Recommended Replacement Hydraulic Brakes with 10-Inch Diameter for a Boat Trailer?

Question:

I want to replace hydraulic surge brakes on my boat trailer. I have removed the brake drum and measured the inside diameter of the drum, which is 10 inches. I did not check to see what brand of hydraulic assembly i have, do I need that to find the correct size of hydraulic replacement assembly? I need both the right and left wheel assembly. I have checked my trailer's GVW and it is 6000 lbs. What weight of brake assembly will I need? Will 3500 on each wheel satisfy the weight requirement?

asked by: Kent R

Expert Reply:

Knowing the inside diameter of the drum is the key piece of information we need; the brand of the assembly will not be a factor in determining what you will need to replace your hydraulic brakes. You mentioned your trailer's GVW, but it is the trailer's axle weight capacity which determines the size of the brake assembly you are going to need. For example, a drum with a 10-inch diameter like yours fits brake assemblies for a 3,500 lbs axle.

For your boat trailer, I recommend the Demco Hydraulic Brake Kit, # 40716-15. It has dimensions of 10 inches by 2-1/4 inches, is made of galvanized steel to resist the corrosion that can occur on boat trailers, and has a free-backing design that will allow you to back up without the trailer brakes activating.

As for weight requirement, that depends on if you have a dual or single axle. Boat trailers commonly use brakes on only one of the dual axles, and even though it does not meet the weight capacity of the trailer, it is better than not having brakes at all. For optimum stopping power, you will ideally want to put brakes on both axles.

I have attached a link to a help article which goes into detail about each of the necessary parts you will need in order to replace your hydraulic drum brakes.

expert reply by: Kyle S