Buying overrun brakes on trailers
When you replace an overrun brake on your trailer, we recommend always buying an overrun brake of the same brand as the one currently fitted on the trailer. This is part of the braking scheme that determines the braking force on the drum. You also know immediately that it fits. You can notice this because the Trailer pushes on the car without braking itself. This can happen with a bang because the damper of the overrun brake, for example, is broken. This is relatively easy to check. Can you press the coupling with your hands and it does not spring back? Then most likely your overrun brake trailer damper is faulty. It could also be that the Draw tube is warped so that it can no longer slide in and out of the overrun brake housing properly.
Want an expert to assess it? Then drop by our branch and our BOVAGmechanic will check it right away.
What is an overrun brake anyway?
Trailers heavier than 750 kg have overrun brakes. An overrun brake ensures that the brake function of the trailer is activated when the towing vehicle slows down, so that the trailer 'runs up/down' on the towing vehicle. There are also trailers with a gross payload of 750 kg or less that have an overrun brake, this is done to improve the handling and roadholding of the trailer or caravan. If a trailer is heavily loaded and does not brake with the towing vehicle, it is not safe. An overrun brake ensures that you are safe on the road with a heavily loaded trailer.
An overrun brake ensures that the Trailer brakes with you.
An overrun brake is designed to ensure that the Trailer behind the towing vehicle brakes with it. The overrun brake operates when a negative tractive force is created on the drawbar. This happens when the towing vehicle brakes or descends. This attracts the brake rod, which presses the brake shoes against the drum. So it is a drum brake that many cars used to be equipped with. So it is completely mechanical and has no electronic couplings. Trailer brakes because the overrun brake damper slides in and pulls the brake cables. Check the brake assembly regularly and maintain it where necessary so that you can always stay safe on the road.
Which overrun brake do I need for my Trailer?
We offer four different brands of trailer and caravan overrun brakes. Knott, AL-KO, BPW and Peitz. So how do you decide which brand you need? Our advice is always to take the same brand as what is currently on the Trailer or caravan. This is what the braking diagram is based on which has given the Trailer European approval. After that, the type is also important. The dimensions are different and the brake parts may be connected differently or have a different function. Due to our large purchasing volumes, we can offer overrun brakes at competitive prices. This applies to all brands such as AL-KO, Knott, BPW and Peitz. This also makes it cheaper to replace the entire Delta coupling of the trailer instead of all the individual parts. This also saves a lot of assembly time and gets you back on the road quickly. Need advice on the right overrun brake? Then do not hesitate to contact us.
Replacing the overrun brake on a caravan
In Europe, almost all caravans are equipped with an overrun brake. Most caravans have an AL-KO undercarriage and therefore also an AL-KO overrun brake. The correct type is always indicated on the overrun brake itself with a type plate. So you always know which type of overrun device the caravan has and which parts you therefore need to repair it. Are you planning to visit a mountainous country with your caravan? In the mountains, an overrun brake sometimes has its limitations. For example, are you driving down a steep slope at a constant speed (when braking on the engine)? Then the caravan will press against your car. This causes the caravan to brake constantly. As a result, the caravan's brakes may overheat. The best thing to do then is to stop occasionally and let the brakes cool down. The same applies to caravans as to trailers; always replace the trailer or caravan overrun brake with an identical type or successor of the original overrun brake. That way you will always be safe on the road!
Reversing the caravan overrun brake
Even when reversing, the car presses against the caravan, causing the caravan's brake to kick in. To prevent this, most brake drums are fitted with a reverse automatic. A return actuator ensures that, via a circuit (mechanical), the brake shoes press less violently against the brake drums at the moment the brake drums reverse. You can then still drive backwards with a depressed sliding piece, with some resistance. A reverse automatic also ensures that if you put your caravan on the handbrake, it can still drive backwards by half a metre. This is why you should never actually unhitch caravan or trailer on a slope backwards just like that. In all modern overrun brakes that we sell as standard, the system is set up so that the overrun brake does not lock when reversing. If you have an older type of overrun brake without a reverse drive system, you will have to move a lever manually. When reversing a trailer or caravan, force is applied to the overrun brake in the same direction as when you brake. Without a reverse gear, the overrun brake slams into the brake. For this, there is a built-in mechanism (lever) that can temporarily disengage the overrun brake. Afterwards, remember to put the lever back on to prevent damage.
Overrun brake damper of the overrun brake
An overrun brake damper is a wear-sensitive part of the overrun brake. The Overrun brake damper is located in the sliding part of the overrun brake. The overrun brake damper ensures that your trailer or caravan brakes in a dosed manner. So if you brake gently, the Trailer should also brake gently. But even if you make an emergency stop, for example, the trailer should brake hard right away. You can often identify a worn overrun brake damper by a thumping noise while driving the trailer or caravan. An appropriate Overrun brake damper depends on the mass of the trailer or caravan. The greater the mass of the trailer, the greater the damping factor should be. See also our Overrun brake damper range here.
Lubricating overrun brakes
Every overrun brake has a grease nipple (grease nipple). This is often a Metal part, e.g. made of stainless steel or brass, which is fixed in a drilled hole in machine parts and through which a grease nipple is pressed under pressure into the housing of a bearing. A grease nipple often protrudes from the side of the housing. You can attach a grease gun to this. Grease nipples should be greased regularly to prevent wear. Doing this early ensures that your overrun brake functions safely and properly. In addition, you also prevent the overrun brake from suffering from rapid wear. It is often a simple job, yet this overrun brake maintenance is often forgotten. Greasing the grease nipples of the overrun brake almost always guarantees optimum long-term operation.
Need further advice? Do not hesitate to contact us.