Here's the insides of a failed HRX-426 drive gearbox...
Given the cost of a replacement box versus age of mower I had a go at a repair
To open remove retaining screws and carefully crack open with stanley blade + small hammer around seal
The main issue was it running dry due to seal failure and oil loss - leading to a thrust bearing melting into a plastic bush and offset wear on cone clutch gear
To fix
Ideally new thrust bearing was required - I elected to use old one as it ran free once all melted plastic was removed
The repair seems to work well after maybe 2 acres of mowing use.
Hope it helps someone!
Steve
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Given the cost of a replacement box versus age of mower I had a go at a repair
To open remove retaining screws and carefully crack open with stanley blade + small hammer around seal
The main issue was it running dry due to seal failure and oil loss - leading to a thrust bearing melting into a plastic bush and offset wear on cone clutch gear
To fix
- clean out and unpick thrust bearing from plastic
- insert an additional 1-2mm spacer washer to pack out melted plastic - to recentralise gear position and prevents clutch lever bottoming out
- flip the worn gear over
- clean shafts with wire wool around seal areas
- new seals 12x19x5mm (eBay)
- half fill with "Mill Gear 320 EP" (eBay) - no idea if this is correct oil but seemed a good choice
- new silicone sealant run around the groves
- close case and tighten screws - let it dry
Ideally new thrust bearing was required - I elected to use old one as it ran free once all melted plastic was removed
The repair seems to work well after maybe 2 acres of mowing use.
Hope it helps someone!
Steve
