Got it—let’s zero in on leaks at the hookup between a hydraulic torque wrench and its dedicated pump (typ. 700 bar / 10,000 psi systems with twin hoses and quick couplers). Below is a focused, do-now checklist that fixes 90% of cases and helps prevent a repeat.
Safety first
1.Stop the pump and depressurize the system: return valve open, trigger released, pressure gauge at 0.
2.Lockout/tagout. Wear eye/hand protection—pin-hole jets can inject fluid.
Quick checks (most common causes)
•Couplers not fully seated
• Wipe both male & female quick couplers clean.
• Pull back the sleeve, push together firmly until you feel/ hear a positive click.
• Tug test: they shouldn’t separate by hand.
•Damaged or missing O-rings in couplers
• Inspect the face O-rings and backup rings in both halves. Nicks, flat spots, swelling = replace.
• Use the exact size/compound (usually NBR for mineral oil; FKM for higher temp/chemicals).
•Dirty coupler check-balls/valves
• Grit prevents sealing. Flush with clean solvent, blow dry (low pressure), relube lightly with compatible oil.
•Brand/series mismatch
• Quick couplers must be the same series (e.g., ISO 7241-1 Series B) and brand-compatible. Mixed pairs often “fit” but leak.
•Over-bent or twisted hose near the ferrule
• If the hose is kinked/twisted right at the fitting, the seal is stressed and will seep. Re-route or replace the hose.
Inspect all leak points methodically
1.Pump ports
•NPT/NPTF threads: use proper hydraulic thread sealant (not PTFE tape shedding into the system).
•JIC 37° flare: no sealant—seal is metal-to-metal; check for scoring and correct torque.
•BSPP: use bonded/Dowty washer; inspect the washer.
•ORFS/metric OR: check face O-ring condition; replace if nicked.
2.Twin-line hose set
•Look for wetness under the strain reliefs and along the crimp—any seep = retire the hose.
•Verify working pressure rating ≥ 700 bar and that date codes aren’t past your replacement interval.
3.Tool swivel/rotation joint
•The 360° × 180° swivel on the wrench is a frequent culprit. Inspect its O-rings and backup rings; snug the gland per OEM spec.
4.Manifold/remote pendant connections (if fitted)
•Check all auxiliary fittings; vibration can loosen them—use a backup wrench to prevent side-load during tightening.
Reassemble the right way
•Clean, light oil film on O-rings.
•Support fittings with a backup wrench; tighten to spec (don’t over-torque).
•Route hoses with gentle radii (≥ 10× hose OD), no torsion. Add clamps to stop whipping/vibration.
Pressure test
1.Reconnect, cap any unused couplers.
2.Run the pump at low pressure first; watch every joint.
3.Step up to operating pressure while checking for weeps with a cardboard or mirror—never a finger.
4.If a joint weeps, mark it, depressurize, and correct. Don’t “snug under pressure.”
If it still leaks…
•Replace both halves of the quick coupler as a set. Wear is often complementary.
•Swap the hose set to rule out internal damage.
•Check oil type/temperature: wrong viscosity or overheated oil can thin out and reveal marginal seals.
•Verify relief pressure isn’t set above system rating.
•Check for micro-cracks in adapters/fittings (dye penetrant or magnifier).
Preventive habits
•Dust caps on all couplers—always.
•Keep a small O-ring kit matched to your system (couplers, swivel, ORFS).
•Pre-job connection checklist: clean → seat → tug test → route hoses → low-pressure leak check.
•Log hose/coupler service hours; replace on schedule, not just on failure.
If you tell me your coupler type (e.g., ISO B, JIC, ORFS) and where you see oil first (pump end, mid-hose, or wrench swivel), I can pinpoint the exact seal part numbers and tightening torques.
