The Cruisemaster DO35 is one of the toughest off-road hitches (couplings) you can fit — but like any articulating component, it relies on regular maintenance to keep moving freely and locking safely. A few minutes of care after each trip prevents premature wear, binding, and the grinding that comes from a dry or grit-packed mechanism. Here's how to look after yours.
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How the DO35 works (and why maintenance matters)
The DO35 is a drop-on pin coupling (DO = "Drop-On"): it drops over a fixed tow pin and locks with a positive two-stage latch, while polyurethane bushes let it articulate on three axes over rough terrain. Those poly bushes, the tow pin, and the locking mechanism are the parts that wear — so they're the parts your maintenance routine should focus on.
Greasing your DO35
Keeping the coupling greased is the single most important maintenance task. A well-greased DO35 articulates smoothly and quietly; a dry one wears its bushes quickly and can grind or bind over bumps.
- Use the grease points on the coupling body with a grease gun and a quality EP (extreme-pressure) grease, working grease through until it appears at the articulation joint.
- Grease regularly — follow the interval in your Cruisemaster user guide. As a practical rule, re-grease every few thousand kilometres, before a big trip, and any time articulation starts to feel notchy or stiff.
- Always re-grease after water crossings and after dusty, muddy, or beach (salt) travel, which wash out or contaminate grease fastest.
Cleaning after every off-road trip
Grit is the enemy of any articulating coupling. After dusty or muddy travel, wipe the coupling down and clear debris from around the pin and lock. After salt or water exposure, rinse with fresh water, dry, and re-grease so moisture can't sit in the mechanism. Keep the patented Checklock dust cap fitted whenever you're not hitched — it keeps grit out of the lock and doubles as a safety check, since it only fits when the lock is correctly engaged.
Inspect the poly bushes
The polyurethane bushes are wear items. Periodically check for excessive play, cracking, or a sloppy feel in the articulation. Some lateral movement is normal; significant play or clunking means the bushes (or pin) are worn and due for replacement. The bushes can be serviced without replacing the whole coupling body — a key reason the DO35 lasts.
Check the tow pin for wear
The tow pin takes the load every time you tow, so inspect it for scoring, flat spots, or visible wear, especially before long or remote trips. A worn pin should be replaced rather than nursed along. Keep a spare on hand — it's also what lets you tow with a second vehicle:
- DO35 Tow Pin Kit (1" UNF) — pin, nut, and split pin to refresh a worn DO35 pin.
- Towing the bigger DO45? Grab the matching DO45 Tow Pin Kit — the pins are not interchangeable.
Check mounting bolts and the lock
Off-road vibration can settle bolted joints. Periodically confirm the coupling's mounting bolts are tight to the spec in your fitting instructions, and before every tow, do a quick safety check: engage the two-stage lock, confirm the Checklock cap seats (proving the lock is engaged), and give the coupling a firm pull to confirm it's secure.
Quick maintenance checklist
- After every trip: wipe down, clear grit from pin and lock, refit dust cap.
- After water / salt / heavy dust: rinse, dry, and re-grease.
- Every few thousand km (per your user guide): grease the articulation joint.
- Periodically: inspect poly bushes and tow pin for wear; check mounting bolt torque.
- Before every tow: confirm two-stage lock engages and dust cap seats.
When to replace parts
Replace the tow pin if it's scored or worn, the poly bushes if articulation develops noticeable play or clunking, and the dust cap if it's damaged or no longer seats properly. Staying ahead of wear is far cheaper than a coupling failure on a remote track.
Need parts? Shop the full Cruisemaster range — DO35 and DO45 couplings and genuine tow pin kits, in stock and shipping from Upland, CA. Always follow the torque figures and service intervals in your official Cruisemaster user guide, and have any work you're unsure about checked by a qualified fitter.