Blagdon Pump AP50 Submersible - Manual (Page 5)

Pump Body
3.9
Remove governor housing and air motor as previously described.
Remove bolts (7) from volute (2) and lift pump body assembly
free.
3.10
Turn pump body over, lock impeller and remove nut (81) together
with impeller (3) from intermediate section (16).
3.11
Remove bolts (76) and withdraw bearing housing assembly (8)
from intermediate section (16).
3.12
Turn impeller shaft (74) and check for ease of movement and
quality of impeller bearing (11). Replace bearings as required.
3.13
To replace bearing (11), remove circlip (7) and withdraw impeller
shaft (74) from housing (8). Unscrew impeller nut (10) and
withdraw bearing (11).
3.14
Check impeller seals (75) and o-ring (6) for wear or damage,
replace as required. Ensure correct position of seals (75) so that
lips face the impeller.
3.15
If impeller is damaged or excessively worn, performance of the
pump will be reduced. When replacing, the impeller must be
adjusted to within 0.005" to 0.010" from the volute (2) internal
face for maximum efficiency. This is achieve by the addition or
subtraction of shims (4) & (5).
3.16 Re-assemble the pump as described above in reverse order. Ensure
all fittings are tight and secure before running the pump.