Trailer Brake Maintenance

Those who own larger, heavier, fiberglass bass boats need assistance in slowing down or stopping their pride and joy. Most boat manufacturers now offer trailer brakes on any boat package, and highly recommended on larger boats. Trailer brake failure is very dangerous. Drivers are accustomed to having the assistance when stopping, when it’s not there the driver’s judgement is off and stopping distance is severely increased. Trailer brake maintenance is a must to ensure when needed, the brakes work properly.

Back in the day, surge brakes with drums were the only style of brakes available for a boat trailer. This type of surge brakes did a very good job of stopping a boat trailer. However, they need to be set up properly, adjusted regularly and maintained correctly. For these reasons trailer brake maintenance was very important. When something does fail in the brake system the driver knows immediately.

Older surge brake systems utilized brake shoes inside a brake drum activated by a brake master cylinder in the trailer tongue. The master cylinder is activated by the trailer weight pushing forward against the tow hitch. This pushes brake fluid through the lines to move the brake shoes out against the brake drum.

I have had a couple of tandem axle trailers with drum surge brakes installed on the rear axle. They worked well in keeping stopping distances shorter. The only down side to surge brakes, of all kinds, is backing the trailer on an incline. Surge brakes will activate and make it almost impossible to back up hill. Many designs have a pin to insert, and others have a connection to the back-up lights circuit to disable the surge brakes when in reverse.

Trailer brake maintenance on these older systems is relatively straight forward:

  • Check all metal and flexible brake lines periodically. Those who fish tidal or salt water should do this more often since the metal lines will eventually rust.
  • Check the flexible lines for cracks. I recommend replacing the brake lines with the
    new alloy line when replacement is necessary.
  • Check the master cylinder fluid level. Refill as necessary with the manufacturer’s suggested brake fluid. The type brake fluid is normally shown on the master cylinder cap. If the master cylinder is low on brake fluid make sure to find out why.
  • Check the brake shoes, hardware kit and wheel cylinders when repacking bearings or when brake fluid is noticed leaking behind the brake backing plate.
  • The addition of a fresh water rinse system helps these last a bit longer before failure inside the brake drums.

Quite a few years ago some trailer manufacturers opted to go to surge brakes utilizing disc brakes. Most of today’s trailers now have disc surge brakes. These use high carbon content rotors and other parts to limit the damage caused by tidal and salt water. Because disc brakes have brake calipers and rotors, trailer brake maintenance should be stepped up a little. Rust or corrosion can lock up a caliper causing rapid brake pad wear and make a brake rotor wear below the safe thickness specification. This of course will cost a lot more in the long run.

Disc surge brakes operate on the same principles as drum surge brakes, so the maintenance is basically the same:

  • Check all metal and flexible brake lines periodically. Those who fish tidal or salt water should do this more often since the metal lines will eventually rust.
  • Check the flexible lines for cracks.
  • Check the master cylinder fluid level and keep full of the manufacturers recommended fluid. One major change is the master cylinder level will drop because more brake fluid will be stored in the caliper as the brake pads wear. If the master cylinder level is low, refill it. If master cylinder is very low or empty, check for leaks in the system somewhere.
  • Keep an eye on the brake caliper, brake pads and hardware periodically. Clean the caliper slides and lube when servicing the hub bearings or a problem is noticed.
  • Flush with fresh water after every trip in brackish or salt water. Don’t forget between the brake disk and backing plate.

Some trailer manufacturers are using, or have an option for electric brakes on their trailers. These brakes are very good at slowing or stopping a heavier trailer. This is the same style brake system used on RV and small commercial trailers. The backing plate looks a lot like the surge brakes shoes but does not have the wheel cylinder and other hydraulic parts. Instead of brake fluid forced through the brake lines to expand the wheel cylinder it has a magnet which pushes the brake shoes out against the brake drum. Hydraulic parts like the master cylinder, brake lines/hoses and wheel cylinders are replaced by electronic/electrical parts.

The electronic parts include a brake controller to apply electricity to the magnets on the backing plate to assist in slowing or stopping the forward motion of the vehicle. If not familiar with wiring one of these systems, find a professional to install it. After installation, there are adjustments which must be made to set the parameters for braking. Some newer trucks and SUVs have the controller installed in the dash which is very convenient. Maintenance on these systems is very easy. Most brake controllers tell the driver when there is a fault and basic information to help correct any issues.

These systems usually use the seven pin, round plug for connection to the trailer. The braking wires are usually a little heavier gauge because of current flow. Behind this connector on the vehicle is where I often find corrosion from road salt. Normally, if I have problems with lights or brakes it is the first place I check. Local wildlife is another cause of faults in these systems. Squirrels, ground hogs and others critters chew on the wiring. I have seen this many times when I was a service manager at dealerships.

I suggest once a year while checking/repacking the wheel bearings be sure to check the brake shoes for adjustment and wear inside the drum.

No matter what system is on the trailer, periodic trailer brake maintenance is key to limiting the possibility of a failure while on the road. Keeping the systems working at their best will keep the trailer from pushing the vehicle when trying to stop.

Happy trailering and keep on smiling.

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