Give Me a Brake!

Surge BrakeOne would think that there was a weekend push, pull or drag sale on trailers. I once checked three of them on a Friday evening and found one that was too heavy for a surge brake, one that had no brakes functioning and a third that needed brakes but was not equipped with them. The one with no functional brakes was being towed by a class one driver, and the other two by drivers who likely didn't know any better.

A hydraulic surge brake cannot be used where the trailer and it's load weigh more than 2,800 kg. When it is this heavy, the driver must have a means of applying the trailer brakes separately from the tow vehicle brakes from where the driver is seated in the cab. A combination electric and hydraulic brake is most commonly used on boat trailers for this purpose.

The class one driver was clearly negligent. The breakaway brake activation lever and cable was missing entirely from his trailer. A quick look inside the master cylinder on the surge brake revealed that there was no fluid inside it. This trailer should never have left the yard.

The third trailer weighed just under 1,400 kg and the driver towing it said that he had been told by the business that sold it to him that it was not heavy enough to require brakes. The net weight (shown on his vehicle registration document) of the vehicle he had chosen to tow the trailer with was just over 1,800 kg. This means that the trailer and load cannot weigh more than half of that figure or 900 kg. if it is to operate without brakes.

All three drivers had no clear idea how much their trailer weighed. The only sure way to know this is to go to a scale and have it weighed. Once that is accomplished, it is time to consider brake requirements.

For the simplest cases, if the total weight of the trailer and load is under 1,400 kg but more than 50% of the net weight of the towing vehicle, brakes are required. If it weighs 1,400 kg or more, brakes are required. If it weighs more than 2,800 kg a surge brake cannot be used and a different braking system is required.

Lastly, a word about breakaway brakes. These are required on trailers that weigh 1,400 kg or more when loaded. They are designed to stop the trailer and hold it stopped for a minimum of 15 minutes should it accidentally disconnect from the tow vehicle. Don't attach the lanyard for activating the brake to the hitch assembly or safety chains! Attach it somewhere else on the tow vehicle so that if the hitch fails the brake will still activate.

References:

Brakes - Division 5 MVAR

Commercial Trailer Brakes - Division 6 MVAR

Towing a Recreational Trailer - Chapter 2, Page 14

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