1. Trailer Brakes
  2. Demco
  3. Hydraulic Drum Brakes
  4. 3500 lbs Axle
  5. 10 x 2-1/4 Inch Drum
  6. 13 Inch Wheel
  7. 14 Inch Wheel
  8. 14-1/2 Inch Wheel
  9. 15 Inch Wheel
Demco Hydraulic Brake Kit - Free Backing - Galvanized - 10" - Left/Right Hand Assemblies - 3.5K

Demco Hydraulic Brake Kit - Free Backing - Galvanized - 10" - Left/Right Hand Assemblies - 3.5K

Item # 40716-15
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Demco Hydraulic Brake Kit - Free Backing - Galvanized - 10" - Left/Right Hand Assemblies - 3.5K Free Backing 40716-15
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Free-backing, driver's-side and passenger's-side brakes won't engage when you reverse, even if your actuator is activated. Galvanized steel resists rust, making the assemblies great for boat trailers. Fit 13" to 15" wheels. Lowest Prices for the best trailer brakes from Demco. Demco Hydraulic Brake Kit - Free Backing - Galvanized - 10" - Left/Right Hand Assemblies - 3.5K part number 40716-15 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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  • Reviews (40)
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Demco Trailer Brakes - 40716-15

  • Hydraulic Drum Brakes
  • 3500 lbs Axle
  • 10 x 2-1/4 Inch Drum
  • 13 Inch Wheel
  • 14 Inch Wheel
  • 14-1/2 Inch Wheel
  • 15 Inch Wheel
  • Demco
  • Free Backing
  • Brake Set

Free-backing, driver's-side and passenger's-side brakes won't engage when you reverse, even if your actuator is activated. Galvanized steel resists rust, making the assemblies great for boat trailers. Fit 13" to 15" wheels.


  • Marine-grade hydraulic drum brake assemblies are great for boat trailers
    • Designed for use with surge-type trailer brake actuators
  • Sturdy, corrosion-resistant steel construction
    • Galvanized backing plates
    • Stainless steel spring hardware
    • Zinc-plated wheel cylinders
  • Free-backing design lets you back up without engaging the trailer brakes, even if the actuator is activated
    • Riveted, fall-away brake shoes only anchor on drums when brakes are engaged as trailer is moving forward
  • Periodic manual adjustment required
  • Adjuster plugs (included) cover access holes to keep dirt and grime out of the assemblies and off of the shoes
  • Left-hand (driver's-side) brake assembly and right-hand (passenger's-side) brake assembly included
    • Mounting bolts and hardware sold separately


  • Dimensions: 10" diameter x 2-1/4" wide
  • Mounting flange bolt pattern: 4 bolt
    • Measurement between center of mounting hole to center of mounting hole: 2-3/4"
    • Diagonal measurement between mounting holes: 4"
  • Wheel size: 13", 14" or 15"
  • Axle rating: up to 3,500 lbs
  • 1-Year warranty

Note: Because free-backing brakes are designed to eliminate nearly all friction between the brake shoes and the drum when you are driving in reverse, a trailer breakaway kit will not be effective should your trailer disconnect from your tow vehicle while you are backing up.

Free-backing brakes let your trailer move in reverse without the brakes being activated by your surge actuator. These brakes are needed if your actuator does not have a reverse lockout, which is a mechanism that ensures that the actuator does not activate when your rig moves in reverse.

Demco Free-Backing Brakes with Fall-Away Shoes

Each of these Demco free-backing brake assemblies has a fall-away shoe that is designed to provide full braking action when your trailer is moving forward and to supply only limited friction when the trailer is moving in reverse. This is largely due to the incorporated dual springs at the shoe's pivot point. (One spring sits on either side of the shoe lever, so only a single spring is visible when looking at the brake assembly.)

Demco Free Backing Brake Labeled Diagram - Right Hand Assembly

When your rig is moving forward and you engage the trailer brakes, each fall-away shoe expands normally, with the leading edge of the shoe catching the drum. This occurs because the plunger on the hydraulic cylinder pushes on the shoe lever, forcing the leading edge of the brake shoe into the drum. Once that edge catches, the dual springs at the shoe's pivot point facilitate braking by forcing the rest of the shoe to pivot into the drum. The action of the shoe against the drum provides the friction required for braking.

When you are driving in reverse, however, the hydraulic cylinder and the springs work against one another. Even though the plunger pushes on the shoe lever, the dual springs of the fall-away shoe overcome the pressure from the brake cylinder, keeping the leading edge from catching on the drum and ensuring that the shoe does not fully pivot into the drum. Because the shoe makes only slight contact with the drum, just enough friction is generated so that only a minimal amount of braking occurs when you are in reverse.

SB40716M Demco Galvanized 10" Marine Trailer Brake Assembly - Freebacking - Left Hand

SB40715M Demco Galvanized 10" Marine Trailer Brake Assembly - Freebacking - Right Hand

Video of Demco Hydraulic Brake Kit - Free Backing - Galvanized - 10" - Left/Right Hand Assemblies - 3.5K

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Demco Trailer Brakes - Hydraulic Drum Brakes - 40716-15 Review

Speaker 1: Today we're gonna take a look at the Demco 10 inch left hand/right hand side free backing hydraulic drum brake assembly for 3500 pound axles, with a galvanized finish. Now, these are marine grade hydraulic drum brake assemblies. They're great for boat trailers. They are designed for use with surge type trailer brake actuators. These assemblies are a sturdy corrosion resistant field construction. If you notice the back is ...

they use galvanized backing plates on it. The spring hardware is all stainless steel. And the wheel cylinder is a zinc plated wheel cylinder. It is a universal wheel cylinder, you can see it has a single plunger design. Now, these brakes are free backing design.

And what that basically means is it'll let you back up without engaging the trailer brake, even if your actuator is activated.And the way they do that is the primary shoe right here is a riveted fall away brake shoe that'll only anchor on the drum when the brakes are engaged and if the trailer is moving forward. In a free backing design assembly, you can always tell by the primary shoe will be a "D", have a "D" design to it. You can see this one, same way. These are manual adjustment brakes. You have to adjust them right down here where the adjustment gear is.

So, you just turn that gear and it'll adjust either in or out. And it does require a periodic manual adjustment.Now, the mounting hardware to install these is sold separately, we do list them on our website. And they're usually listed on this product page as a related product. Now the size on this, they are 10 inches by 2.25 inches. And what that size would mean is the 10 inches is the diameter, that's measured from this shoe all the way over to that shoe.

So if we put the ruler on it, there's your 10 inch diameter. The 2.25 inch would be the width of the pad on the brake shoe. There's your 2.25 inch width. They do have a brake mounting flange bolt pattern of four lugs, four on four inch bolt pattern. The wheel size that'll work on these is 13 inch, 14 inch, and 15 inch. And they are designed for axles rated up to 3500 pounds. So each assembly would be rated at 1750 pounds. And when they're used of both on the same axle, it'll meet the 3500 pound axle rating.Does include both the driver side and passenger side brake assembly. And the last thing I just wanna show you is how to tell what assembly goes on what side. Now, on a new assembly, it'll always have a sticker that'll say right hand or left hand on it. But, if you didn't have that sticker, the best way to tell is just look at the length of the brake pad on the shoe. This pad goes from here to here. This one's from here all the way to here. This is the longer pad. This is the shorter pad. The shorter pad is always your primary shoe. That's made to face the front of the trailer. So that'll tell you that this one is for the right hand passenger side assembly. And this one here is the shorter shoe. And this is gonna go this way, so this'll be the left hand driver side assembly.But that should do it for the review on the Demco 10 inch left hand and right hand side free backing hydraulic drum brake assembly for 3500 pound axles, with a galvanized finish.

Customer Reviews

Demco Hydraulic Brake Kit - Free Backing - Galvanized - 10" - Left/Right Hand Assemblies - 3.5K - 40716-15

Average Customer Rating:  4.9 out of 5 stars   (40 Customer Reviews)

Free-backing, driver's-side and passenger's-side brakes won't engage when you reverse, even if your actuator is activated. Galvanized steel resists rust, making the assemblies great for boat trailers. Fit 13" to 15" wheels.

- 40716-15

Everything looked great when package was received. New brake assemblies bolted right up to the factory flanges and worked perfectly after bleeding the system. 423132

- 40716-15

24 yr old boat trailer brake cylinder finally fails. Brake shoes very thin. Every thing rusty and dirty. I look at cylinders only, pads only, then found these! Everything new at reasonable price and delivered on time. First trip found them to be smooth in operation. did not jam on at the last minute like the old ones did. THANKS etrailer. 666529

- 40716-15

Very impressed with the speed of shipping. Wow! Very happy with the parts. 678618

- 40716-15

Hey George just got done installing your brake system on my Carkins dual axle boat trailer, what are nice product they went on beautiful no issues whatsoever extremely satisfied following is a picture of before and after , I just bought the boat and trailer and could not believe the condition of the brakes 376565

- 40716-15

2000 ez loader trailer complete brake job. 2 axle torsion suspension. All 4 axles . I ordered 4 complete brake /backing plate assemblies and 4 new hubs. My complete order showed up on time afew days later. After I got the trailer and boat jacked up and started to take things apart I overlooked not ordering the transitional flexible brake lines that go from the hard lines into the back of the brake assembly. After traveling for 30 minutes to a hydraulic brake line shop to have lines made up they told me they did not have the fittings I really needed these lines to get this job done for the weekend to get the boat out on the water. So I called etrailer and was connected to Tiffany who I must say provided the best customer service I've ever experienced she worked with me on getting the correct items and set up next day rush shipping. She even personally made sure that my order got out the door and called me personally to let me know . There aren't too many companies that goes to that length to serve their customers. The next day at 10 a.m. the were delivered to my front door. (From half way across the United States ) . I was trilled to say the least. Thank you etrailer and a special thank you to Tiffany. In customer service for your personal attention and follow up regarding my order. 569949

The complete brake and line replacements our working great 1 year later. And I put alot of miles on my trailer both to salt water and fresh water.
Steven - 09/29/2019


- 40716-15

Perfect fit, I had them installed in 20 minutes. Super fast delivery. 491616

- 40716-15

I bought these right and left hydraulic brake assemblies for my boat trailer at a great price. I received my order one day earlier than promised. Etrailer.com really rocks to satisfy it’s customers. They provided an awesome tracking link for me to review my order’s shipping progress. This is the best tracking link that have ever experienced. Both complete brake assemblies fitted perfectly in place of my old assemblies. On each Brake assembly, I just had to remove the 4 mounting bolts from the axle flange and the hydraulic hose. Then install the new complete brake assembly, tighten the 4 mounting bolts and makeup the hydraulic hose.. This made this brake job a breeze! It was a pleasure doing business with you. Thanks Etrailer.com! 749507

- 40716-15

my new brakes arrived in 48 hrs, nice! Left side went on like a breeze. The video on website made me feel like I was getting the right part the first time. Ill tackle the right side tomorrow 746017

- 40716-15

Very pleased with these folks, shipping was very quick and the parts are top notch. 739194

- 40716-15

Very happy with purchases 738930

- 40716-15

Went on perfectly. They’ve been operating flawlessly for over a year now. 734849

- 40716-15

Arrived next day exactly what was descr ibed 723036

- 40716-15


- 40716-15

I couldn't be happier with the company and the product. Great website and good customer service. 714918

- 40716-15

Good quality. Was easy to install. Third time I have purchased at etrailer always a good experience. Very fast shipping. 706308

- 40716-15

Product arrived exactly when promised, opened the box and was very pleased with what I saw. Very nice quality and workmanship, everything looked perfect. It was about an hour and a half worth of work replacing the old brakes in my 1991 Escort boat trailer, and they work perfectly! Very happy! 696416

- 40716-15

Brake assy. for my boat trailer fit perfect.Fast delivery and great customer service. 694987

- 40716-15

Brakes are asgood as new, product is working great. I have tandem axels and the brakes are working excellent. 688516

- 40716-15

part arrived undamaged. Was an exact match to my old brake. Assemble went smooth. Brakes on my tandem axle boat trailer work better than ever. Price was good. Quality was better than the original parts. 679114

- 40716-15

Great replacement. Took off the old crud and cleaned up the mount. The new assembly bolted right on. 667705

- 40716-15

Fast shipping and excellant product. 664172

- 40716-15

Exemplary all around..ease of ordering; prompt delivery; bolt-on installation; follow-up inquiry..Wish all my transactions were as professional.. Only downside.. didn't order everything needed from e-Trailer..will not make that mistake again.. Grateful..Satisfied customer..Thank You! 661896

- 40716-15

Great communication and parts came quickly with free shipping. Brakes were easy to install, and great quality. Great experience! 654767

- 40716-15

Slid right into place and worked perfectly! I could not be happier. 640925

- 40716-15

Brakes are working great 635427

Show More Reviews

Ask the Experts about this Demco Trailer Brakes

  • Recommended Brake Assemblies for Karavan Boat Trailer with 3500 lb Axle
    For your brake assemblies, I recommend the Demco Hydraulic Brake Kit - Free Backing - Galvanized - 10" - Left/Right Hand Assemblies - 3.5K # 40716-15. These galvanized assemblies will work very well for saltwater or freshwater use, resisting corrosion. The free backing design allows you to back up without using the lockout on your coupler. This will absolutely fit your 3500 lb axle. For your Bearing Buddies, bearings, and seals, you very likely have the standard size 84 spindle...
    view full answer...
  • Ways to Determine Axle Capacity of Trailer
    There's a few ways to determine trailer axle capacity. You can check the axle for a label which will have it's capacity and length listed, it might be listed on the plate of the coupler that also has the VIN, or you can measure the diameter of the axle. If the axle diameter is 2-3/8 inches then that would indicate you have a 3,500 lb axle. If the drums of your hubs are 10 inch in diameter and 2-1/4 inches deep that would also indicate this too and would mean that the brake assembly set...
    view full answer...
  • Is Galvanized Coating Best for Salt Water Application for Boat Trailer Brakes
    The Galvanized Demco Hydraulic Brake Kit # 40716-15 is definitely the best coating that you can get for corrosion resistance. The other coatings are basically just different levels of powder coats while galvanized resists salt water much better. I do recommend rinsing your boat trailer off as well to help extend the life of the various components.
    view full answer...
  • Recommended Replacement Hydraulic Brakes with 10-Inch Diameter for a Boat Trailer?
    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...
    view full answer...
  • Is Demco Hydraulic Brake Kit # 40716-15 Sold As Pair or Individually
    The Demco Hydraulic Brake Kit # 40716-15 that you referenced is sold as a set. This gives you both assemblies you'd need for a single axle. So since you have a single axle trailer you need to just order a quantity of 1.
    view full answer...
  • Hose Fitting Needed For Demco Hydraulic Brake Kit # 40716-15
    The Demco Hydraulic Brake Kit # 40716-15 uses a 3/16" Inverted Flare fitting to connect to the brake lines. If you need new mounting hardware for your brakes you can use the Redline Kit for 10" Brake Assemblies # BRKH10A .
    view full answer...
  • 3,500 lb Free-Back Hydraulic Brake Assembly Recommendation for Trailer
    For free backing, hydraulic drum brake assemblies that are 3,500 lb capacity we have assemblies that are 10 inch by 2-1/4 inch like the part # AKFBBRK-35-D which comes with assemblies for both sides of the trailer. We don't have anything that's 1-3/4 inch wide for a 3,500 lb axle.
    view full answer...
  • Recommended Replacement 10 Inch Hydraulic Drum Brakes for 1985 EZ Loader Boat Trailer
    The Atwood Brake Actuator AT82543 referenced in your question is compatible with any trailer that has hydraulic drum brakes. Uni-servo wheel cylinders are found on certain hydraulic brake assemblies. If an assembly has them, this basically means that they are not free-backing assemblies, as they feature a single-pushrod wheel cylinder that will retain about 20 percent of their braking ability in reverse. If your trailer has a 3,500 pound axle, I recommend looking at the Demco Hydraulic...
    view full answer...
  • Are There Galvanized Trailer Hub/Drums for Travel Trailers
    We do have galvanized trailer hub/drums available for travel trailers. For example we have the part # 8-247-50UC3 which fits the very popular 3,500 lb trailer axles and has a 5 on 4-1/2 inch bolt pattern. If you have a different need for a hub/drum let me know and I'll see what we have that would be best option.
    view full answer...
  • Is A Brake Flange With A Bolt Spacing Of 2-3/4" The Same As A Brake Flange With Spacing Of 2-7/8"
    Yes, the Demco Hydraulic Brake Kit - Free Backing - Galvanized part # 40716-15 will fit a 3,500 lb trailer axle with a brake mounting flange dimension of 2-7/8". The dimensions of the brake mounting flange from bolt hole to bolt hole is an industry standard, however some companies such as "Demco" refer to this measurement as a 2-3/4 instead of the more common 2-7/8". The actual dimension is really more like 2-13/16", but different brake manufacturers will round to either 2-3/4" or 2-7/8"....
    view full answer...
  • Replacement 10-Inch Galvanized Drum Brakes for Boat Trailer with 14-Inch Wheels
    If you cannot find a sticker or plate on your boat trailer axle you can still get in the ballpark on its weight rating based on the brake dimensions. All of our 10 x 2-1/4-inch drum brakes, both electric and hydraulic, that work with 14-inch trailer wheels will be rated for axle capacities from 3500-lbs on the low side up to 4400-lbs on the high side. The vast majority of these brakes are for 3500-lb axles so odds are good that is your rating. All brakes are shown on the linked page. Do...
    view full answer...
  • How To Find the Axle Capacity of a Square Tube Axle To Determine Correct Braking Assemblies
    The process to measure the axle diameter to determine an approximate weight capacity does not apply to square tube axles. Therefore, you must find the axle tag if present and reach out to the axle manufacturer with the serial number if the capacity cannot be found on the axle tag. If the axle tag is not present then you will need to reach out to the trailer manufacturer. If the reason you need to determine the axle capacity is for choosing a set of braking assemblies then this is not...
    view full answer...
  • What is Needed to add Brakes to Boat Trailer?
    To determine the brake assemblies that will fit your trailer, you would need to know your axle's weight capacity, the size of your wheels, your mounting flange bolt pattern and the inside diameter and depth of your hub. Depending on the type of brakes you want, different parts will be needed. For example, to add hydraulic drum brakes you would need a hydraulic drum brake actuator, a brake line kit and the brake assemblies. I've left a link to our page with our selection of brakes for...
    view full answer...
  • Brake Assembly Replacement Recommendation for 1994 Eagle Boat Trailer
    The brake assemblies part # 40716-15 that you referenced are exactly what you need. The size matches, the capacity is adequate, and the bolt pattern matches as well! I attached a review video for this brake assembly set for you to check out as well.
    view full answer...
  • Comparing Different Hydraulic Trailer Brakes for Boat Trailer
    Essentially yes, all of them will work for your trailer assuming you have 3,500 pound axles and a 4 bolt mounting flange. However, there are some differences between the brake assemblies you mentioned. The # AKFBBRK-35 are free-backing brakes, meaning they will not engage when reversing with your trailer. If your trailer has a reverse lockout on it then this feature is not necessary. They're coated with an e-coat used for corrosion resistance. The Demco brakes # 40716-15 are galvanized...
    view full answer...
  • Difference Between Demco 10 inch Drum Hydraulic Brakes and etrailer.com Brand Brakes
    The big differences is basically pricing and brands. The part # AKFBBRK-35-D is a pair of Dacromet coated drum, hydraulic brakes that are free-backing. The part # 40716-15 is essentially the same thing buy made by Demco. The etrailer brand is going to cost less since it's our brand and there's not as much markup so it's the better deal. Now the part # 40716-15 is basically just the part # 40716 and # 40715. What doesn't make much sense though is the pricing difference. It would seem...
    view full answer...
  • How To Tow a Boat Trailer That Has A Reverse Lockout Using a 2020 Hyundai Palisade
    There are a few options here for you to tow your boat trailer and be able to backup with the trailer attached and the brakes not locking up. The most cost effective option is a wiring adapter, the Tow Ready 4 Pole to 5 Pole Trailer Wiring Adapter part # 20036. The downside of this option is that you have to splice into the factory reverse light wire on your vehicle. If you don't want to do this then you can either install a trailer coupler with manual lockout like the Brake Actuator with...
    view full answer...
  • Recommended Replacement Brake Assemblies For Eagle Trailer Drum Brakes
    We have a few product options to replace your brake assemblies. I recommend the Hydraulic Brake Kit - Uni-Servo - Free Backing - Dacromet - 10" - Left/Right Hand - 3,500 lbs # AKFBBRK-35-D. This will give you both assemblies for one axle. These are free-backing so you can back up with your trailer without engaging the trailer brakes. They are marine-grade and designed for boat trailers. The dacromet coating offers corrosion resistance. Another really nice option is the similar brake...
    view full answer...
  • Can Mounting Studs be Removed from Hydraulic Brake Assemblies AKFBBRK-35-D
    The four mounting studs on Hydraulic Brake assemblies # AKFBBRK-35-D are not removable. These are press-fit for a permanent installation. For a similar brake without studs you can use Demco kit # 40716-15. These brakes are also free-backing galvanized finish left- and right-hand brakes for 3500-lbs axles.
    view full answer...
  • How To Add Surge Brakes to the Timbren 2,200 Lb Axle-Less Trailer Suspension System
    It sounds like you are referring to surge brakes in which case I do have an option for you to add these to the Timbren Axle-Less Trailer Suspension System part # ASR1THDS03. In order to do this you will need the Demco Hydraulic Brake Kit part # 40716-15 and the Dexter Trailer Hub and Drum Assembly part # 84546UC3-EZ (2). The rest of the parts you will need are brake lines, the Titan Hydraulic Brake Lines and Fittings part # T4829900 and a surge brake coupler, the Demco Hydraulic Brake...
    view full answer...

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