Cruisemaster DO35 V3Plus Coupling Quick Guide
The Cruisemaster DO35 V3Plus is a 3.5 tonne all-terrain coupling engineered for safe, articulated off-road towing. This guide covers hitching, safety checks and basic maintenance as fitted to your Rhinomax camper. For full installation, torque settings and warranty terms, download the complete PDF below.
⚙️ Basic Operation – Hitching Up
Follow these steps every time you hitch your Rhinomax to the DO35 tow pin.
1. Prepare Tow Pin & Coupling
Remove the tow pin cover. Ensure the tow pin and the DO35 universal are free of dirt, sand and stones and are lightly greased to prevent wear.
2. Set Coupling to UNLOCKED
Push down on the red Lock Button while sliding the locking plate rearward towards the button. When correctly unlocked, the viewing port is clear and the plate protrudes at the rear.
3. Lower Onto Tow Pin
Use the jockey wheel to raise the trailer so the coupling is above the pin. Align over the tow pin and lower until the universal fully seats on the pin and the pin is visible through the locating/locking port.
4. Lock & Secure
Press the red Lock Button again to slide the locking plate forward into the LOCKED position. Confirm the pin protrudes through the port, then fit the Check-Lock dust cap until it gives an audible “snap”. Fit safety chains and breakaway cable.
🛡 Unhitching & Safety Checks
Safe disconnection and key safety rules for your DO35 V3Plus.
Unhitching Procedure
- Chock the trailer wheels and apply the handbrake.
- Remove the Check-Lock dust cap from the tow pin.
- Set the coupling to UNLOCKED (press Lock Button and slide plate rearward).
- Use the jockey wheel to raise the trailer until the coupling lifts cleanly off the pin.
- Refit the tow pin cover to keep dust and moisture out.
Critical Safety Rules
- Keep hands and fingers clear of the coupling when hitching/unhitching.
- Always attach safety chains during coupling and uncoupling.
- Do not use the tow pin or coupling for recovery or snatch strap attachment.
- Ensure recommended drawbar weight is between 50kg and 350kg for stable towing.
Using a Weight Distribution Hitch (WDH)
- The DO35 can be used with WDH systems if coupling movement is not obstructed.
- Maximum downward load prior to tensioning bars: 350kg.
- Check clearances in tight reversing or off-road articulation scenarios.
WDH adaptor kits are available from Cruisemaster for improved clearance with some systems.
🔧 Troubleshooting & Common Issues
Quick checks to resolve most hitching and coupling problems.
Coupling Won’t Drop Fully Onto Pin
- Ensure the coupling is in the UNLOCKED position (viewing port clear).
- Check for dirt, stones or rust on the tow pin or inside the universal – clean & re-grease.
- Adjust jockey wheel so the coupling is directly above the pin and not binding on an angle.
Locking Plate Won’t Engage / Feels Sticky
- Flush the locking mechanism with clean water or compressed air to remove dust and grit.
- Lightly grease moving surfaces as per manual instructions.
- If still stiff, have the coupling inspected by a Cruisemaster-approved repairer.
Excessive Free Play or Clunking
- Check that the tow pin nut is correctly torqued to specification and has not loosened.
- Inspect the universal and tow pin for visible wear.
- The slotted nut & pin on the yoke may need adjustment if the yoke is loose in the housing – this must be performed by a competent technician or Cruisemaster-approved repairer.
Check-Lock Cap Hard to Fit
- Confirm the coupling is fully locked and the pin is correctly protruding through the port.
- Inspect the cap and O-ring for damage; replace if worn.
- Ensure there’s no mud or debris in the dust cap or around the tow pin.
🛠 Preventative Maintenance
Regular maintenance ensures long service life and smooth articulation off-road.
Clean & Grease Mating Surfaces
Keep the tow pin and universal socket clean and lightly greased at all times. Wipe off built-up dirt and reapply multipurpose lithium grease as needed.
Check O-Ring & Dust Cap
Inspect the tow pin O-ring for cracking or wear and replace if necessary (size: BS115 O-ring). Always use the Gen.2 Check-Lock dust cap when not towing to protect the pin.
Annual Inspection
Every 10,000 km or 12 months, grease the nipple, check all mounting bolts for correct torque, and have the yoke pivot and slotted nut checked by a competent repairer if any play is detected.