b'SIGHT GLASSES - SLSG SERIES 7 . 0 R E A S S E M B LY1.Re-assemble in reverse order of disassembly.2. Refer Appendix A for bonnet bolt re-tightening procedure and torques.8 . 0 PREVENTATIVE MAINTENANCESight glasses require virtually no maintenance but ensure during normal functioning the flow indicator is not hammering or slamming.9 . 0 L E A K A G E A C R O S S G A S K E TShould any bonnet gasket leaks occur, tighten the bolts/nuts & studs (refer Diagram 1, Appendix A). If leakage still persists, the bonnet gasket should be changed, refer to 10.1 below.1 0 . 0 M A J O R M A I N T E N A N C EOnly an expert valve re-conditioner should attempt the following major maintenance/repairs.Sight glasses require very little maintenance. Generally, the only viable repairs are replacement of bonnet gasket. However, see below for further extraordinary repairs.Always replace the bonnet gasket whenever a sight glass is disassembled. Gasket seating surfaces should be scraped clean (avoid radial marks). Bonnet bolts should be tightened in a diagonal pattern at several different increasing torque settings in accordance with the recommended torque value (see Diagram 1, Appendix A).10.1 GASKET REPLACEMENT1.Disassemble all cover bolts and nuts (or unscrew if a screwed bonnet). 2. The bonnet should be easy to remove without the aid of a mechanical lifting device. Gently break the seal with a lever, gradually lifting the bonnet flange at intervals 360 around the bonnet. 3. Clean gasket surface areas, replace gasket and refit bonnet as detailed in 10.0 above.10.2 SIGHT GLASS INTERNALS DISASSEMBLY INSPECTION AND REPAIR1.Check that the (where applicable) hinge pin, nut and sight flow indicator are in good condition and firmly connected. Replace damaged parts as necessary.2. Lift and remove the sight flow indicator assembly. Movement should be free and not hindered by any 8 Australian Pipeline Valve - Installation, Operation and Maintenance Manual'