Over-Ride Hydraulic Disc Brakes

Hydraulic ‘over-ride’ brakes are a totally (trailer) self-contained braking system, requiring no electrical, external hydraulic or other connection of brake sensing components to the tow vehicle for automatic operation of the trailer brakes. In a hydraulic ‘over-ride’ brake system, the inertial differential pressure developed between the tow vehicle and the trailer, during the braking process, creates a mechanical pressure which is applied to the push rod of the master cylinder in the hydraulic ‘over-ride’ brake coupler. This mechanical pressure is proportional to the difference in pressure between the two vehicles and therefore, the hydraulic output & resulting brake operation, is automatic, regulated, and proportional to the amount of braking being applied to the tow vehicle.

Simple, effective and a proven performer on thousands of trailers, this brake system has been the braking package of choice for most trailer owners for decades. The vast majority of trailer hydraulic ‘over-ride’ brake systems are package with drum brakes; however at Kimberley Kampers we use disc brakes.

Because brakes work by friction there is wear of shoes and drums. Most wear is directed at the shoes. These are lined with a high friction material to reduce their size. The drums and shoes must be heat resistant and dissipate the heat generated effectively. Generally brake effectiveness deteriorates as the brake mechanism heats up. Disk Brakes use pads which clamp on either side of a ventilated disk (rotor). Disk brakes are usually better at dissipating heat, are self cleaning and lighter. Disk brakes are much lower in maintenance in dusty conditions and when traversing water crossings.

Electric Brakes

Electric brakes require a brake controller to apply power to the brake system. With electric brakes, as power is applied to the electromagnets in the brake cluster, the magnets are pulled to the interior flat surface of the hub drum. As the wheel and drum turn during highway travel, this attraction of the magnet to the flat drum face pulls the lever arm of the brake actuating cam, rotating the cam and forcing the brake shoes out to contact the drum braking surface. The more power applied to the magnets the greater the leverage on the came resulting in greater braking response.

Most electric brake controllers are dash mounted allowing the driver access to the manual override button. The manual override button allows the driver to activate the trailer brakes without operating the tow vehicle braking system. One positive of Electric brake controllers is that they can be activated downhill and when reversing uphill.

One negative feature of electric brakes is that if you use a dash mounted brake controller, you must have a controller on every vehicle that you tow the electric brake equipped trailer with.

Electric brakes are commonly used in caravans. In on-road applications, their internal brake pads and magnetic actuator provide excellent service if properly installed, wired and maintained. In off-road applications, the drum brakes and magnetic actuator require regular maintenance.

Electronic Disc Brakes

(Notice we don’t be calling them “electric brakes” as they do NOT use an electric magnet for activation – we call them “electronic” because of the controller)

This is the best of both worlds with the convenience of Electronic brake control but with the high durability, high performance and low maintenance of hydraulic Disc brakes.

 A HydraStar™ actuator is fitted into the trailer drawbar. It is complete with hydraulic actuator but instead of a mechanical ‘over-ride’ coupling, it is connected to the vehicles electric brake actuator. Combined with the Disc brakes, it has faster response for reduced stopping distance.

For the parking brake, an auxiliary switch is fitted wired to the trailers on-board battery system. This activates the disc brakes which are held ‘on’ by a locking valve located beside the auxiliary switch. There is no need to exert force or take the strain compared to traditional mechanical parking brakes.

The unit is a sealed unit - weather tight. This system eliminates the feel of being pushed by the trailer when traveling downhill, and eliminates the problems with backing a trailer uphill and brake drag.

Comparative Pricing

Electric brakes are the least expensive. There is a premium of approx $990 to go to Hydraulic over-ride Disc brakes and upgraded shock absorbers.

The Electronic Disc Brakes unit is an option available to any model with Over-ride Disc Brakes with a retail price of $1590.

Electric Brakes

Brake Systems and Models	Electric Brakes (10 inch)	Over-ride Disc Brakes	Electronic Disc Brakes
Max ATM for braking	1500kgs dry much less in wet Not suitable for units with Boat Loaders and outboards	2000kgs dry less in wet All round workhorse	2500kgs dry less in wet Suitable for high country Treks with severe downhill conditions.
SportsRV	Standard	option	option
Kimberley Kamper (With Delta Gullwing)	Standard	Option	Option
Limited Edition	_	Standard	Option
Platinum	_	Standard	Option