HT25 - MAINTENANCE 91 1. Lay chain on ground with teeth down and pointed toward unit. 3. Back unit up until chain extends past head shaft about 1 ft (30.5 cm). 7. Pull rear end of chain over and about 10 in (26 cm) past tail roller. 8. Use hoist to pull front end of chain over head shaft sprocket. 9. Move chain down boom until chain connector pin and lock key can be installed. Install connector pin and lock key. 10. Tighten chain by pumping EPG into grease cylinder. 5. Lower boom to horizontal position. 4. Lower backfill blade to ground. p To install chain: 2. Start unit. 6. Stop engine. TRENCHER