Installing a coupling to a trailer can seem a simple task. Trailparts have a few tips and recommendations to ensure you and your load reach your destination safely. The following installation guide can be used as a reference installing all Trailparts trailer couplings, both braked and non-braked.

Before installing your coupling, check the ball size and weight rating on your intended tow vehicles towbar. All towbars have a specified rating / load capacity. Towballs are available in two sizes, 1 7/8" (47.6mm) or 50mm. If you require flexibility to use either towball size, Autofit is available for a range of trailer setups; non-braked, electric braked, and hydraulic braked up to 3500kg (check specs).

Positioning the coupling is also important to the trailers structural integrity and connection strength. The coupling body must be positioned so that the likelihood of inadvertent damage to any component while in use is minimized.

Note: For Hygo Coupling installation specifications please refer to the Hygo mkII Installation Guide.

trailer coupling

Coupling Mount Torques

Coupling Bolt Size G 8.8 G 10.9
Non Braked M10 45 ft/lb 60 Nm 60 ft/lb 80 Nm
Braked M12 75 ft/lb 100 Nm 90 ft/lb 120 Nm

Note: All coupling bolts must be fastened using Nylon insert nuts (Nyloc). A minimum of three thread must be exposed past the nut when fully tightened.

Greasing / Lubrication

Properly greased couplings are the key to long life and safe use!

  • Tow ball connections should be greased because metal on metal causes screeching noises and premature wear. If the towball or inner coupling surface (tongue) wear becomes extreme the coupling can dislodge itself from the tow vehicle while in travel.
  • Braked couplings should be greased on actuator load bearing and moving surfaces using the grease nipples located on the coupling body.

Over-ride Coupling - Which Master Cylinder do I use?

Trailparts low profile master cylinders are available in two sizes. Both sizes have the option of including the Autoback reversing solenoid, eliminating the need to get out of your vehicle and lock out the hydraulic actuator.

  • 3/4" Master Cylinder, suits trailers fitted with a single braked axle.
  • 1" Master Cylinder, suits trailers fitted with two or three braked axles.