Loosen the body/bonnet joint stud/nuts and remove from body, loosen the eye bolt nuts, rotate the hand wheel in clockwise direction. Wedge will come down to closed position. Further rotate the hand wheel in same direction, bonnet assembly will rise in upward direction. Continue the same till spindle comes out of threaded portion of yoke sleeve. Lift the bonnet assembly to separate it from body. Hold the spindle portion above body with left hand and pull it upward by hammering gently on topside of body surface beyond gasket area. The spindle along with wedge will come out of body. Observe the condition of seat portion and interior portion of body.
Clean body interior portion and seat surface thoroughly with suitable cleaning liquid check up for any scratches on seat ring surfaces. Minor scratches should be removed by lapping with emery paste with the help of body seat lapping fixture.