Mantis Tiller 7940 (2017) Tine Shaft Roller Bearings Replacement

Written By: Tarun Thiruma

Comments: 1

Mantis Tiller 7940 (2017) Tine Shaft Roller Bearings Replacement

Difficulty

Moderate

Steps

Time Required

50 minutes - 1 hour

Introduction

Follow this guide to replace the two tine shaft roller bearings in the Mantis 7940 Tiller (2017).

For this guide, you will need to use a hammer to tap out certain components that are friction fit into place. In order to do this, you will need to find a way to brace the tiller in place so it doesn’t move around during the process. You can use a vice, or have someone else brace the part while you use the hammer.

You will need replacement lithium grease for this repair.

Tools

Parts

Step 1

Before starting any repair, ensure the ignition switch is in the "off" position, as shown.

Step 2

Use a 4 mm hex wrench to remove the bolt securing the spark plug housing.
Throughout this repair, keep track of each screw and make sure it goes back exactly where it came from.

Step 3

Remove the spark plug housing from the engine.

Step 4

Grab the rubber housing at the end of the spark plug wire.
Pull firmly to disconnect the wire from the spark plug.

Step 5

Twist and remove the knobs and acorn nuts from either side of the handle assembly.

Step 6

Remove the upper handle assembly from the lower handle assembly.
Do not pull the upper handle assembly too far from the rest of the tiller as it is still connected to the engine via the throttle cable.
Un-clip the throttle cable from the cable clips on either side of the handle assembly and set the upper handle assembly aside.

Step 7

Slide off and remove the tine retaining pin from the outer face of each tine assembly.
Caution: Take care when handling the sharp tines to prevent injuring yourself. Wear work gloves if necessary.
The tine assemblies can slide freely once their respective retention pins are removed. Do not let the assemblies fall off the tine shaft as this may damage them or result in injury.

Step 8

Slide off and remove both tine assemblies from the tine shaft.

Step 9

Use a Phillips #2 screwdriver to remove the four screws securing the gear housing cover.

Step 10

Remove the gear housing cover.

Step 11

Remove the gear housing cover gasket.
We suggest you replace this gasket during reassembly every time you open the worm gear housing to prevent any grease from leaking from the worm drive.
During reassembly, refill the worm gear housing with an adequate amount of lithium grease before installing the gasket and housing cover to ensure smooth operation of the worm drive.

Step 12

Use an adjustable wrench to turn the right half (in the orientation pictured) of the tine shaft clockwise, as shown.
Continue to turn the shaft clockwise until it is unthreaded from the worm gear inside the housing.

Step 13

Use a dead blow hammer to tap the right half of the tine shaft towards the worm housing until it can be removed.
If the shaft won't budge with the dead blow hammer, you can try using a ball-peen hammer instead.

we tried, the gear spins but feels like it keeps catching on something? im doing everything as its telling me but yet, the shaft wont budge an inch..

RUBEN -

Step 14

Slide the tine shaft assembly out from the left side of the worm housing and remove it.

Step 15

Slide the worm gear up out of the worm gear housing about 1 cm.
Use a flat head screwdriver to separate the right worm gear thrust washer from the worm gear.

Step 16

Remove the worm gear and left worm gear thrust washer from the worm housing.
Separate the left thrust washer from the worm gear.
During reassembly, insert the worm gear into the housing before inserting the thrust washers next to it on either side. All three will be aligned properly once the tine shaft is reinserted.

Step 17

Remove the right worm gear thrust washer from the worm gear housing.

Step 18

Slide off the left-hand tine shaft roller bearing assembly from the tine shaft.

Step 19

Separate the tine shaft roller bearing from the assembly and remove it.
It is recommended that you also replace the bearing seal next to the roller bearing to prevent any grease from leaking out of the worm gear housing.

Step 20

Insert a properly sized bushing driver into the left (as in pictured orientation) tine shaft aperture.
Use a dead blow hammer to gradually tap out the right-hand tine shaft roller bearing assembly from the gear housing.
If the bearing won't budge with the dead blow hammer, you can try using a ball-peen hammer instead.

Step 21

Remove the right-hand tine shaft roller bearing assembly.
Separate the tine shaft roller bearing from the assembly and remove it.
It is recommended that you also replace the bearing seal next to the roller bearing to prevent any grease from leaking out of the worm gear housing.

Step 22

During reassembly, In order to reinstall the right-hand tine shaft roller bearing assembly, use the bushing driver to tap in the roller bearing, then bearing seal from the right side of the housing until there is enough space to insert the bearing seal retainer.
If the bearing won't budge with the dead blow hammer, you can try using a ball-peen hammer instead.

Conclusion

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

Author

Tarun Thiruma

Member since: 20/11/19

36553 Reputation

Mantis Tiller 7940 (2017) Tine Shaft Roller Bearings Replacement

Introduction

Tools

Parts

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