Is there a limit to interlining?

Here's a no-nonsense breakdown of interlining limits in hydraulic hose assemblies:

1. Pressure Drop with Every Connection

Each coupling added disrupts smooth flow → turbulence builds → pressure drops.
Result: Your pump works harder, but actuators (cylinders/motors) move slower.
Rule of thumb: Avoid >2 couplings per hose run.

2. Leak Points Multiply

Every joint (coupling, adapter) introduces a potential leak.
Vibration amplifies risk: Loose fittings weep faster in linked assemblies.
Field reality: 3+ interlined joints = weekly leak checks.

3. Vibration Becomes Unmanageable

Hose weight + couplings = pendulum effect in mobile equipment.
Result: Joints shake loose, hoses whip against frames → abrasion holes.
Fix: Support brackets per coupling—but adds cost/complexity.

4. Bend Radius Nightmares

Couplings restrict flexibility: Tight corners kink hoses near joints.
Kinks: Block flow → overheat oil → burst hoses.
Workaround: Use 45° or 90° adapters → adds more connections.

5. When Interlining Might Be Acceptable

Scenario Max Couplings Why
Low-pressure (<1,000 PSI) 3–4 Less force = lower leak/blowout risk.
Static equipment 2–3 Minimal vibration → joints stay tight.
Temporary repairs 1 (emergency only) Never permanent—swap ASAP.

6. Red Flags to Stop Interlining

High shock/vibration (e.g., excavator boom): Use one hose, zero couplings.
Critical safety systems (brakes, steering): Never interline—single hose only.
Flow rates >20 GPM: Turbulence erodes fittings from inside out.