Zodiac Motor Block Shaft Pin Ø4 (Set of 5) - FreeRider FR200/FR1000/FR2000 iQ, Duo-X DX3000/DX4000/DX4050 iQ, Tornax TX20/TX30/TX35, OT15, FX18, CX20/CX35/CX40/CX50, Astralpool QB600/QB800, QG50 - R0657900
Zodiac Motor Block Shaft Pin Ø4 (Set of 5) - FreeRider FR200/FR1000/FR2000 iQ, Duo-X DX3000/DX4000/DX4050 iQ, Tornax TX20/TX30/TX35, OT15, FX18, CX20/CX35/CX40/CX50, Astralpool QB600/QB800, QG50 - R0657900 is temporarily out of stock and will ship as soon as it's available.
Associated with these models
- QB800
- QB600
- QG50
- FR2000 IQ
- FR1000 IQ
- FR200
- DX4050 IQ
- DX4000
- DX3000
- CX50
- CX40
- CX35 / CX35 TILE
- CX20 / CX20 TILE
- FX18 / FX18 TILE
- OT15 / OT15 TILE
- TX35 / TX35 TILE
- TX30
- TX20
Open a diagram to see where this part sits and what else is in the assembly.
Don't Guess - Ask Us!
Don't Guess - Ask Us!
Not sure if it’s the right part? Send us a message and a photo of what you’re replacing, or what you need, and we’ll help make sure you get the right part the first time.
Delivery and Shipping Info
Delivery and Shipping Info
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Warranty Information
Warranty Information
Zodiac Motor Block Shaft Pin Ø4 (Set of 5) - FreeRider FR200/FR1000...
Zodiac Motor Block Shaft Pin Ø4 (Set of 5) - FreeRider FR200/FR1000/FR2000 iQ, Duo-X DX3000/DX4000/DX4050 iQ, Tornax TX20/TX30/TX35, OT15, FX18, CX20/CX35/CX40/CX50, Astralpool QB600/QB800, QG50 - R0657900 is temporarily out of stock and will ship as soon as it's available.
Zodiac Motor Block Shaft Pin Ø4 (Set of 5) - FreeRider FR200/FR1000/FR2000 iQ, Duo-X DX3000/DX4000/DX4050 iQ, Tornax TX20/TX30/TX35, OT15, FX18, CX20/CX35/CX40/CX50, Astralpool QB600/QB800, QG50 - R0657900
Genuine Zodiac / Astralpool R0657900 - a set of five Ø4 shaft pins that lock the impeller to the motor block shaft. Small, cheap, and one of the most common causes of a cleaner that runs but has lost all suction.
- We keep these physically in stock for fast shipping or local pick-up, unlike most drop-shipping websites.
- Shipped from VIC, NSW, WA, QLD
Suits the following pool cleaners
- Zodiac FreeRider FR200, FR1000 iQ, FR2000 iQ
- Zodiac Duo-X DX3000, DX4000, DX4050 iQ
- Zodiac Tornax TX20, TX30, TX35
- Zodiac OT15, FX18
- Zodiac CX20, CX35, CX40, CX50
- Astralpool QB600, QB800, QG50
Part details
- Manufacturer part number: R0657900
- Supplied as: Set of 5
- Component: Motor block shaft pin, Ø4
- Related part: R0633200 - impeller CyclonX
- Genuine: Yes, genuine Zodiac / Astralpool spare part
When to replace them
- Motor runs but the cleaner produces no suction
- Impeller turns freely on the shaft by hand
- Pin is sheared, bent or has fallen out
- Fit a new pin whenever the impeller is removed or replaced
Fitment disclaimer
The models listed above are the applications we have been able to confirm. Zodiac, Astralpool and Polaris share components across several cleaner families and revise part numbers over time, so this list may not be exhaustive and your machine may use a different part. Always match the part number on your existing component, or contact us with photos plus your model and serial details, before ordering.
As with all products, these must be diagnosed and fitted by a qualified and experienced person.
Manufacturer Catalogues, Diagrams & Part Numbers
Need exploded views, spare part numbers, product numbers, diagrams, or more product information? See the manufacturer catalogues: Astralpool Catalogue 2026 | Zodiac Catalogue 2026
To the layperson, plumbing sizes and their names can be confusing due to the nominal sizes and naming conventions used.
This is not something we made up. Plumbers and manufacturers have used nominal (meaning ‘by name only’) sizing for decades.
Simply put, in plumbing, named sizes are often not the actual measurements of the pipe, fitting, or part. A PVC pipe called “50mm” or “2"” does not measure 50 mm anywhere. Instead, it follows nominal sizing, an internationally-standardised naming system.
Almost all fittings we use in the pool & spa industry use “pressure PVC” pipe & fittings. Do not confuse with “DWV” or other pipe & fittings and their names and sizes.
Use the Outside Diameter (OD) to check your pipe against fittings. Below is a quick reference for common spa & pool pipe sizes:
| Imperial Name | Metric Name | Pipe Diameter (OD) |
|---|---|---|
| 1/2" | 15mm | ~21.2–21.5 mm |
| 3/4" | 20mm | ~26.6–26.9 mm |
| 1" | 25 mm | ~33.4–33.7 mm |
| 1.5" | 40 mm | ~48.1–48.4 mm |
| 2" | 50 mm | ~60.2–60.8 mm |
| 2.5" | 65 mm | ~75.2–75.5 mm |
To reiterate, these are nominal sizes and are designed to fit matching fittings — not to measure what their name suggests. These are based on PVC Pressure Pipe AS/NZ 1477 Dimensions1.
- º Internal diameters vary slightly by manufacturer and class.
- 1 Not all pool/spa fittings match these dimensions exactly. Some do not follow Australian or international standards. Chinese spas may use proprietary fittings.
Understanding Plumbing Sizes & Nominal Measurements
Plumbing sizes can be confusing. PVC and many other pipe systems use nominal sizes—the size is a name, not the exact measured dimension. This convention is used across most pool and spa systems and other plumbing areas so that pipes and fittings remain compatible.
Why pipe sizes don’t match the measurements
The Nominal Pipe Size (NPS) system standardises pipe dimensions so that pipes, fittings, valves, and accessories interoperate.
Plumbers work with these nominal names every day, but DIYers can be tripped up if they try to match by a tape-measure alone.
How to Measure Pipe Correctly
-
Pipe size is identified by:
- The pipe’s Outside Diameter (OD).
- The fitting’s Inside Diameter (ID) (socket opening).
- Pipe Class / Schedule (e.g., Class 9, 12, 18 or Sch 40) relates to wall thickness and therefore the Internal Diameter (ID) and pressure rating.
- The outside diameter of a fitting is not useful (wall thickness varies by manufacturer).
Hose & Tube Dimensions
Common flexible hose sizes used in pool/spa systems (approximate IDs).
| Imperial Name | Metric Name | Inside Diameter (ID) |
|---|---|---|
| 3/8" | 9–10 mm | ~9 mm |
| 3/4" | 19 mm | ~19 mm |
BSP – British Standard Pipe Thread Sizes
BSP thread names are also nominal. The thread OD will not equal the nominal name.
| BSP Thread Size Naming | Outside Diameter (mm / inch) | TPI |
|---|---|---|
| 1/16" BSP | 7.7 mm / 0.304" | 28 |
| 1/8" BSP | 9.7 mm / 0.383" | 28 |
| 1/4" BSP | 13.16 mm / 0.518" | 19 |
| 3/8" BSP | 16.66 mm / 0.656" | 19 |
| 1/2" BSP / 15 mm | 20.99 mm / 0.825" | 14 |
| 5/8" BSP | 22.99 mm / 0.902" | 14 |
| 3/4" BSP / 20 mm | 26.44 mm / 1.041" | 14 |
| 7/8" BSP | 30.20 mm / 1.189" | 14 |
| 1" BSP / 25 mm | 33.25 mm / 1.309" | 11 |
| 1-1/4" BSP | 41.91 mm / 1.650" | 11 |
| 1-1/2" BSP / 40 mm | 47.80 mm / 1.882" | 11 |
| 2" BSP / 50 mm | 59.61 mm / 2.347" | 11 |
| 2-1/4" BSP | 65.71 mm / 2.587" | 11 |
| 2-1/2" BSP | 75.18 mm / 2.960" | 11 |
| 3" BSP | 87.88 mm / 3.460" | 11 |
| 4" BSP | 113.03 mm / 4.450" | 11 |
| 5" BSP | 138.43 mm / 5.450" | 11 |
| 6" BSP | 163.83 mm / 6.450" | 11 |
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R0657900
