Compressor Hoses – Models 574987405 & 574987802

Two oil-resistant rubber hoses engineered for rotary screw compressor hydraulic and pneumatic circuits. 574987405 is specified as an intake / air-filter-to-inlet-valve hose on 18.5–37 kW frames (GA37-class), while 574987802 serves the larger 37–55 kW frames (GA55-class) as an oil-return or separator-outlet hose. Both use NBR inner tube + fiber-reinforced braid + CPE/CSM outer cover, rated for continuous oil-mist and high-vibration service.

Key Features

• 574987405: ~Φ32–40 mm ID × ~300–400 mm length, 16 bar working, 64 bar burst, 120 °C max — intake-side or low-pressure oil-return

  
  

• 574987802: ~Φ40–50 mm ID × ~400–550 mm length, 16 bar working, 64 bar burst, 120 °C max — separator outlet / oil-return on larger frames

  
  

• Inner tube: NBR (oil + aerosol resistant, ≤120 °C)

  
  

• Reinforcement: 1-ply polyamide/nylon braid + cotton insert (anti-kink, anti-collapse under suction)

  
  

• Outer cover: CPE/CSM (ozone, UV, oil-spray resistant, black)

  
  

• Swaged metal inserts + stainless-steel clamp grooves on both ends

  
  

• Media: mineral oil + air mist (separator outlet), or ambient air (intake side for 574987405)

  
  

Technical Specifications

Application Guidance

574987405 – Connects the panel-type air-filter housing to the inlet valve on 18.5–37 kW screw compressors. The NBR inner + fiber braid absorbs airend vibration so the filter housing and inlet valve aren't tugged by the pulsating suction. Also cross-used as a small-bore oil-return line on the same frames (check media tag — oil-return trim uses the same hose with different end inserts).

574987802 – Lives at the separator outlet elbow or the oil-return from the cooler on 37–55 kW frames. The larger ID handles the full oil-flow circulation (3–5 L/min at 65–85 °C) plus the 7–13 bar air pushing through the MPV. The CPE outer shrugs off the oil-mist spray that coats the separator housing exterior.

⚠️ Confirm media before fitting: intake-side hoses carry air only (NBR is fine); separator-outlet hoses carry oil + air at 7–13 bar — use the oil-rated trim. Swapping an intake hose into the separator outlet position will soften the NBR inner within 2000 h.

Installation Notes

1. Shut down compressor, vent receiver and oil circuit to 0 bar, lock out electrics.

   
   

2. Loosen stainless-steel clamps (typical 8 mm hex), slide hose off the stub. Inspect stub for burrs or corrosion — sharp edges will chew the new inner tube.

   
   

3. Push new hose fully home onto both stubs — the swaged insert should bottom against the shoulder.

   
   

4. Tighten clamps to 8–10 N·m (clamp manufacturer spec), alternating sides so the hose doesn't twist. Over-torque cracks the clamp band; under-torque lets it creep off under vibration.

   
   

5. For intake hose (574987405): leave ~15–20 mm slack so airend vibration doesn't tension the hose — a taut hose tears at the clamp groove within 4000 h.

   
   

6. Restart, load to full pressure, soap-test both clamp joints — bubbles = loose clamp or mis-seated hose.

   
   

7. Log hours at install; inspect at every 2000 h service — cracks on the outer cover or stiff/NBR hardening means replacement due.

   
   

Failure Symptoms

• Intake hose (574987405) split → un-metered air suck-in past the filter, higher dust load on airend, whistling at the clamp

  
  

• Separator-outlet hose (574987802) weep → oil spray on the enclosure floor, separator ΔP climbs (oil loss → lower sep efficiency), high oil carryover at the receiver

  
  

Quality

• Inner tube NBR compounded for 80–120 °C continuous oil-mist (PAO & ester synthetic compatible)

  
  

• Burst tested ≥ 4× working pressure per batch

  
  

• Ozone resistance ≥ 72 h @ 40 °C / 50 pphm (ASTM D1149 reference)

  
  

• Clamp grooves machined to ISO 6162 / SAE J518 face-port tolerance

  
  

Ordering

Specify 574987405 (intake / minor oil-return, ~32–40 mm ID, 18.5–37 kW frames) or 574987802 (separator outlet / oil-return, ~40–50 mm ID, 37–55 kW frames) with quantity. Confirm media (air-only vs. oil+air) and end-insert style against your machine's hose routing diagram — GA37 vs. GA55 stub diameters differ by ~5–8 mm.

All dimensions nominal; confirm ID, length, and media rating against your compressor's parts book before ordering. Stainless-steel clamps sold separately on some kits — verify if your unit reuses existing clamps or requires new.