How to Measure to Determine the Size Trailer Brakes Needed For Hydraulic Drum Replacement

Question

Question:

Where does the measurement come from to determine if I have 2-1/4 or 2-1/2inch brakes? I need to replace the brakes on a Road King boat trailer with 3700# axles. It seems the wheel cylinder is blown out and rather than buying piece parts you kits seem to be the best option.

asked by: Chris

1

Helpful Expert Reply:

To determine the size of the brake assemblies you need you have to measure the depth and width of the hub drum on the axle like what you see in the picture I attached. The most common size is 2-1/4 inch wide like the # T4071600-500 that you referenced.

expert reply by: Jameson C

1

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Matt O.

8/7/2020

12 x 2.5 drum trisaler brakes i just want the whole brake whitout botor i need probably 5

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Jon G.

8/18/2020

Sounds like you're looking for the Brake Kit # 23-428-429 which is rated for a 7,200 lb axle. This kit comes with both the right and left brake assemblies and it doesn't come with the hub and drum - just the brakes.

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Joe C.

9/4/2025

10" x 2.5" - double axle can you give me a part number

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Jameson C.

9/4/2025

@JoeC Are you sure the width is 2.5 inch and not 2.25 inch?

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Joe

9/4/2025

2.25 sorry

Reply

Jameson C.

9/4/2025

@Joe Gotcha, you'd just need the # AKEBRK-35-SA.

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See All (7) Replies to Joe C. ∨

Answer 1

Hey Tom. The highest capacity drum brake assemblies we have for a 4 bolt brake flange are the Dexter Electric Trailer Brakes item #23-105-106-09. These are a 6,000 lbs set that are mainly used with AL-KO/Hayes axles. Do you have any part numbers or…

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Answer 2

The inside diameter and the depth of the brake drum is what determines the necessary width of the brake pads. For example, the 10 inch x 2-1/4 inch Electric Brake Shoe, part number BP04-090 that you refer to would fit a brake drum with a 10 inch…

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Answer 3

We don't have any way of knowing the brakes you need for your Shorelander boat trailer but can tell you how to determine the right ones. To determine the brake assemblies that will fit your trailer, you need to know your axle's weight…

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Answer 4

It sounds like you are speaking of the wires for the brake magnets. If this is correct, you will need to connect one of the wires to the brake controller output wire on your trailer connector and the other wire will need to be grounded to a clean…

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Answer 5

Even though I cannot comment specifically on the grease you used because I am not familiar with it, I can tell you the best grease for trailer bearings is a a grease with a rating of GC-LB, which just means it is made to withstand very high…

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Answer 6

You would know to replace brake shoes the same way you would know with a vehicle. If performance is suffering and adjusting the brakes does not help and there are no other issues causing the poor performance it is probably time to change the brake…

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Answer 7

On Dexter 12" Nev-R-Adjust Electric Brake Assembly #23-458 the shoe pad thickness is 3/16 of an inch. Dexter says that you should replace the shoes if the material gets down to 1/16 of an inch thick or less.

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Answer 8

I do have a couple possible solutions for raising your pontoon trailer, however increasing the shackle strap size will not be your best option. A more efficient way for raising the suspension on the trailer will be to use longer hangers. Unlike…

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Answer 9

The Dexter hub you referenced, 8-201, is a 5,200 lb hub, though a 5 on 4-1/2 bolt pattern does not come on 5,200 lb hubs. The correct bearings for the 5,200 lb hub are #25580 and #LM67048, while the proper races are #25520 and #LM67010. I have…

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Answer 10

In order to determine the torque rating for the lug nuts on your trailer you will need to know check out the chart I attached that shows all of the torque specs for all the trailer lugs available based on stud size, wheel material and wheel size.

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Answer 11

You will need to do some measuring to determine if the 10 Inch Electric Brake Assembly LH, item #AKEBRK-35L, is the correct assembly for your trailer. Measure the diameter of the mounted brake shoe, the width of the lining and the distance between…

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Answer 12

Hey Deb! That 6" maximum trailer frame height is pretty important because of the brackets and how they attach to your trailer. What that measurement is referring to is how tall your trailer's tongue is. I have attached a diagram below to…

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How to Measure to Determine the Size Trailer Brakes Needed For Hydraulic Drum Replacement

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