Fruehauf Pro-Par Castellated Axle Nut
Fruehauf Pro-Par Castellated Axle Nut
$32.00
Fruehauf Pro-Par castellated axle nut suits parallel bearing trailer axle wheel ends, measuring 122mm across flats, 85mm ID and 29mm thick, so compare those dimensions and the castellated retention arrangement with the removed nut before fitting.
Part number AP4002.
Description
Overview
The Fruehauf Pro-Par castellated axle nut secures the wheel-end bearing adjustment on compatible parallel-bearing trailer axles. Its 122mm across-flats size, 85mm internal diameter, 29mm thickness and castellated profile distinguish this version from nearby axle-nut types.
Features
- 122mm across flats for matching the removed axle nut.
- 85mm internal diameter for the parallel-bearing spindle arrangement.
- 29mm overall thickness for dimensional comparison.
- Castellated profile for the matching mechanical retention setup.
Specifications and Materials
Product type: castellated trailer axle nut. Fitment family: Fruehauf Pro-Par parallel-bearing axle. Across flats: 122mm. Internal diameter: 85mm. Thickness: 29mm.
Part number: AP4002.
See the Fruehauf technical library for manufacturer trailer maintenance information
Compatibility and Fitment
Match the 122mm across-flats size, 85mm bore, 29mm thickness and castellated retention arrangement before fitting. The main mismatch risk is choosing a similar Fruehauf wheel-end nut with different dimensions or a different locking method.
The following cross-reference numbers identify verified equivalent or replacement parts for this exact application. Confirm the selection-critical fitment details against the part being replaced before fitting.
E-2550, 12-400, FL12.400, M10HN172, WT4002
Related Parts
Check the related service parts below against the trailer setup before ordering.
| Use | Part number | Part type |
|---|---|---|
| Washer to suit | AP4009 | Axle lock washer |
Compliance and Safety
Inspect the spindle, castellations and locking washer during wheel-end service. After bearing adjustment, secure the nut with the correct retention hardware and follow the axle-specific tightening and bearing-adjustment procedure.
Trailer Applications
Workshops fit the Fruehauf Pro-Par castellated axle nut during hub and bearing service where a parallel-bearing wheel end matches the 122mm A/F, 85mm bore and 29mm thickness.
Cross-reference and Suitability
This part cross-references to the following verified equivalent or replacement part numbers:
| E-2550 | 12-400 | FL12.400 |
| M10HN172 | WT4002 |
Why Choose ICS Trailers
Large axle nuts can look similar while differing in dimensions and locking arrangement, so compare the removed part before ordering. ICS Trailers can use old markings, photos, the 122mm across-flats measurement and wheel-end details to help narrow down the correct match.
- Support matching the lock washer and surrounding wheel-end service components.
- Help comparing replacement numbers when old markings differ between brands.
Browse more Axle Parts
Online prices apply to website orders only. In-store pricing may differ.






