Hydraulic Piston Specification Example for Delivery Vans: Sealed Unit
Hydraulic Piston Specification Example for Delivery Vans: Sealed Unit
This is a worked specification for hydraulic piston in a sealed unit 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 sealed unit version exists because the duty cycle on delivery vans is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually premature wear on the first batch.

Example specification
| Item | Hydraulic Piston |
|---|---|
| Application | Delivery Vans |
| Version | Sealed Unit |
| Base material | PVC Coated Fabric |
| Controlled dimensions | 3 key dimensions, recorded per lot |
| Tolerance band | ±0.1 mm |
| Finish | painted |
| MOQ | 200 pieces per specification |
| Sampling | 10 working days, 3 days per revision |
| Compliance | ISO 9001 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — PVC Coated Fabric, 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
- shot blasting
- laser cutting
- electroplating
- heat treatment
- die casting
- sintering
Where this example applies
Programmes that run sealed unit most often specify this build for delivery vans. Related applications include boat trailers, municipal fleets, fleet maintenance, camper conversions, workshop replacements.
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
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the ISO 9001-compliant build instead of a fresh interpretation.
How long does sampling take?
Samples leave the factory in 10 working days, and each revision round adds about 3 days once you have seen the first piece.
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.
What is the minimum order quantity?
The standard MOQ is 200 pieces per specification. Mixed sizes inside one shipment are accepted once the total reaches that figure.
Send the specification you are working to and we will confirm what we can match, what we would change and why.



