Most DOT 4 labels on a cylinder box describe fluid compatibility, not an approval. Here is what EAC marking covers, where INMETRO fits, and which documents a buyer can check alone.
On a brake cylinder box, DOT 4 describes the fluid the seals are built for — not a certification of the part. The distinction matters because buyers routinely ask for a DOT certificate that does not exist for brake hydraulics.
DOT 4 is a fluid grade, not a part approval
DOT 3, DOT 4 and DOT 5.1 are grades of glycol-based brake fluid under FMVSS 116. A cylinder marked DOT 4 is telling you its seals are compatible with that fluid. There is no US federal approval programme for aftermarket brake cylinders as such, so a supplier who offers a DOT certificate for a cylinder is either describing the fluid or misunderstanding the rule.
The exception worth knowing: brake friction material has its own approval route under ECE R90 in Europe. That is a different product category, and it does not transfer to hydraulic cylinders.
What EAC marking actually covers
EAC is the conformity mark of the Eurasian Economic Union. Automotive components fall under the technical regulation for wheeled vehicles, TR CU 018/2011. Components supplied for assembly are certified as part of the vehicle type; the aftermarket route depends on the part and on the customs union's current list, which is why the answer changes between product categories and years.
The practical consequence for a buyer: ask for the certificate number and the scope it names, not just the mark on the box. A certificate that lists a factory and a part family is verifiable. A bare EAC logo is not.
| Mark on the box | What it actually certifies | Issued by | Can a buyer check it |
|---|---|---|---|
| DOT 4 | Fluid compatibility of the seals | Nobody — it is a fluid grade | Not applicable |
| EAC | Conformity with TR CU 018/2011 for the listed scope | Accredited body in the EAEU | Yes, by certificate number |
| INMETRO | Compliance for the Brazilian market | Accredited body in Brazil | Yes, by registration number |
| ISO 9001 | The factory's quality management system | Certification body | Yes, by certificate number and scope |
| IATF 16949 | The factory's automotive QMS | Certification body | Yes, by certificate number and scope |
Why the certificate usually belongs to the factory
ISO 9001 and IATF 16949 are plant-level certificates. A trading company does not hold them; the factory that produces the part does. This is why a serious supplier sends the certificate for the specific plant, with the scope naming the product family, rather than a company logo page.
Disben does not hold a company-level ISO 9001 or IATF 16949 certificate, and we do not describe ourselves as holding one. What we supply is the producing factory's certificate for the part number being quoted, on request, together with our own inspection records.
What you can verify without asking us
Three things are checkable in minutes. Trademark registrations can be looked up in the USPTO and CNIPA databases by number. A factory certificate can be checked with the issuing body, not with the supplier. And the OE number on the box can be cross-referenced in a public parts catalogue before the goods ship.
If a claim cannot survive one of those three checks, treat it as marketing text rather than a specification — and ask for the number behind it.