I've spent way too much time trying to figure this out and could use some help.
Equipment
After changing all the seals (with Jack's 327 lube) and taking the pump apart over and over, there is a persistent leak from the bottom (housing gasket area) and surging (air noise).
On low speed, pump does not stay primed.
Diagnostics
Any advice appreciated.

Equipment
- 800 gallon in-ground hot tub
- Hayward Super Pump (SP2615X202S), unknown age. 2" plumbing reduced to 1.5" for filter and heater.
- No unions, so can't remove housing easily (and no space to add unions).
After changing all the seals (with Jack's 327 lube) and taking the pump apart over and over, there is a persistent leak from the bottom (housing gasket area) and surging (air noise).
On low speed, pump does not stay primed.
Diagnostics
- No obvious cracks in seal plate, impeller, or housing. Housing stays filled when pump is off.
- No water behind seal plate (shaft seal is probably fine)
- Housing gasket looks good
- Strainer gasket and drain plugs do not seem to leak under pressure.
- Pressure testing different sections using an air compressor:
- Returns lines hold pressure, no leaks (tested from pump housing inlet)
- Pump leaks water at 10+ psi, and air at 3+ psi, audibly, from that bottom area.
- Tried using dye (turmeric), looks like color stays on the housing side of the seal plate, but still can't tell where it leaks.
- Tried polishing the seal plate (1500 grit sandpaper), no change.
- Ground down the housing nuts as they protruded about 0.5mm, no change.
Any advice appreciated.
