Guidelines for replacing the case gasket of axial-split pumps:
Check that the replacement gasket has correct thickness, pressure- temperature rating, and is asbestos-free.
Clean the case split surface (or parting flange) thoroughly with solvent, preferably a petroleum distillate-type.
On the top half-case, cover its entire split surface area with the gasket; the rough side facing outside.
Using a ball peen hammer, carefully cut out the gasket around the bolt holes area.
Spray coat thinly the rough side of the gasket with an adhesive such as 3M No. 77, or equivalent.
Position the gasket on the bottom half casing by carefully locating the cut outs with the bolt holes. Lightly sprinkle the gasket with dry powdered graphite.
Install the top half case on its bottom case. Tighten some nuts and bolts and let stand for about 10 minutes.
Remove the top half case.
Finish cutting away the gasket around the volute, waterway, and edges using a sharp knife. Be careful not to bevel the edges, and take precaution to prevent gasket debris from falling into the case passageways, while cutting.
Clean the entire gasket surface area before installing the upper half case.