The DO35 has been in production since 2009 and has been through four distinct generations, plus the AT35 that preceded it. They look broadly similar at a glance and they do not share service parts. Order a spindle bush kit for the wrong generation and it will not fit.
Worse, if you are in the United States, almost every search for DO35 service parts returns an Australian retailer. The information below is drawn from Cruisemaster's own identification sheet and maintenance documents, with the US torque figures called out where they differ.
Identify your generation first. Everything else follows from that.
Identify your coupling in about ten seconds
Look at the dust cap on top of the coupling. The word printed on it and its shape tell you almost everything.
| Generation | Years | Cap reads | Cap design | Other tells |
|---|---|---|---|---|
| DO35 V3Plus | June 2020 to current | Cruisemaster | Checklock Gen.2, square | Rear webbing, engraved markings, with or without handbrake |
| DO35 V3 | 2017 to 2020 | Hitchmaster | Checklock Gen.1, grey oval | Engraved or stickered markings, with or without handbrake |
| DO35 V2 | 2012 to 2017 | Hitchmaster | Checklock Gen.1, black oval | Gold SA5 coating, stickered markings |
| DO35 V1 | 2009 to 2012 | No cap at all | None, and no bumper | Two-hand locking mechanism, no handbrake, gold coating |
| AT35 | 2000 to 2009 | No cap | None | Drop pin design, no handbrake, gold coating |
The quick version:
- Square cap saying Cruisemaster means V3Plus, the current model.
- Oval cap saying Hitchmaster means V2 or V3, and the cap color separates them. Grey is V3, black is V2.
- No cap and a gold-colored body means V1 or AT35, both long out of production.
One extra check for V2 owners. Cruisemaster's V2 service documentation tells you to read the date stamp on the coupling, because units built before January 2015 use a 5mm sel-loc pin while later ones use 6mm. The spindle bush kit covers both, but you must fit the same size that came out. Check the pin before you order and again before you assemble.
Service parts by generation
These are Cruisemaster's own part numbers, taken from their maintenance instruction sheets.
DO35 V3 and V3Plus
| Part | Cruisemaster part number | Contents |
|---|---|---|
| Spindle bush kit | 18D-DO35-SPINDLE-BUSH-V3 |
2 spindle bushes, 1 sel-loc M6x40 |
| Lock repair assembly | 18D-DO35-REPAIR-V2-V3 |
Cover plate button assembly, slider, 2 slide springs, 3 sleeves, plunger spring, 3 pre-loctited M5x16 screws |
| Bumper and dust cover kit | 18D-DO35-CAP-BUMPER-V3 |
Bump cover and dust cover assembly, zip tie |
| Dust cap with lanyard | 18D-DO35-CAP-V3 |
Dust cover and lanyard assembly |
| Yoke and universal assembly | 18D-DO35.3-YOKE/UNI-V2-V3 |
Yoke and universal, 2 spindle bushes, sel-loc M6x40, nut |
| Tow pin O-ring | 18D-DO35-101 |
O-ring only |
DO35 V2
| Part | Cruisemaster part number | Contents |
|---|---|---|
| Spindle bush kit | 18D-DO35-SPINDLE-BUSH-V2 |
2 spindle bushes, sel-loc M5x40 and M6x40, grease sachet |
| Lock repair assembly | 18D-DO35-REPAIR-V2-V3 |
Same kit as V3, plus a washer plate in the V2 build |
| Bumper kit | 18D-DO35-BUMPER-V2 |
Bump cover and dust cover assembly, zip tie |
| Dust cap with lanyard | 18D-DO35-CAP-V2 |
Dust cover and lanyard assembly |
The V2 spindle bush comes in black and grey, and you must fit the same color that came out. Cruisemaster's instructions are explicit about this. Look before you dismantle.
The lock repair assembly is the one part shared across V2 and V3. Note that the V3 kit ships with an additional plate that is not used in a V3 build and should be discarded, so do not force it in trying to use every piece in the box.
Service intervals and the checks that matter
Cruisemaster recommends a thorough maintenance check every 10,000 km or 12 months, whichever comes first. That is roughly 6,000 miles.
Their published periodic maintenance list:
- Keep the tow pin and universal mating surfaces clean and lightly greased at all times. Grit between those surfaces is what wears a coupling out.
-
Check the tow pin O-ring and replace if needed. That is part
18D-DO35-101. - Grease the nipples regularly with multi-purpose lithium grease.
- Check all bolts for tightness.
- Adjust the slotted nut and pin periodically if the coupling head develops excessive play.
- Flush with clean water or an air hose if the locking mechanism will not open fully because of dirt ingress.
Leave the yoke pivot bolt alone. Cruisemaster specifies that it is only to be adjusted by one of their service agents. It is not a user adjustment.
Torque figures, including the US-specific ones
This is where American owners get caught out, because most of the documentation circulating online quotes the Australian figures.
| Fastener | Torque |
|---|---|
| Tow pin nut, US spec, 1 inch UNF | 530 Nm (390 lb-ft) |
| Tow pin nut, Australian spec, 7/8 inch | 440 Nm (325 lb-ft) |
| Coupling mounting bolts, M12 | 90 Nm (66 lb-ft) |
| Coupling mounting bolts, 1/2 inch | 100 Nm (74 lb-ft) |
| Handbrake mount bolts, pre-loctited | 35 Nm (25.8 lb-ft) |
| Lock assembly screws | 5 Nm |
530 Nm is a very high figure and it is not a guess-and-check fastener. Use a torque wrench that actually reaches it. You may need the supplied C-spanner to hold the tow pin while you tighten the nut.
After torquing the lock assembly screws to 5 Nm, Cruisemaster recommends marking the bolt heads so a later visual inspection immediately shows whether anything has backed off. It takes ten seconds and it turns a future inspection into a glance.
Replacing spindle bushes: the job most owners can do
Play in the coupling head almost always means spindle bushes, and this is the most approachable repair on the unit.
The good news: spindle bushes can be replaced without disassembling the front locking mechanism or the universal. If bushes are all you need, you do not have to take the coupling apart.
Tools: a 1-1/2 inch spanner or adjustable wrench, a hammer, and a punch matched to your pin, so 6mm for V3 and V3Plus and either 5mm or 6mm for V2 depending on the date stamp.
The sequence from Cruisemaster's sheets:
- Lift the handbrake handle to give maximum clearance.
- Tap out the sel-loc pin with the punch.
- Undo the nut and remove the yoke assembly.
- Remove and replace the poly bushes. Grease the outside of the bush and the internal bore so the spindle slides in easily. On a V2, line the bush groove up with the weld seam inside the housing. That alignment step is specific to the V2 and is easy to miss.
- Refit the yoke assembly and tighten the nut until it is firm but the yoke still rotates with some effort. Not locked solid, and not loose.
- Align the nut to the nearest cross-hole in the spindle and hammer the sel-loc pin home. Fit the same pin diameter that came out.
- Grease the coupling until grease squeezes out from the sides of the bushes, then check that the yoke still rotates properly.
Cruisemaster's documents carry an unambiguous warning on this work: failure to follow the directions may result in coupling failure. If you are not confident, this is a job for a service agent.
When to replace the whole coupling instead
Service kits fix wear. They do not fix damage or age.
Replace the coupling rather than servicing it if the body is cracked or deformed, if it has been used for vehicle recovery, if corrosion has gone past surface level into the structure, or if it is a V1 or AT35 still in service. Those last two are well past fifteen years old and are not supported by the current service kits at all.
Current replacements, US specification:
- Cruisemaster DO35, 3.5 tonne, no handbrake — the V3Plus, rated 3,500 kg (7,716 lb), SAE J684 Class 4, ships with a 1 inch US tow pin
- Cruisemaster DO35 with handbrake — same coupling with the integrated park brake lever, which you need if your trailer's brake cable runs to the coupling
- Cruisemaster DO45, 4.5 tonne, no handbrake — rated 4,500 kg (9,921 lb), takes a 1-1/4 inch tow pin
- Cruisemaster DO45 with handbrake
Check your tow tongue before ordering. The DO35 tow pin has a 1 inch (25.4mm) shank in US specification and mounts in a standard Class III or Class IV ball mount with a 1 inch ball hole. The DO45 needs 1-1/4 inch (32mm), which not every ball mount will take.
Spare tow pins for a second tow vehicle: DO35 tow pin kit, 1 inch UNF and DO45 tow pin kit. Both include the pin, cover and C-spanner.
If you need a service kit
The service kits listed above are Australian-supplied and are hard to source in the United States. If you have identified which generation you have and which kit you need, contact us with your generation, your date stamp if it is a V2, and the part number, and we will tell you what we can get and how long it will take.
Send the coupling's markings and a photo of the cap if you are unsure which generation you are looking at. Identification is the part that goes wrong most often, and it is much cheaper to check before ordering than after.