Brake Kit and Actuator Needed for a Tandem Axle Boat Trailer

Question:

Tandem boat trailer, 3inch beam at tongue, 5 bolt pattern wheels 4.5inch lug circumference. Need all items, surge brake/tonge and 4 disc or drum brakes. What do you recommend? The trailer is twenty years old, no name brand.

asked by: Matt P

Expert Reply:

There are a few things we will need to know before selecting the correct brake kit and actuator for your tandem axle boat trailer. We will first need to know what type of brakes you are choosing and the gross trailer weight of your trailer before selecting an actuator.

The first item to check when choosing brakes is to make sure there is a brake mounting flange attached to the axle. If it does not have a brake mounting flange, you would first need to have one welded to the axles by a qualified professional. The positioning of the flange needs to be precise, so someone with experience with trailer repair should perform the installation.

The next part is to check your axle capacities and either the spindle or bearing and seal dimensions. The easiest way to verify the bearing and seal dimensions is to find the part numbers located on the bearings and seals. If you are unable to get the part numbers then you can take some measurements of the spindle or bearings and seals using a precise measuring tool like a digital caliper. I have attached a photo showing where to measure on the spindle for the correct bearing size.

After that, you will want to decide if you want to use disc or drum brakes. Disc brakes typically work better with heavier applications and have less moving parts, but drum brakes are typically more inexpensive. If you currently have disc brakes, then we will need to know the rotor diameter and wheel bolt pattern. For drum brakes we will need to know the brake assembly diameter and width and the hub diameter and bolt pattern.

If you currently do not have brakes, then the correct brake assembly will be dependent upon the brake mounting flange bolt hole measurements and your wheel size and bolt pattern.

I have attached an two articles and a photo explaining the various parts needed to add brakes to a trailer.

expert reply by: John H