Hydraulic Trailer Brakes: Top 12 Kits & Buying Tips 2025
Hunting for a hydraulic brake kit that actually fits your trailer and stops it on a dime? The 12 kits below are the pick of 2025—ranked by stopping power, corrosion resistance and value—so you can match the right discs or drums to your boat, caravan, horse float or digger transporter without second-guessing axle ratings or stud patterns.
You’ll also pick up the essentials: how hydraulic trailer brakes work, what makes discs outperform drums at the boat ramp, which couplings keep NZTA inspectors happy, and the easiest way to bleed a fresh line. Because coastal salt, steep passes and local compliance rules change the game here, every kit featured is either on the shelf at Action Outdoors in Auckland or ships to New Zealand minus the paperwork hassle. Ready to roll? The shortlist starts below.
1. Action Outdoors Trojan 10" Stainless Disc Brake Kit (Best All-Round Choice for NZ Trailers)
After a fit-and-forget brake that shrugs off salt? Trojan’s all-stainless 10-inch disc kit delivers.
Key specifications & what’s in the box
260 mm vented rotor, 316-grade caliper, 2 t axle rating. Box: hubs, pads, brackets, marine grease, plus either rubber or braided hoses.
Why it tops our 2025 list
NZ warehouse stock—no duty—and Trojan’s 5-year corrosion warranty. NZTA VIRM ticked. Stops roughly 20 % shorter than drum sets.
Ideal users & trailer types
Ideal for 6 m fibreglass boats, tandem jet-ski trailers and car carriers under 3.5 t, using 45 mm four-stud flanges.
Price range & where to buy
Budget NZ$799–$899; bundle with surge actuator and DOT 4 at ActionOutdoors.kiwi or the Auckland shop.
2. AL-KO 12" Marine Grade Stainless Disc Kit (High Corrosion Resistance)
Regular boat-ramp dunkings demand more than zinc; AL-KO’s 12-inch full-stainless disc kit stays shiny season after season.
Key specifications
- 305 mm rotor / hub, 304 stainless casting
- Floating twin-piston caliper, 2 500 kg axle
- 5 × 114.3 mm studs, double-lip marine seals
Stand-out features
- Lab-rated 1 000-hour salt-spray life, bearings pre-torqued
Best for
- Charter and coastal boat trailers dunked daily
Things to note
- Needs AL-KO flange or adapter; top-end price tag
3. Trailparts Gator 2K Hydraulic Drum Brake Kit (Budget-Friendly Workhorse)
Need a no-frills stopper that keeps the accountant happy? Trailparts’ Gator 2 K drum set slots straight onto most 45 mm square axles and costs less to run than it does to fill the ute.
Key specifications
- 10" cast drums
- 200 × 50 mm shoes
- 2 000 kg axle rating
- Zinc-plated backing plates
Strengths
- External adjuster—no drum removal
- Cheap shoes stocked NZ-wide
Ideal applications
- Builder box trailers
- Rubbish-run rigs
- Farm quad carriers
Drawbacks
- Needs freshwater rinse
- Slightly longer stops downhill
4. Kodiak Vent-Pro Ceramic-Coated Disc Kit (Long Life, Low Noise)
Vent-Pro runs cool and quiet, the ceramic coat fighting rust from beach ramps to frosty mountain passes.
Key specifications
- 10.5" Dacromet vented rotor
- Ceramic pads, 3 500 kg axle rating
- 5 × 114.3 mm stud pattern
Why choose Kodiak
Vented channels shed heat 15 % faster, and ceramic friction material stays whisper-quiet for roughly 30 000 km.
Suitable trailers
- Tandem caravans
- Horse floats on alpine routes
Watch-outs
Dacromet chips; dab exposed spots with zinc spray to keep corrosion at bay.
5. Dexter E-Z Lube 10K Drum Kit (Heavy Tow Capacity)
Shifting mini-excavators or loaded scaffold racks? The Dexter 10K drum kit is specced for serious mass, yet service takes minutes thanks to its grease-through hub cap—no messy bearing pull-apart on the job site.
Key specifications
- 12" × 2" cast-iron drums
- Axle capacity 4 535 kg (10 000 lb)
- E-Z Lube grease zerk integrated in hub cap
Highlights
- Self-adjusting shoes halve routine tweak time
- Optional park-brake lever ticks NZ WOF box for >1 000 kg ATM
Best for
- Machinery plant trailers
- Portable digger transporters
- Heavy trade or rental loads
6. Trojan Hydraulic Drum & Mechanical Park Brake Combo Kit
Tight space on a small trailer? Trojan’s 9-inch combo drum adds a park brake without clutter.
Key specifications
- 9" cast-iron drum, bonded shoes
- Built-in mechanical park lever
- 1 500 kg axle rating
Benefits
- Combines service & park brake—fewer parts
- Cable and clips supplied
Best fit
- Small campers, single-axle caravans, tiny houses
Limitations
- Not for tandem axles over 2 000 kg
7. Titan Dico 13" Integral Rotor Kit with Stainless Caliper
When heat-cracked rotors keep ruining pads, this integral hub/rotor setup from Titan Dico provides a tougher alternative for hydraulic trailer brakes pushing the 3 500 kg mark.
Key specifications
- One-piece 330 mm hub/rotor casting
- Twin-piston stainless caliper with anti-rattle spring
- Axle rating: 3 500 kg, 6 × 139.7 mm studs
Selling points
- Integral design minimises run-out, extending pad life
- Stainless pistons resist seizing after winter lay-up
- Large thermal mass tames fade on long descents
Considerations
- Heavier unsprung weight can nibble at fuel economy
- Check 15"-plus wheel clearance before ordering
8. CM Trailer Parts HD Disc Brake Kit 2750–3500 kg
CM’s heavy-duty discs shrug off corrugations and mud, perfect for rural work.
Key specifications
- 286 mm (2 750 kg) or 305 mm (3 500 kg) rotor sizes
- Zinc or stainless finish
- Suits 4-stud 45 mm & 5-stud 50 mm flanges
Advantages
- Nationwide spares; pads and seals at most farm stores
- Shim kit supplied for exact caliper spacing
Ideal for
- Stock floats, horse boxes, gravel-road machinery trailers
9. Knott UK Hydraulic Drum Kit with Sealed Bearings
Knott’s sealed-bearing drum kit delivers Euro reliability with zero-grease servicing—perfect for busy hire fleets or anyone clocking serious kilometres.
Key specifications
- 250 × 40 mm drum (10")
- Sealed cartridge bearings, 3 000 kg axle rating
- 5 × 112 mm studs supplied with M12 nuts
Why we like it
Factory-packed bearings run 30 000 km before replacement, and cam-lever adjusters give perfectly even braking every stop.
Considerations
Metric pattern—double-check wheels fit older NZ trailers before ordering.
10. AL-KO IQ7 Electric-Hydraulic Drum Kit (Hybrid Ease)
AL-KO’s IQ7 kit bolts on hydraulic bite and an electric brain. It teams a 1 000 psi actuator with two 10-in drums (1 600 kg/axle) and an on-board breakaway battery.
Key specs
- IQ7 actuator, self-check LED
- 10" × 2¼" drum assemblies
Pros
- No in-car brake controller
- Meets NZTA >2 t breakaway rule
Cons
- 12 kg actuator crowds draw-bar
- Battery needs yearly test
11. Trailparts Stainless Cupro-Nickel Brake Line & Disc Kit
Upgrading crusted steel lines during a disc swap? Trailparts bundles a 2 500 kg stainless disc set with 6 m of pre-flared 3⁄16" cupro-nickel tube—one box sorts stopping and plumbing.
Key specifications
- 2 500 kg axle rating
- 6 m cupro-nickel line, stainless JIC fittings
Differentiators
- Cupro-nickel bends by hand, resists salt 60 % better than steel
- Pre-flared ends cut fit-up time to 30 min
Ideal for
DIY refits where seized lines risk WOF.
12. Titan Dico 20K Heavy-Duty Drum Brake Kit (For Big Loads)
Moving earthmovers or high-side tippers? Titan’s 20 K drum set is the go-to when your axle tips the scales close to nine tonnes yet you still need reliable hydraulic trailer brakes that pass every COF inspection.
Key specifications
- 12.25" × 3.375" drum, 9 t axle rating, 50 mm studs, heavy-duty bearings
Strengths
- Cast-steel shoes and 70 mm magnet cylinders survive endless downhill braking heat
Watch outs
- Needs 16" wheels; each corner adds 12 kg, trimming available payload
13. Buying Guide: Choosing the Right Hydraulic Trailer Brake Kit
A shiny new brake kit is pointless if the specs don’t marry up with your trailer’s weight, environment and legal obligations. The checkpoints below slice through the jargon so you can hit “buy now” with confidence.
Trailer weight, ATM & axle rating
ATM = tare weight + max payload and is stamped on your rego label. Pick a kit that carries at least 10 % more than that figure. The quick-reference table helps:
| Trailer set-up | Typical ATM (kg) | Minimum kit rating* |
|---|---|---|
| Single axle | ≤ 1 500 | 1 600 |
| Tandem axle | 1 500–3 500 | 3 500 |
| Tri-axle | 3 500–9 000 | 9 000 |
*Adds 10 % safety headroom.
Drum vs disc: performance, cost & maintenance
Discs shed heat and water faster, cut fade on alpine descents and resist salt better, but pads and rotors cost more. Drums are cheaper and dust-proof for farm use, yet need more adjustment and rinse discipline.
Rotor & caliper materials: cast iron, Dacromet, stainless
Cast iron is cheapest but loves rust. Dacromet (zinc-aluminium) buys 3–5 salt seasons. Full 304/316 stainless shrugs off decade-long dunking—ideal for coastal storage. Don’t mix stainless rotors with steel calipers or galvanic corrosion will follow.
Couplings & actuators: override, surge, electric-hydraulic
Under 2 000 kg ATM, simple override surge couplings are legal. Above that, NZTA demands a powered breakaway system: electric-hydraulic units like AL-KO IQ7 deliver 1 000 psi on cue and tick the compliance box. Check tow-ball size—1 ⅞″ or 50 mm—or use a Duofit.
Stud pattern, bearings & axle flanges
Measure stud pitch circle diameter (PCD) before ordering: common NZ patterns are 5 × 114.3, 6 × 139.7 and 5 × 150 (LandCruiser). Read bearing numbers (e.g. L68149/L68110) on your old hub and match them to the kit. Most light-duty axles use a 45 mm four-bolt flange; heavy units jump to 50 mm five-bolt.
Compliance & certification
WOF trailers (< 3 500 kg) need brakes on at least one axle; COF rigs (> 3 500 kg) require every axle braked and a certified modification plate if you switch systems. Keep invoices and manufacturer datasheets—inspectors may ask for proof the kit meets NZTA VIRM standards.
14. Installation & Maintenance Essentials
Even the best kit can turn sketchy if fitted poorly. The micro-guide below keeps the job safe, tidy and inside a weekend. Allow extra time for seized fasteners.
Tools & workspace checklist
- Axle stands & chocks
- Torque wrench (135 Nm)
- 14 mm flare spanner
- DOT 4 fluid & bleed bottle
- Marine grease & thread-locker
- Grommets & zip ties
Step-by-step install overview
- Jack trailer, support, remove wheels
- Unbolt hubs, clean flange
- Pack bearings, slide rotor, fit nut
- Bolt caliper, torque, back-off 0.5 mm
- Route lines above springs, clip 300 mm
- Join to actuator, fill fluid
Bleeding & bedding-in brakes
Bleed with a vac-pump or helper until clear fluid and a firm pedal. Bed pads with ten 40 km/h stops, cooling a minute between.
Seasonal maintenance routine
Rinse after salt, change fluid and grease bearings each six months, swap pads at 3 mm.
Troubleshooting common issues
- Soft pedal: bleed or fix leak
- Side pull: greasy pad
- Hot hub: dragging caliper
15. Frequently Asked Hydraulic Brake Questions
Still scratching your head about the finer points? The quick-fire answers below clear up the issues we hear most on the shop floor.
Are hydraulic trailer brakes better than electric for boat trailers?
Yes—sealed hydraulics keep magnets and wiring out of the water, purge salt faster, and bite sooner once you leave the ramp.
Do I need a brake controller in the tow vehicle?
Not for surge-coupled systems under 2 000 kg ATM. Electric-hydraulic or IQ7 style units do require a 12 V feed and in-car controller.
Can I retrofit hydraulic brakes on my existing electric-braked axle?
Often, if the axle has a standard four-bolt flange. Swap the actuator, run new lines, and get a cert plate if ATM exceeds 3 500 kg.
How long does a DIY installation take?
Expect three to four hours for a single axle and six to eight for a tandem, including bleeding and bedding-in.
What brake fluid should I use?
Stick with DOT 3 or DOT 4 glycol-based fluid; avoid DOT 5 silicone—it aerates easily and traps moisture.
16. Final Brake Check
From the compact Trojan combo drum to Titan’s 9-tonne giant, the 12 kits above prove there’s a hydraulic trailer brake solution for every load, budget and coastline run in Aotearoa. Match the kit’s axle rating to your ATM, pick materials that survive your launch ramp or dust track, and choose an actuator style that keeps you on the right side of the NZTA rule book. Nail those three decisions and your trailer will stop straight, quiet and legal for years. Need a second opinion or same-day parts? Pop into the Auckland store or jump online at ActionOutdoors.kiwi for personalised advice and bundle savings.
