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Selection Guide
How to choose the right hydraulic hose
A blown hose on a job site in Jamaica or a vacuum truck stuck in a depot in Valley Stream is a truck down, a contract at risk and a bad phone call. Most of those failures were not inevitable. They came from the wrong hose in the wrong application.
- Work through STAMP before ordering anything. Size, Temperature, Application, Media, Pressure.
- Match bore to flow rate, not to the fitting thread. They are different dimensions.
- Working pressure, not burst pressure. Burst is roughly four times working and is a test figure, not a target.
- Surge spikes can exceed working pressure by half again during rapid valve actuation.
- Minimum bend radius is a real limit. Forcing a tighter curve kinks the tube and creates the failure point.
- Crimped fittings are not reusable. The ferrule deformed once and will not do it again reliably.
The methodFive variables, worked in order
The industry uses STAMP because skipping any one of the five gets you a hose that fails for a reason you did not consider. A hose that handles the pressure but not the fluid temperature fails just as fast as one that is undersized.
Fleet supervisors who have been at this a while have seen every version of what happens when one gets skipped. The rest of this walks each in turn.
S is for sizeMatch the bore to flow, not to the fitting
Inside diameter sets flow velocity. Too small and you get pressure drop and heat. Too large and the hose is unwieldy and costs more than it needs to.
Most shops target a fluid velocity in the region of 10 to 15 feet per second on pressure lines at flows under 25 GPM. Return and suction lines run slower, which is why a return line is often a size up from the pressure line beside it.
Do not size the hose from the fitting thread. A 3/4 inch NPT fitting tells you nothing about the bore the system needs. Pull the original, measure the inside diameter directly, and start there.
Dash sizes
Hydraulic sizing is quoted in dash numbers, which are sixteenths of an inch of bore. Worth knowing because it is the language the counter works in.
| Dash | Bore | Dash | Bore |
|---|---|---|---|
| -4 | 1/4 inch | -12 | 3/4 inch |
| -6 | 3/8 inch | -16 | 1 inch |
| -8 | 1/2 inch | -20 | 1-1/4 inch |
| -10 | 5/8 inch | -24 | 1-1/2 inch |
One warning: dash numbers on AN performance fittings do not follow the same relationship. If you are working on a build rather than a machine, check which system you are in. See high performance hoses.
T is for temperatureCount what is outside the hose too
Hydraulic systems run hot. Petroleum based fluid in a working system typically sits somewhere between 100 and 180 degrees Fahrenheit, and high cycle or high load systems push beyond that.
The part people miss is ambient. A hose routed behind a diesel block or along an exhaust on a pump truck is absorbing radiant heat from outside as well as carrying hot fluid inside. Standard SAE hydraulic hose ratings assume the hose is not sitting against a constant heat source.
Where it is, you need a heat resistant cover or protective sleeving. Get this wrong and you will replace the same hose repeatedly while wondering why that spot keeps failing. Sleeving on hose accessories and fittings.
A is for applicationRouting kills more hose than pressure does
A hose correctly rated for pressure and temperature still fails early if the installation makes it flex the wrong way.
Every hydraulic hose has a minimum bend radius, the tightest curve it can take without internal damage. Force it tighter and the tube kinks or cracks, which restricts flow and creates a failure point under pressure. The bend radius is published for every hose and it is not advisory.
- Keep bends away from the fitting. A hose should leave the ferrule straight for a short distance before it starts to curve.
- Allow for length change. Hose shortens under pressure, so a line fitted taut will pull at the crimp every cycle.
- Clamp anything that moves. Unrestrained hose finds something to rub against and abrades through the cover.
- Cross at right angles. Where two hoses touch, crossing at ninety degrees wears far less than running parallel and rubbing.
On vacuum trucks, roll-offs and pump systems, routing is usually an afterthought until something chafes through on a frame rail. Anything running near a hot surface, a moving component or a metal edge needs an abrasion cover or sleeving. On service vehicles working Jamaica and Brooklyn, where equipment takes daily abuse, that is not optional.
M is for mediaThe fluid decides the tube
Standard hydraulic hose is built for petroleum based fluid. Run something else and the inner tube may not be compatible.
- Water glycol and fire resistant fluids need a tube rated for them. Standard nitrile is not always suitable.
- Biodegradable fluids in environmentally sensitive work have their own compatibility list.
- Phosphate esters attack compounds that petroleum fluid never touches.
The bigger risk in a mixed fleet is confusion. Fuel hose, air line, coolant hose and hydraulic line all look similar from the outside. Put a fuel rated hose into a hydraulic circuit and you get premature tube degradation, or worse, a contamination problem that costs far more than the hose did. We confirm the media before cutting anything on custom hose fabrication.
P is for pressureWorking, burst and the one in between
Two numbers get printed on hose and a third one is what actually kills assemblies.
Working pressure is the maximum continuous operating pressure the hose is rated for. Burst pressure is where it fails on a test rig, typically around four times working under SAE standards. Burst is a manufacturing benchmark, not a design target, and quoting it as capability is how people end up under-specified.
Neither accounts for surge. Hydraulic systems generate momentary spikes during rapid valve actuation or load shift that can exceed working pressure by fifty percent or more. If your system works at 3,000 psi and spikes to 4,500, a hose rated to 3,000 is outside its design envelope every time the machine cycles.
Above 3,000 psi, wire braid or spiral construction is the standard rather than an upgrade. And on any high cycle system, specify for the spike rather than the steady state.
ConstructionSAE ratings and what they mean
| Rating | Construction | Typically for |
|---|---|---|
| 100R1 | Single wire braid | Moderate pressure general hydraulics |
| 100R2 | Double wire braid | Higher pressure, the fleet workhorse |
| 100R7 / R8 | Thermoplastic, fibre reinforced | Light, flexible, mobile equipment and twin line |
| 100R12 / R13 / R15 | Four or six spiral wire | High pressure and high impulse, 5,000 psi and up |
| 100R14 | PTFE tube, stainless braid | Extreme temperature and aggressive chemicals |
When replacing, match the SAE rating to the original or go up. Never substitute down, even if the pressure numbers look close, because the rating carries impulse and temperature performance as well as pressure. Full range on hydraulic hoses.
EndsThreads are not interchangeable
Getting the hose right then pairing it with the wrong fitting is the most common mistake in field repair. Thread type, size, sealing method and orientation all matter independently.
| Type | Seals on | Note |
|---|---|---|
| JIC | 37 degree flare cone | Metal to metal on the cone. No tape, ever. |
| NPT | The tapered thread itself | The one that does want sealant. |
| ORFS | Flat face with an O-ring | Excellent for vibration. Check the O-ring every time. |
| BSP | Parallel or tapered, bonded seal | Looks like NPT and is not. Different thread angle. |
A JIC male will start onto some ORFS females, and it will never seal, because the geometry is different. If a connection needs force to start, stop. See hydraulic fittings and adapters.
A crimped or swaged fitting deformed permanently when it was installed. Once cut off, that geometry is spent and it cannot be reliably re-crimped. Field reusable fittings exist, but they have to be specified as reusable from the start. See hydraulic hose crimping.
SafetyNever find a leak with your hand
A pinhole leak is a hypodermic needle
People routinely run a hand along a line suspected of leaking, see nothing, and raise the pressure to bring the leak out. At the moment the fingers reach the pinhole, fluid goes through the skin as if injected.
The entry wound looks trivial. The damage underneath is not, and hydraulic fluid is toxic in tissue. Hand surgeons treat these as surgical emergencies, and delay is what turns them into amputations. A peer-reviewed review of United States emergency department data covering 2012 to 2021 examined more than 15,000 high-pressure injection injuries of the hand.
Find leaks with a piece of cardboard held at arm's length, not with skin. Depressurise before working on anything, and remember that hydraulic circuits hold pockets of pressure after the pump stops. Industry safety guidance such as this toolbox talk on high-pressure injection injuries sets out the technique.
If it happens, go straight to a hospital emergency department, say the words high-pressure injection injury, and take the fluid safety data sheet. Receiving staff may not recognise it from the wound, because there is barely a wound to see.
Faster than a part numberBring the old hose in
If a hose is a non-standard length, has an unusual fitting combination, or came off equipment nobody documents any more, duplicating the failed one is quicker and more reliable than specifying from scratch.
From a broken hose we measure the bore, identify the construction, confirm both end fittings and the orientation between them, and build an exact replacement, usually while you wait. That beats hunting a part number that may no longer exist.
It is the normal sequence for our walk-in customers: a truck goes down in Nassau County, the operator pulls the hose and drives it in. More on hydraulic hose assemblies and emergency hose repair.
Proudly serving Long Island since 1964
Sixty years building hydraulic assemblies for Long Island fleets and contractors, from our counters in Nassau County and Suffolk County, within reach of Queens and Brooklyn.
There is a reason operators drive in rather than order. Research into near-me search behaviour found that roughly 76 percent of people who run a "near me" search visit a business within 24 hours, citing Think with Google. A machine down this morning is not a shipping problem.
Common Questions
Hydraulic hose FAQ
It classifies the hose by construction and pressure capability. 100R1 is single wire braid for moderate pressure, 100R2 is double wire braid for higher. Spiral types such as 100R12 and R13 handle high pressure and high impulse work. Match the original rating or go up, never substitute down, because the rating carries impulse and temperature performance as well as pressure.
Size, Temperature, Application, Media and Pressure, the five variables that between them determine hose selection. Work through all five before ordering. Skipping any one gets you a hose that fails for a reason you did not consider.
If the hose body is genuinely intact, with no cracking, no abrasion through the cover and no kinking, and the failure is only at the connection, the fitting may be the issue. But if the hose has been under stress where it meets the fitting, the tube can be compromised while looking fine outside. Replacing a fitting on a compromised hose is a short term fix that usually fails again.
The hose is the flexible tube with its reinforcement. An assembly is the finished part: cut to length, fittings crimped on both ends, tested and ready to install. When a line fails, an assembly is what you actually need.
In most cases no. Crimped and swaged fittings deform permanently during installation to make a pressure-tight joint, and once removed that geometry cannot be reliably reproduced. Field reusable fittings exist but have to be specified as reusable from the start.
In heavy fleet and industrial use, typically a few years, though high cycle systems such as vacuum truck hydraulics wear faster than occasional-use equipment. The bigger factor is whether the hose suited the application from the start. A mismatched hose can fail in weeks. A correctly specified one rarely causes trouble.
The tightest curve a hose can hold without internal damage. It is published for every hose and it is a limit, not a suggestion. Forcing a tighter bend kinks or cracks the tube, restricting flow and creating a failure point. Keep bends away from the fittings, and let the hose leave the ferrule straight before it curves.
Never with your hand. A pinhole leak under pressure injects fluid through skin like a needle, and the entry wound looks trivial while the damage underneath is severe. Use a piece of cardboard held at arm's length. Depressurise first, and remember circuits hold pockets of pressure after the pump stops. If injection happens, go straight to an emergency department and say the words high-pressure injection injury.
Ask The Counter
Not sure of the spec?
Send the machine, the working pressure and a photo of both ends. Somebody who builds these daily will tell you exactly what it takes.
Built While You Wait
Pull it, drive it in, drive out with it
Two Long Island counters, six days a week. 1/8 inch to 2 inch, up to 6,000 psi, crimped on calibrated equipment.