Difficulty

Moderate

Steps

18

Time Required

                          30 minutes - 2 hours

Sections

4

  • Safety Precautions
  • 1 step
  • Oil Draining Procedure
  • 3 steps
  • Leg and Crankcase Separation
  • 8 steps
  • Bellows
  • 6 steps

Flags

0

  • BackWacker 4-Stroke Rammer model BS50-4AS (2019)

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Introduction

This model requires up to 0.7 liters of SAE 10W-40 oil to replace drained oil.

What you need

Step 1

              Disconnect the spark plug wire
  • 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.

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.

1024

Step 2

              Loosen the sight gauge
  • 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.

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.

Step 3

              Prepare a drain pan
  • Lay the device down horizontally with the oil sight gauge facing down.
  • Position a shallow oil drain pan underneath the sight gauge.

Lay the device down horizontally with the oil sight gauge facing down.

Position a shallow oil drain pan underneath the sight gauge.

Step 4

              Drain the oil
  • 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.

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.

Step 5

              Support the device
  • 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.

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.

Step 6

              Remove the leg assembly bolts
  • 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.

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.

Step 7

              Begin to separate the halves
  • Pull the leg assembly away from the rest of the device.
  • Ensure each half stays adequately supported.

Pull the leg assembly away from the rest of the device.

Ensure each half stays adequately supported.

Step 8

              Reveal the pin
  • Continue to separate the two halves by compressing the bellows until the nylon plug covering the piston pin is visible.

Continue to separate the two halves by compressing the bellows until the nylon plug covering the piston pin is visible.

Step 9

              Procedure tip
  • 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.

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.

Step 10

              Remove the pin
  • 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.

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.

Step 11

              Remove the leg assembly
  • Remove the leg assembly from the crankcase.

Remove the leg assembly from the crankcase.

Step 12

              Completely remove the pin
  • 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.

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.

Step 13

              Remove the hose clamps
  • Use a 13 mm socket or large flathead screwdriver to loosen the two hose clamp bolts securing the bellows to the leg assembly.

Use a 13 mm socket or large flathead screwdriver to loosen the two hose clamp bolts securing the bellows to the leg assembly.

Step 14

  • Lower the bottom hose clamp away from the bellows and let it rest at the base of the leg assembly.

Lower the bottom hose clamp away from the bellows and let it rest at the base of the leg assembly.

Step 15

  • Open the top hose clamp and pull it down, past the bellows, and let it rest at the base of the leg assembly.

Open the top hose clamp and pull it down, past the bellows, and let it rest at the base of the leg assembly.

Step 16

              Remove the bellows from the guide cylinder
  • Use a rubber mallet to tap the bellows down and off of the top of the guide cylinder.
  • Tap around the entire circumference of the bellows, pulling one edge down at a time.
  • During reassembly, use the rubber mallet to tap the bellows into place onto the lip on the cylinder.
  • Once loose, pull the bellows off of the lip on the guide cylinder.

Use a rubber mallet to tap the bellows down and off of the top of the guide cylinder.

Tap around the entire circumference of the bellows, pulling one edge down at a time.

During reassembly, use the rubber mallet to tap the bellows into place onto the lip on the cylinder.

Once loose, pull the bellows off of the lip on the guide cylinder.

Step 17

              Remove the guide cylinder
  • Lift up and remove the guide cylinder.

Lift up and remove the guide cylinder.

Step 18

              Remove the bellows
  • Use a rubber mallet to tap the bellows up and off of the top of the protective pipe.
  • Tap around the entire circumference of the bellows, pulling one edge up at a time.
  • During reassembly, use the rubber mallet to tap the bellows into place onto the lip on the pipe.
  • Once loose, pull the bellows off of the lip on the protective pipe.
  • Remove the bellows.

Use a rubber mallet to tap the bellows up and off of the top of the protective pipe.

Tap around the entire circumference of the bellows, pulling one edge up at a time.

During reassembly, use the rubber mallet to tap the bellows into place onto the lip on the pipe.

Once loose, pull the bellows off of the lip on the protective pipe.

Remove the bellows.

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.

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Author

                    Carsten Frauenheim

Member since: 03/10/2020

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