How To Determine If Boat Trailer has 10 Inch or 12 Inch Brake Assemblies

Question

Question:

I have a boat trailer and need to replace the brakes. I know I have a #84 spindle, 15 inch rims 5 lug at 4.5 inch spacing...Is there a way to tell if I need 10 inch or 12 inch brakes? Thanks.

asked by: Paul

0

Expert Reply:

When determining if you need 10 inch or 12 inch brake assemblies there are a couple of easy things to check to confirm the fit for your trailer. The first thing is you can measure the diameter of your hub. The second thing is you can look at the brake flange, if it has 4 bolts then it is 10 inch if it has 5 then it is 12 inch.

Because you know you have a #84 spindle we can be confident that you have a 3,500 lb axle and you will need the 10 inch assemblies. I recommend the Hydraulic Brake Kit - Uni-Servo - Free Backing # AKFBBRK-35-D which will fit your current hubs. If you also want to upgrade your hubs while you are at it, I recommend the Galvanized Hub/Drum # AKHD-545-35-G-K for your boat trailer. If you have EZ Lube Spindles then # AKHD-545-35-G-EZ-K will come with the grease cap that allows for that zerk access.

If you have electric brakes on your boat trailer then you can use # AKEBRK-7-SA for 12 inch or # AKEBRK-35-SA for 10 inch assemblies.

expert reply by: Jason S

0

Randell

12/1/2024

I have a two axle trailer custom built for a cobalt 226 with disc brakes on the front axle only. In 2018 I had a shop replace the brakes. We used the boat very little and only made short moves from storage to the ramp. We made a trip to San Antonio from San Francisco when we moved in May 2022. Upon arrival the pads were almost completely worn away. We replaced the pads and have put less than 500 miles on the trailer. While doing maintenance repacking the bearings we found that the right side pads were already heavily worn unevenly. We decided the mounting brackets may have bent so we replaced the mounts. Calipers and pads with new. They are tie down G5 9.6 disc brakes. After a short trip to the storage yard of less than 10 miles the brakes are locking up. Question Should this trailer have larger brakes? Brakes on both axles? Or have we done something drastically wrong? Thanks

Robin H.

12/1/2024

@Randell assuming you have 3,500 lb axles it is probably safe to assume your brakes match the capacity of the axle so you're putting a lot on a single set of brakes. I would definitely add brakes to that other axle. As an example, say you do have two 3,500 lb axles and your Cobalt 226 is 5,000-6,000 lbs loaded on the trailer. Your single set of brakes designed for 3,500 lbs is going to wear down significantly faster because it has to stop all of that extra weight beyond its capacity. If you share that weight between two sets of brakes, just like you do with the axles, the wear on the brake pads will be normal since the combined rating is 7,000 lbs which is in line with your boat and trailer.

Randell

12/1/2024

@RobinH Thanks for your quick reply. Sort of disappointed with cobalt’s choice af brakes on the trailer.

Robin H.

12/1/2024

@Randell if you can identify the axles I can help you find replacement brakes and an extra set of brakes for the axle without them. Tie-down engineering is no longer around so we wouldn't be able to match the other set but we have good replacement options. While you're at, it you will also need to make sure that other axle has a brake flange. If it doesn't, you'll have to add one or replace the axle with one that has a brake flange to install another set of brakes. I'm sure wherever/whenever that trailer was built it only needed brakes on a single axle by law so that is what they did to save money. Just like a lot of utility trailers for heavier loads can come without brakes because the state they're manufactured in doesn't require them by law, even though they really should come with them.

Answer 1

Hey Tom, thanks for reaching out. Wheel compatibility actually comes from the hub since the surface area on the hub is what determines the wheel size. So, if your trailer already uses 10" drums and 13" wheels, there will be no problem using…

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Answer 2

Hello Connie, thanks for reaching out. Yes, a modern ST205/75R14 is the current metric equivalent to the older F78-14ST size. The overall diameter and width are very close, so it is considered a direct replacement. With a GVW of 1,480 lbs and two…

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Answer 3

Hi John! Though you want the tires to match for consistent wear and stuff like that, the load rating being slightly higher on a spare will be perfectly fine. If it was a completely different size or a lower load range, I would be saying something…

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Answer 4

In order to determine if hub assembly 8-258-50UC1-EZ will work for you, first know that this assembly is for EZ Lube spindles that require a grease seal with a 1-1/2" inner diameter such as #RG06-020. You are also going to want to remove the hub…

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Answer 5

Hello Myles. The Trailer Hub and Drum Assembly - 5 on 5-1/2 inch bolt pattern #AKHD-555-35-EZ-K is my recommendation over the Dexter #84557UC3. They are basically the same assembly made by different manufacturers and the Dexter assembly simply has…

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Answer 6

Hey Steven, thanks for reaching out. It may be possible to add brakes to your trailer. The first thing you will want to verify is that your axle has a brake flange. It should look something like part #4-35. If no brake flange is present, they can be…

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Answer 7

Hey Brian, yes the grease seal of the Easy Grease Trailer Hub and Drum Assembly for 3.5K Axles #AKHD-545-35-EZ-K is designed to prevent grease from getting on the brake components. But what I would guess happened to you is that you overfilled the hub…

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Answer 8

Surge brakes use a hydraulic actuator to push fluid to the cylinder piston to activate the brake shoes on drum brakes or brake pads on disc brakes. This pressure should only be applied when weight is pushing against the hitch ball, so no pressure…

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Answer 9

Hey Roger, thanks for getting in touch. I can certainly point you in the right direction here, but there is no way to know exactly what hub you need based on the trailer model or VIN. Trailer manufacturers just do not make this kind of information…

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Answer 10

Hello Casey, thanks for reaching out. It sounds like the 2,200 lb Timbren Axle-Less Trailer Suspension #ASR1THDS03 will be sufficient for your build. Even if the GVWR is 1,500 lbs and your water tank is full, you would still be safely under 2,200…

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Answer 11

For your application you need the Easy Grease Trailer Hub and Drum Assembly for 3.5K Axles #AKHD-545-35-EZ-K to replace the Tru-Ryde RVD-H-545 trailer hub/drum assembly. This is designed for the industry standard #84 spindle so it uses inner bearing…

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Answer 12

The Trailer Hub and Drum Assembly part #AKHD-545-35-EZ-K would be an excellent replacement for a Tru-Ryde Hub/Drum RVD-H-545. Then for new brakes, I recommend the Hydraulic Trailer Brake Kit part #AKFBBRK-35.

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How To Determine If Boat Trailer has 10 Inch or 12 Inch Brake Assemblies

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