How To Determine Axle Weight Capacity To Replace Brake System On Custom Boat Trailer
Question:
I recently purchased a single axle boat trailer carrying a Catalina 22 sailboat ~2600# that might be a custom trailer, and I want to upgrade the surge brakes from drum to disc. I am looking at Titan Disc Brake Kit and Aero 7500 Actuator w/ Manual Lockout - Single, 3,500-lb Axle #T4843500. How do I go about identifying my axle/spindle to know if the kit Im considering will fit? Id like to be sure I have spindles with the correct load rating. From what I can see, its a 4 bolt, 5 lug integrate drum brake/hub assembly. The current brakes, to my knowledge, are nonfunctional with a possible dry hydraulic lines. The trailer is pointing down a very slight sloping driveway. One wheel has 2 broken lugs, leaving 3 intact. The other wheel has 5 intact lugs. Can I safely put the trailer with boat on jack stands without the tow vehicle attached to do the spindle/brake work? Thank you for any help and recommendations. PS- I have a bunch of pics for you, too. How do I send them?
asked by: John M
Expert Reply:
You will want to move the trailer to a level area where you can place it on stands so that you can remove the wheels and any other components in a safe manner. I recommend removing the boat from the trailer so that you have ample room to check all of the trailer components and also enough room to install anything needed to get the trailer in good working order.
Before you order the brake kit you will want to make sure you know what the axle capacity and trailer capacity is. Normally there is a plate or sticker on the axle and or trailer that will list the towing weight capacity. I have attached a helpful article you can check out that explains what is needed to add hydraulic disc brakes to a trailer.
If you cannot find a plate or sticker, you can pull the bearings and see what the numbers are on them to help determine what size axle you have on the trailer. I have attached a drawing that shows where you can normally find the numbers on the bearings, races, and seals. As a last resort, you can use a precision instrument like a dial caliper and take the measurements of the spindle in the noted places per the drawing and also the diameter of the axle and we can hopefully find the items you need.
You will need to know the bolt pattern on the hub for your tire/wheels. I have attached a helpful article that explains how you measure to determine the bolt pattern of your wheel. The Titan Disc Brake Kit, part # T4843300, you referenced is for 14, 14-1/2, or 15 inch wheels with a bolt pattern of 5 on 4-1/2 inch, and an axle capacity of 3,500 lbs.
While you have the trailer raised you will want to check out all of the suspension components and replace any that show signs of wear or corrosion. If you replace any parts of the suspension it is recommended to replace both sides of the trailer at the same time so that you maintain equal support for the trailer.
