Hydraulic Piston Specification Example for Long-Haul Trucks: Drilled and Slotted
Hydraulic Piston Specification Example for Long-Haul Trucks: Drilled and Slotted
This is a worked specification for hydraulic piston in a drilled and slotted 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 drilled and slotted version exists because the duty cycle on long-haul trucks is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually warranty claims traced back to a single lot.

Example specification
| Item | Hydraulic Piston |
|---|---|
| Application | Long-Haul Trucks |
| Version | Drilled and Slotted |
| Base material | PU Leather |
| Controlled dimensions | 4 key dimensions, recorded per lot |
| Tolerance band | ±0.5 mm |
| Finish | as machined |
| 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 — PU Leather, 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
- die casting
- anodising
- shot blasting
- electroplating
- surface grinding
- injection moulding
Where this example applies
Programmes that run drilled and slotted most often specify this build for long-haul trucks. Related applications include assembly programmes, export programmes, camper conversions, dealership service, aftermarket retail.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 1.5 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
Can you match an existing sample?
Send a sample and we will reverse-engineer the specification, then produce a counter sample for approval before any bulk starts.
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the SAE J431-compliant build instead of a fresh interpretation.
How long does sampling take?
Samples leave the factory in 14 working days, and each revision round adds about 3 days once you have seen the first piece.
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.
Tell us the model, the fitment and the quantity and we will hold a production slot for you.



