DIY: D035 Coupling Maintenance
A brief education on the benefits of a DO35 coupling and a basic service of this style of hitch.
There was a time when virtually all van couplings were of the 50mm ball variety. The significant trend towards offroad and semi off road vans has seen many more offroad couplings adorning the front of A frames. And by far the most often spotted offroad hitch is the DO35 manufactured in Australia by Cruisemaster. It has gained great popularity due to its incredible articulation on two axes. This is achieved by using a pin which locks off in place of a tow ball and a mechanism with two pivot points.
The DO35 has many benefits, the most obvious being the coupling’s capability to cope with rough terrain. Being able to pivot the coupling also makes coupling and uncoupling a van on uneven ground much easier than a tow ball set up that tends to bind under load. And on an important safety note, the D035 can be a life saver in a van roll over event. A violent swaying van can unfortunately roll over under certain conditions. When connected to a conventional ball coupling, it is possible for the van to flip over the tow vehicle in the process as it has limited articulation. The infinite articulation of the DO35 means the van could completely roll over and not turn the car over.
The DO35 is more expensive than a ball coupling and a little more complex to service but there is a lot to like about it.
More detailed information on servicing D035 can be found on the Cruisemaster website.
Step by step guide
1. Apply degreaser all over the coupling
2. Scrub with a brush
3. A long bristle stiff brush is good for hard-to-reach spots
4. Clean up with a rag
5. Check that nuts securing coupling to A frame are tight
6. Apply firm lateral force to feel for any free play
7. Inspect the pin receiver for any irregular wear
8. Apply firm vertical force to feel for any free play
9. Check that the lock plate and lock button operate freely
10. Check that the pin engages in the receiver
11. Check the lock plate action again with the pin inserted
12. Check that the park brake mechanism operates freely
13. Grease the internal parts, applying a grease gun to the grease nipple
14. Pump with grease gun until “old grease” is cleared from system and remove
15. Lubricate the coupling latching mechanism with a light spray
16. Lubricate the parking brake lock mechanism with a light spray
17. Lubricate inside the park brake release with a light spray
18. Lubricate the pivot point with a light spray
19. Check that the rubber is in good condition on the latch release mechanism
20. Free play can be adjusted by tightening the slotted pin and nut. The first step is to remove the roll pin by tapping it out with a hammer
21. Tighten the slotted nut
22. Reinsert the roll pin
IF IN DOUBT, CONSULT A PROFESSIONAL
Improper maintenance can lead to injury, death or property damage. Maintenance work of this nature should only be undertaken by people with suitable competence. Information provided is general in nature, not comprehensive and should only be taken as a guide. Individual discretion must be exercised and persons undertaking described tasks do so completely at their own risk. Publishers and creators of this content accept no responsibility for loss or damage.
Thanks to Andrew Phillips and the team from the RV Repair Centre for their assistance.