From the workshop · Indus blog
No SEO bait, no marketing fluff. Just practical writing about hydraulic systems from the people who specify, install and rebuild them every day.
A bubble under the cover looks like a manufacturing fault and normally is not. It is gas that got through the tube and could not get out through the cover — which tells you something specific about the fluid and the duty.
Where a hose failed is diagnostic. A burst within a hand’s width of the ferrule almost never means the hose was under-rated — it means something at that end was wrong, and replacing like for like will do it again.
JIC 9/16"-18 and ORFS 9/16"-18 are the same thread. They will assemble, and one of them will leak. Every designation and pitch we stock, grouped by family, with the collisions marked.
Measure the hose, hand over the number, and the assembly comes back too long. The figure a workshop needs is the distance between sealing faces — and the difference between that and what most people measure is the whole problem.
The line of text down the side of a hydraulic hose identifies it completely — grade, size, pressure, maker and often the date it was built. Here is how to read each element, and what to do when it has worn away.
A dash size is sixteenths of an inch of bore. Except on SAE 100R5, where −08 is a 10 mm bore rather than 12 mm — because R5 is sized on tube outside diameter. Here is the full conversion, and where it breaks.
Two of these pairings are real and printed on the same hose. Several of the equivalences circulating in the trade are not. Here is which is which, and what to do about the grades that have no counterpart.
R6 is rated 28 bar. R2AT is rated 400 bar. The higher number is fourteen times weaker. Here is what each SAE 100R designation actually specifies, and why the sequence tells you nothing about strength.
EN 857 1SC and 2SC bend to half the radius of standard braid at the same bore, in a smaller outside diameter, at the same or higher pressure. They remain the least-specified hose we stock.
Braided hose loses four fifths of its rating between quarter-inch and two-inch. Spiral hose holds flat. Past a certain bore the decision has already been made.
A grade is not a pressure. 2SN runs 400 bar at −04 and 80 bar at −32 — the same hose, an eightfold difference. Here is the full picture, size by size.
On a rebuild, recommissioning or cold-stack return, building every assembly at once produces a better machine and a better record than replacing hoses one failure at a time.
