| Vehicle identity | Complete 17-character VIN, including the model-year position | Vehicle identification plate, registration document, or approved service record | The VIN must contain 17 characters and must match the vehicle being repaired. Do not use a shortened chassis number. | 17-character VIN transcribed exactly; no missing or substituted characters | Pass |
| Model year confirmation | Model year, production date, and trailer or vehicle series | VIN decoding record plus the original build sheet | Confirm the 2026 application from the build record. Registration year alone is not proof of model year. | Model year: 2026; production date: recorded separately | Verify |
| Gross Vehicle Weight Rating | GVWR or technically permissible maximum laden mass | Certification label, type-approval document, or OEM specification sheet | The selected suspension must not reduce the vehicle’s certified GVWR or axle rating. | GVWR: 3,500 kg shown on the certification label | Pass |
| Axle load requirement | Front or rear GAWR, or the applicable trailer axle rating | Axle label, type plate, axle certificate, or approved technical record | Compare the spring assembly’s certified capacity with the load carried by that axle. Never use total GVWR as a substitute for axle load. | Rated axle load: 1,750 kg; required capacity per spring: 875 kg before any specified design margin | Calculate |
| Spring load rating | Rated capacity of one spring and of the complete axle set | Stamped spring record, supplier certificate, or approved engineering drawing | Capacity, ride height, and stress limits must agree with the original specification. A higher nominal capacity is not automatically compatible. | Pair capacity must support the certified axle load and the documented suspension design | Certify |
| Spring type | Single-leaf, multi-leaf, slipper, eye-to-eye, or other documented construction | OEM parts record and physical inspection | The replacement must use the same approved spring architecture unless an engineering change has been documented. | Multi-leaf spring with front eye and rear eye recorded in the build specification | Match |
| Eye-to-eye length | Unloaded center-to-center distance between spring eyes | OEM drawing or measurement from an undamaged reference spring | Measure with the spring unloaded. Do not measure a flattened or permanently deformed spring as the design length. | Measured unloaded length: 760 mm; confirm against the approved drawing tolerance | Measure |
| Spring width | Leaf width at the mounting and clamp areas | OEM drawing and calibrated vernier or steel rule | Width must match the hanger, bushing, U-bolt, and clamp hardware. A small width difference can prevent correct seating. | Leaf width: 60 mm; hardware opening must accommodate the documented width | Measure |
| Eye and bushing dimensions | Eye inner diameter, bushing outer diameter, and bushing length | Parts drawing, service manual, and measured replacement hardware | The bushing must fit the hanger bolt without looseness, binding, or forced installation. Record dimensions in millimetres. | Eye inner diameter: 30 mm; bushing length and bolt size still require confirmation | Check |
| Camber and arch | Free camber or unloaded arch height | OEM drawing or controlled measurement on a level surface | Compare the unloaded profile with the approved design. A visibly flatter replacement may change ride height and axle alignment. | Free camber: recorded in the engineering drawing; do not estimate from photographs | Compare |
| Center bolt and locating feature | Center-bolt diameter, head orientation, and axle-seat location | Axle drawing and spring assembly inspection | The locating feature must seat correctly in the axle pad. Incorrect orientation can shift axle position or damage the assembly. | Center bolt: 16 mm; head direction and seat depth confirmed before installation | Confirm |
| Fastener compatibility | U-bolt diameter, length, thread condition, nuts, washers, and torque specification | Vehicle service documentation and fastener specification | Use the documented fastener grade and tightening procedure. Replace stretched, corroded, or previously overloaded U-bolts. | New U-bolts required; final torque must come from the approved service record | Do Not Reuse |
| Load certification | Certificate identifying capacity, test basis, part dimensions, and traceability | Current supplier certificate or engineering conformity record | The certificate must identify the exact spring specification. A generic catalogue rating without traceability is insufficient for final approval. | Certificate number, revision, tested capacity, and material traceability recorded | Require |
| Installation outcome | Ride height, axle alignment, clearance, and post-installation inspection | Workshop measurement sheet and roadworthiness inspection | Both sides must be installed as the approved pair where required. Check tire clearance, brake-line clearance, and abnormal lean before use. | Left/right ride height difference within the documented service tolerance | Inspect |
