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How to Replace a Qualcast Gear on a Classic Petrol 35s Lawnmower

Presumably due to the manufacturing cost, the Qualcast Classic Petrol 35s lawnmower uses plastic gears and over time these would perish.

If your lawnmower is not performing as it should and you can identify the cause as being faulty gears, then don’t even consider shipping the machine to a repair centre -  because this helpful guide will talk you through the simple process of replacing the gears on your lawnmower.

  What You Will Need:




  Step 1 - Safety Advice

Always make sure your lawnmower is switched off before you do any work. Just to be on the safe side either make sure the throttle is in the stop position or disengage the spark plug.

  Step 2 - Getting to the Drive System

There are three gears which we are going to guide you through, detailing the replacement process. To begin we first need to start by removing the side panel. This is held in place by four hex screws, so using a hex screwdriver or torx screwdriver you can now start to remove them.

With that panel off you will see the drive system - you will now need to remove the lower pulley cover, using a socket you can remove the bolt, and once that is removed you can then slide the belt off. Next you can remove the pulley and you’ll now see how the gears fit and work.

Please Note:

On the particular version of the 35s shown in the video the gear on the pulley and the smaller gear on the drive system tare actually the same spare part.

Continuing on now, you can begin to remove the cassette (the big rotary blade), which is held in place by two hex screws (Located on either side) - once these are removed you can simply slide the cassette out.

  Step 3 - Replacing the Cassette Gear

To replace the cassette gear you need to first secure the rotating blades, and to do this there are two options open to you:

1) You can hire the help of a friend, donning some heavy duty gloves they can just hold on to the cassette while you release the bolt using a socket.

2) Wedge an object (like a piece of wood) between the blade to hold them in place. The wood will help prevent damage to the cassette blades.

No matter which of the above two ways you choose, after deciding you will need to use a large socket to remove the gear and screw the new one back on.

  Step 4 - Pulley Gear

For the gear attached to the pulley, you’ll see it’s held in place by three pins and it’ll just slide off. Now it might be quite firmly attached and using a flat-head screwdriver, you can work your way round and lever it off. Once removed you can then pop the new one back on.

eSpares Top Tip:

Now if you’re having trouble you can separate the pulley from the gear and its plate, there are three screws that you can remove and will give you a bit more room to work.

  Step 5 - Lower Gear

Now to remove the final gear which is on the machine itself - you see that it is held in place by a clip, using a screwdriver you can lever it off. Once its come off the gear will now just slide away. You can then fit the new gear and then replace the clip back into position.

  Step 6 - Reassembly

With the gears all replaced you can now replace the cassette, refit the pulley and the pulley cover before finally securing the side cover back in place...and then you’re all done!

Well done, you have just successfully replaced the gears on your Qualcast Classic Petrol 35s lawnmower. For other helpful guides to assist in repairing or maintaining your lawnmower, don’t forget to you can check out our other articles in our advice centre.

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