Hydraulic Piston Specification Example for Trailer Axles: Premium Line
Hydraulic Piston Specification Example for Trailer Axles: Premium Line
This is a worked specification for hydraulic piston in a premium line programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The premium line version exists because the duty cycle on trailer axles is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually a fitment that looked right on paper and failed on the bench.

Example specification
| Item | Hydraulic Piston |
|---|---|
| Application | Trailer Axles |
| Version | Premium Line |
| Base material | Chromed Steel |
| Controlled dimensions | 4 key dimensions, recorded per lot |
| Tolerance band | ±0.5 mm |
| Finish | powder coated |
| MOQ | 500 pieces per specification |
| Sampling | 14 working days, 3 days per revision |
| Compliance | SAE J431 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Chromed Steel, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.

Processes involved
- heat treatment
- surface grinding
- rubber vulcanisation
- cold forging
- injection moulding
- shot blasting
Where this example applies
Programmes that run premium line most often specify this build for trailer axles. Related applications include rental motorcycles, light trucks, trailer axles, agricultural trailers, passenger cars.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 4.0 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
What happens if a lot fails inspection?
The lot is re-inspected against the golden sample, and replacement pieces ship on the next available booking at our cost.
What testing is included?
Standard lots ship with dimensional and hardness reports. SAE J431 documentation is issued with the shipment when your market requires it.
What is the minimum order quantity?
The standard MOQ is 500 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
How is packing specified?
Individual packing, inner box quantity and carton marking are confirmed at quotation stage so the cartons arrive ready for your warehouse.
Tell us the model, the fitment and the quantity and we will hold a production slot for you.



