How to Replace the T3 & T5 Diaphragm?

Key Takeaways

The cup assembly and outer extension tube can be extremely difficult to separate, especially if they have never been taken apart before — considerable force may be needed, and a pool professional should be consulted if you are unsure.
When reassembling, ensure the two lugs on the diaphragm align correctly with the two gaps on the cup assembly — incorrect alignment will prevent the cleaner from working properly.
The diaphragm end of the engine unit must always face downward when pushed back into the body of the cleaner.
T3 and T5 models have a model-specific difference during reassembly — the T3 requires both upper and lower washers to be replaced, while the T5 requires the upper thrust washer to be reinstalled with the longer end facing downward.
Always refer to the exploded parts diagram for your specific model (T3 or T5) during disassembly and reassembly, as part numbers differ between the two cleaners.

In this article, we outline a step to step to replace your suction cleaner diaphragm in your T3 and T5 cleaners.

Unscrew the top lock nut (T5 Exploded Part 2, T3 Exploded Part 1).
Remove the T3/T5 engine unit from the body of the cleaner (T5 Exploded Part 1, T3 Exploded Part 2).
Unscrew and separate the cup assembly (T5 Exploded Part 8, T3 Exploded Part 5) from the outer extension tube (T5 part 7, T3 part 4). NOTE, this step can be incredibly difficult, especially if they have never been separated before. Considerable force might be needed to unscrew these 2 parts. If unsure please seek assistance from a pool professional.
Push the inner extension pipe and diaphragm (T5 parts 9 & 10, T3 parts 6 & 7) down through cup assembly.
Wriggle the diaphragm off the inner extension pipe.

Wriggle the diaphragm onto the inner extension pipe.
Pull the inner extension pipe through the cup assembly, with the diaphragm on the bottom. Ensure the 2 lugs on the diaphragm align with the 2 gaps on the cup assembly.
Screw the cup assembly & inner extension pipe onto the outer extension pipe.
Push the now reassembled engine unit back into the body of the cleaner, again with the diaphragm end towards the bottom.

4. a. If working on a Zodiac T3 pool cleaner, make sure to replace the upper and lower washer. (T3 Part 2)

4. b. If you’re working on a T5, make sure to replace the upper thrust washer, with the longer end facing downwards. (T5 part 3)

5. Re-screw the respective locking nuts.