure tip: step 9, image 2 of 2
    • Tip: To compress the bellows, insert a block of wood between the two halves and pivot the leg assembly off of the crankcase to compress the guide cylinder, revealing the pin.

  10. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the pin: step 10, image 1 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the pin: step 10, image 2 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the pin: step 10, image 3 of 3
    • Use an appropriately-sized punch and a ball-peen hammer to tap the pin out of its hole on the guide piston until it is no longer securing the connecting rod.

    • Once the piston and connecting rod are separated, the two halves become completely disconnected and will need to be adequately supported.

    • During reassembly, ensure that both nylon plugs are reinstalled and are flush with the surface of the guide piston.

  11. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the leg assembly: step 11, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the leg assembly: step 11, image 2 of 2
    • Remove the leg assembly from the crankcase.

  12. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Completely remove the pin: step 12, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Completely remove the pin: step 12, image 2 of 2
    • Use a punch and hammer to tap the pin out of the guide piston.

    • Once the pin is removed, the guide cylinder may spring up due to the compression of the bellows.

    • During reassembly, the bellows will need to be compressed to uncover the pin hole on the guide piston.

  13. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Support the device in an upright position: step 13, image 1 of 1
    • Use wood blocks to support the device on the work surface, motor facing up.

  14. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the engine guard: step 14, image 1 of 1
    • Use a 6 mm hex socket to remove the engine guard bolt securing the cable guide.

  15. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 15, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 15, image 2 of 2
    • Pull the cable guide away from the engine guard.

  16. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 16, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 16, image 2 of 2
    • Use a 6 mm hex socket to remove the three remaining bolts securing the engine guard: two on the outer edge and one near the crankcase.

  17. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 17, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 17, image 2 of 2
    • Remove the engine guard.

  18. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the motor nuts: step 18, image 1 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the motor nuts: step 18, image 2 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the motor nuts: step 18, image 3 of 3
    • Use a 13 mm wrench to remove the four nuts securing the motor to the crankcase, two on each side.

    • When removing the nuts, the crankcase bolts may also become unthreaded, preventing its accompanying nut from being removed. This is fine.

  19. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Move the muffler shroud: step 19, image 1 of 1
    • Use a 10 mm socket to remove the bolt securing the muffler shroud.

  20. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 20, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 20, image 2 of 2
    • Lower the muffler shroud away from the motor, down onto the crankcase.

    • Do not fully remove the muffler shroud.

  21. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Separate the motor from the crankcase: step 21, image 1 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Separate the motor from the crankcase: step 21, image 2 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Separate the motor from the crankcase: step 21, image 3 of 3
    • Tilt the device down onto its side, supporting both the crankcase and motor with blocks of wood.

    • The motor is loose from the crankcase, so support the motor as you lower the device down.

  22. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 22, image 1 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 22, image 2 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement: step 22, image 3 of 3
    • Hold the crankcase steady and pull the motor directly away from it.

    • Ensure each half stays adequately supported.

    • The motor is still attached to the rest of the device via various hoses and cables, so don't attempt to completely remove it.

  23. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the crankcase cover bolts: step 23, image 1 of 1
    • Use an 8 mm hex socket to remove the four bolts securing the crankcase cover.

  24. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Separate the crankcase cover from the crankcase: step 24, image 1 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Separate the crankcase cover from the crankcase: step 24, image 2 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Separate the crankcase cover from the crankcase: step 24, image 3 of 3
    • Any excess oil that did not drain out of the drain plug may leak out here. Be prepared with a shop rag or shop towel to catch any drips.

    • Insert a flathead screwdriver into one of the side gaps between the crankcase cover and the crankcase.

    • Twist the screwdriver to begin to pull the crankcase cover away from the crankcase.

    • Repeat for the opposite side gap, and repeat until the crankcase cover comes loose from the crankcase.

    • During reassembly, check that the crankcase cover O-ring is in good condition, and replace it if it is cracked or deformed.

  25. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the crankcase cover: step 25, image 1 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the crankcase cover: step 25, image 2 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the crankcase cover: step 25, image 3 of 3
    • Use your fingers to pull the crankcase cover off of the crankcase.

    • Feed the connecting rod around the clutch drum shaft and out through the crankcase cover hole.

    • During reassembly, feed the connecting rod around the clutch drum shaft and ensure the helical gears fully mesh.

  26. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the clutch drum snap ring: step 26, image 1 of 2 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the clutch drum snap ring: step 26, image 2 of 2
    • Use a pair of snap ring pliers to remove the snap ring securing the clutch drum to the crankcase bearing assembly.

    • During reassembly, ensure the clutch drum shaft is fully seated in the bearing assembly before attempting to reinstall the snap ring.

  27. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Tap out the clutch drum: step 27, image 1 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Tap out the clutch drum: step 27, image 2 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Tap out the clutch drum: step 27, image 3 of 3
    • Use a rubber mallet to tap the end of the clutch drum shaft through its hole on the top of the crankcase until it becomes loose enough to be moved by hand.

    • During reassembly, reseat the clutch drum into the bearing assembly by tapping it by the drum end.

    • Oil the new clutch drum shaft to ease installation.

  28. Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the clutch drum: step 28, image 1 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the clutch drum: step 28, image 2 of 3 Wacker 4-Stroke Rammer BS504AS REV 101 (2019) Clutch Drum Replacement, Remove the clutch drum: step 28, image 3 of 3
    • Push the clutch drum shaft with your fingers until it can be gripped from the top of the crankcase.

    • Since the motor is still connected to the crankcase, you may need to shift the motor's position on the wood blocks in order to fully remove the clutch drum.

    • Remove the clutch drum.

Conclusion

To reassemble your device, follow these instructions in reverse order.

After reassembly, tilt the device upright and check the oil level through the sight glass. The oil should cover 1/2 to 3/4 of the sight glass to be considered full. This model requires up to 0.7 liters of SAE 10W-40 oil.

Carsten Frauenheim

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