Cummins/Onan — Connecting Hydraulic Hoses
Installation · Hydraulic system
From a Cummins/Onan service manual covering: 5.5 HGJAA, 5.5 HGJAB, 5.5 HGJAC, 5.5 HGJAD, 5.5 HGJAE, 5.5 HGJAF, 6.5 HGJAA, 6.5 HGJAB, 6.5 HGJAC, 6.5 HGJAE, 6.5 HGJAF, 7.0 HGJAA…. Check it applies to your exact model before use.
Applies to: Cummins/Onan 5.5 HGJAD, Cummins/Onan 5.5 HGJAE, Cummins/Onan 6.5 HGJAE
Before you start
- The high pressure spray from a hydraulic line can penetrate the skin, leading to possible blood poisoning.
Procedure
- Provide enough slack in connected hoses to prevent strain due to pump movement.
- Support, restrain and protect hydraulic hose to prevent chaffing.
- Do not bend hose tighter than the hose manufacturer recommends.
- Use wide-sweep 90-degree fittings.
- Always use two wrenches when tightening hydraulic fittings.
- Install an SAE Class 4 filter (10 micron) in the system.
- Fill the reservoir and crank the engine with spark plug cables disconnected until oil reaches the pump.
- Purge air by running the genset a few seconds at a time until metallic noise stops.
Tools required
- Two wrenches Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- SAE Class 4 filter (10 micron)
Full service-parts list: Cummins/Onan 5.5 HGJAD →, Cummins/Onan 5.5 HGJAE →, Cummins/Onan 6.5 HGJAE →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.