bing tracking image
  1. Accessories and Parts
  2. Demco
  3. Trailer Brakes
  4. Hydraulic Drum Brakes
  5. Brake Assembly
  6. 10 x 2-1/4 Inch Drum
Demco Hydraulic Drum Brake Assembly - Free Backing - Galvanized - 10" - Right Hand - 3,500 lbs

Demco Hydraulic Drum Brake Assembly - Free Backing - Galvanized - 10" - Right Hand - 3,500 lbs

Item # 40715
Our Price: $73.06
You Save: 40%
Accessories and Parts
Shipping Weight: 10 lbs
Add to cart
In Stock
Demco Trailer Brakes - 40715
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

Customer Photos

Need help with installation?
Locate installers near me
Free-backing, passenger's-side trailer brake assembly won't engage when you reverse, even if your hydraulic actuator is activated. Galvanized steel resists rust, making the assembly great for boat trailers. Mounting flange has 4-bolt pattern. 1-800-940-8924 to order Demco accessories and parts part number 40715 or order online at Free expert support on all Demco products. Great prices and Fastest Shipping for Demco Hydraulic Drum Brake Assembly - Free Backing - Galvanized - 10" - Right Hand - 3,500 lbs. Accessories and Parts reviews from real customers.
  • All Info
  • Reviews (166)
  • Q & A (0)
  • Photos

Demco Accessories and Parts - 40715

  • Trailer Brakes
  • Hydraulic Drum Brakes
  • Brake Assembly
  • 10 x 2-1/4 Inch Drum
  • Demco
  • RH
  • 3500 lbs
  • Free Backing

Free-backing, passenger's-side trailer brake assembly won't engage when you reverse, even if your hydraulic actuator is activated. Galvanized steel resists rust, making the assembly great for boat trailers. Mounting flange has 4-bolt pattern.


  • Marine-grade hydraulic drum brake assembly is great for boat trailers
    • Designed for use with surge-type trailer brake actuators
  • Sturdy, corrosion-resistant steel construction
    • Galvanized backing plate
    • Stainless steel spring hardware
    • Zinc-plated wheel cylinder
  • Free-backing design lets you back up without engaging the trailer brake, even if the actuator is activated
    • Riveted, fall-away brake shoe only anchors on drum when brakes are engaged as trailer is moving forward
    • Periodic manual adjustment required
  • Mounting bolts sold separately
  • Made in the USA


  • Configuration: right hand (passenger's side)
  • Dimensions: 10" diameter x 2-1/4" thick
  • Mounting flange bolt pattern: 4 on 4"
    • Measurement between center of mounting hole to center of mounting hole: 2-3/4"
    • Diagonal measurement bewteen mounting holes: 4"
  • Wheel size: 13" - 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 Brake with Fall-Away Shoe

This Demco free-backing brake assembly 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, the 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.

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

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Demco Hydraulic Drum Brake Assembly - Free Backing - Galvanized - 10" - Right Hand - 3,500 lbs - 40715

Average Customer Rating:  4.8 out of 5 stars   (166 Customer Reviews)

Free-backing, passenger's-side trailer brake assembly won't engage when you reverse, even if your hydraulic actuator is activated. Galvanized steel resists rust, making the assembly great for boat trailers. Mounting flange has 4-bolt pattern.


The right and left brake assemblies for my boat trailer arrived quickly and in good shape. The instructional video helped ensure my bolts were oriented properly to allow the brake cylinder to move and it was a relatively easy swap once I got the rusted old assembly removed.



A year later and brakes are still working well. Definitely pleased with this purchase.

Etrailer Expert

Mike L.


@Ken We're happy to hear that the # 40715 brake assemblies are working well for you!


Product is fine, but customer service (pre-sales) and shipping times are so far gone from e-trailer of years past. Site indicated two day delivery, seven days later the item was received - but not complete. Still waiting for another part of the same order.

Etrailer Expert

Katrina D.


It says in our system that both of these orders have arrived on the 14th and the 15th. Can you please confirm whether you have actually received them both?

Chris D.


Yes, I received them. Is two day shipping no longer a thing? I don't recall an order taking so long to process pre-shipping.

Etrailer Expert

Katrina D.


Yes, two-day shipping is still a thing, depending on the time of day that the order is placed and what shipping method is used. It looks like all of your orders have shipped via Free Shipping and seems that some of them shipped via US Mail. I would highly recommend using expedited shipping if you are needing something by a specific time.


Great company to deal with. Impressive and Professional. Very reasonable in pricing.
Products purchased; trailer Drum and hydraulic surge brakes. Fitted and Work's perfectly. Sad to see everything is made in China.


Item is as advertised. It was quicker easier and cheaper to replace the whole backing plate assembly. If I had replaced brake shoes, wheel cylinder, and spring kit I would have spent more money & time. I will use etrailer for all of my trailer needs. etrailer even upgraded my shipping at no extra charge. Thank you for the great service.


The brakes on my 30-year-old boat trailer locked up and would not release. I purchased a set of these Demco brake drum assemblies and installed them myself. It was my first attempt at repairing a hydraulic surge brake system. Before beginning the remove and replace process I watched a “how to video” on the etrailer website. Everything went well, the system now functions as required.
Over the years I have purchased a lot of product from etrailer. I have received excellent product and service everytime.



After one year the complete brake system is working perfectly.


I have a 1996 E Z Loader Boat trailer that needed a brake job. Couldn't get any satisfaction calling around to find parts until I found the etrailer web site. Everything I needed was laid out easy to find and the prices were fantastic. I compared buying one bearing seal at an auto parts store and found I could do the bearing, race and seal for less on etrailer. They shipped everything as I had ordered and they actually arrived earlier than expected. My mechanic said it was one of the easiest brake job that he ever had to do due to the fact everything was preassembled. I have passed this site on to all my Bass fishing buddies.

Ron C.


Best bang for your buck. Have not had one issue with my new trailer brakes. Hope these last another ten years as I know the trailer wont.


These brake parts were easy to install after watching the videos at I installed brakes on both wheels on my boat trailer along with new seals and they work great. I've only taken a test drive, but the new brakes really help.

Steven S.


Very satisfied with these brakes. They grab a little when first coming out of the water, but that goes away after the first stop.


Bought a set of these and a master cylinder for my single axle boat trailer..and now I have surge brakes. Yea!

Products were of excellent quality and exactly as displayed and shipping was prompt and the order process was a breeze!

Great company to do business with and the prices are excellent too!

Lew A.


It has been a year and I still have great surge brakes..thank you very much!


Replaced original Dico brakes on trailer for 20' Maxxum without a hitch.
Buying the complete assembly is the way to go. Thanks!

Dean H.


Brake rebuild has been a success over the long term.


I spent a lot of time trying to clean the grease and dirt off my old ones to try to salvage them after replacing bearings and leaky seals that made a big mess out of my brakes. And, removed worn out shoes by messing with all the springs, before I found these, the whole assembly put together already, and galvanized. I bought four and simply installed them with four bolts. Also added a new actuator, tested the brakes, and they work great. Installed on a 1991 Tracker trailer. Like new again, and saved hundreds doing it myself. Wished I knew about this product sooner.


This brake assembly bolted right up and installed in minutes. Much faster and easier (and more cost efficient) than replacing just the failed parts of the original brakes (frozen wheel cylinder and shoes). The "free backing" feature doesnt seem to work all that well. I can feel a heavy amount of drag in reverse and leave tire marks from my trailer all the way up my sloped driveway unless I manually engage the reverse lockout on my actuator. I purposely bought this set so I wouldnt have to do that anymore.


Product fit my trailer perfectly. Was exactly the same as the assembly it replaced, just new and working. The pads on my old assembly were worn down, and the wheel cylinders were seized.

One thing that would be nice is some advice on how to bleed this hitch actuated trailer brakes. It's not an easy job, being that a great deal of force is required at the hitch in order to push the fluid through. (Being that it is meant to be actuated by the trailer's weight.

I used a piece of lumber propped on the pavement to leverage the hitch in to push the fluid through. Wondering if there might be a better way to do it . . .

Great product, fast delivery!


I used to have to stop before going down a hill to disengage my brakes so I could stop barely, then back up hill into my driveway. These brakes work great. I would recommend them and also I would recommend the hub and drum assembly. By the time I put new bearings and races in and turned the drums I wish that I would have bought new ones for my trailer that sees a lot of saltwater.


The hydraulic drum brakes with backer plates, I ordered came on time and fit great. I also installed new bearings and they fit good too. I will use them again when I need more parts.


This part fit 100%. I got the best price from etrailer and I'm so happy that I could install it easily. My brake cylinder was leaking and this was the best way to go to replace the whole unit. I will be ordering the other side this year. Thanks etrailer. PS I'm from Canada and shipping wasn't a problem. I live in Vancouver aND ordered it to blaine aND it arrived really fast. Thanks again


Hydraulic trailer drum brakes. Received within a few days. Easy to install, not that complicated. Needed a second person to help bleed the brakes.


I was satisfied with the drums and brake units supplied by Etrailer. The wheel bearings were junk so I trashed them, and repacked the Timkin's that were already on the trailer.

I was pleased with the support I received from Etrailer ensuring the correct items were ordered to avoid returns.


Received the brake assembly, installed it with no problems. Easiest brake job I have ever done, 4 bolts attach the brake line, adjust the brakes and you are done. I had a question on the flange bolt spacing. The 4 on 4" is a diagonal measurement. If you look at the picture of the brake assembly above the spacing of top left to top right is 2 7/8", diagonal top left to bottom right is 4" This fit my application perfectly.


Perfect replacement for my old rusted boat trailer brakes. Assembly was straight forward. Brakes release well in reverse. All I could ask for.


I am so glad I found the etrailer website. The product fit perfectly, was simple to mount, the shoes were nearly adjusted out of the box and the price is too good to be true. I would recommend this to anyone.


Excellent quality. Installed easy with all 4 brakes assembly. Confidentiality!!!!



No issues


This product was reasonably price so I purchased it instead of piece parting it. It made the job much simpler. The only thing we have to do at the one year mark is to check the adjustment I would recommend this product to anyone thinking of rebuilding their trailer brakes.


These brakes are a breeze to install! I put them on my boat trailer which I launch in salt water, so it would have been nice to have a washout port (the reason I didn't give them an excellent rating). The price is good and the install is easy, so if I get a couple years out of them I'll be happy.


Not only is replacing the entire assembly easier than the shoes and wheel cylinder, it is cheaper. Saved lots of time. Thanks for great service.


Great product for boat trailers, made renewing my brakes easy.

Show More Reviews

See what our Experts say about this Demco Accessories and Parts

  • How to Pick Out Replacement Hubs for a 1980 Shore Landr Trailer
    In order to pick out the correct hub assembly for a trailer you are going to need know a few key pieces of information. The first thing you will need to know is the bolt pattern of your hubs. This is so you get a hub that is compatible with your wheels. I attached an FAQ article on determining bolt pattern for you to check out. Next thing you will need to know is what spindle you have on your trailer. In order to do that you can either get the inner and outer bearing numbers from a hub...
    view full answer...
    Image 1 for
  • Determining If Surge Brake Actuator Has Lockout or If Brakes are Free-Backing
    The only way to turn a surge brake actuator "off" is to engage a lockout on the actuator. Some actuators have manual lockouts, others have electric lockouts, and some have no way to lock out the actuator. Typically, free-backing brakes are used with actuators that have no lockout. As long as the trailer brakes engaging when your tow vehicle is stopping, the brakes are working correctly. I have attached photos showing a manual lockout and electric lockout to help you determine if your actuator...
    view full answer...
    Image 1 for Image 2 for
  • Does Demco Hydraulic Brake Assembly # 40715 Include the Brake Drum
    The # 40715 Demco Rt. Hand 10 inch brake assembly is sold separately from the brake drum. If you'd care to reply with the inner and outer bearing reference numbers, along with the axle capacity and the wheel bolt pattern (see help article about how to determine this), I'd be happy to make some recommendations for you.
    view full answer...
  • Comparing Single Serve and Free Backing Functions on a Demco Free Backing Brake Assembly
    Single serve refers to the wheel cylinder in a hydraulic drum brake assembly. It is an entirely separate component from the free backing option. A single serve, or uni-servo, wheel cylinder uses a single plunger to push the brake shoes against the drum. When you are backing up, the wheel cylinder and the brake shoe springs work against each other. The dual spring and fall-away shoe design of the Demco free backing brakes allows the shoe to overcome the pressure from the wheel cylinder...
    view full answer...
  • What Bearings Should Be Used with a Dexter Hub
    As long as you find the correct bearings for the hub you should be fine. If you wanted to email me back with what Dexter hub/drums you bought I could help you pick out the correct parts. Or if you search the part number and find the product page the bearing numbers will be listed in the description.
    view full answer...
  • Mounting Drum Brakes to an EZ-Loader Trailer with 4-Bolt Brake Mounting Flange
    If you are wanting to install your brakes on your EZ-Loader trailer, you will need brake mounting flanges with a 4 bolt pattern that matches the bolt pattern of your brake assemblies. We do carry some brake mounting flanges, but we will need to know the diameter of your axle or spindle shaft to determine if we have a brake mounting flange that will fit your trailer. The brake mounting flanges will need to be welded on square, so we recommend having a qualified professional with trailer...
    view full answer...
    Image 1 for
  • Recommended Brakes For Boat Trailer With Surge Coupler And 3500-Lb Axle
    There are quite a few brake assemblies that will work with your EZloader trailer. It helps when you give the information you provided when choosing a system. I recommend using free-backing brakes like the Demco Brakes. For the left hand(driver side) you would need part # 40716 and for the right hand I recommend part # 40715. These do not engage when backing up so they are great for a boat trailer. These brakes do have a 4-bolt brake flange.
    view full answer...
  • What is the Mounting Hole Pattern for Galvanized 10 Inch Marine Trailer Brake Assembly 40715
    The Demco hydraulic drum brake assembly, # 40715, mounts to a standard 4-bolt mounting flange like # 4-35. The bolt holes are 2-7/8 inches apart on center. If measuring diagonally from a top hole to a bottom hole it is 4 inches on center.
    view full answer...
  • Are All 4 Bolt Trailer Brake Mounting Flanges the Same Bolt Pattern
    Yes, the 4 bolt mounting pattern that the Titan Galphorite Free-Backing Hydraulic Trailer Brake Assembly # T4423400 and the Demco Hydraulic Drum Brake Assembly # 40715 have is the same 4 on 4 inch bolt pattern. Basically all 4 bolt brake mounting flanges are the exact same 4 on 4 inch pattern.
    view full answer...
    Image 1 for
  • How to Select Replacement Hydraulic Drum Brake Assembly for Calkins Boat Trailer
    You can choose a correct replacement hydraulic drum brake by matching up a few characteristics to yours. You need to match up axle weight capacity (usually found on a sticker or plate on the axle), the drum diameter and width, and your brake mounting bolt pattern. You can click on the link provided to see our main page for hydraulic drum brakes. First, click on the axle rating, then your drum size. Most of our brake assemblies, such as Demco Hydraulic Free Backing 10 x 2-1/4-inch brake...
    view full answer...
  • Trailer Brake Assembly Replacement Recommendation after Water Contamination
    We sell several wheel cylinders that you could use as replacements. Most likely that is all you would need to replace on your assemblies. You will want to check out the link I attached to see all of the ones we carry so that you can pick out the correct one. Or, it would be a good time to replace your current brake assemblies. To pick out the correct brake assemblies for your trailer you need to know a few things. You will want to measure the inner diameter of your hub/drums and the...
    view full answer...
  • Picking Out Brake Assemblies for 2008 Palomino Sabre Travel Trailer
    I can help you find the right assemblies, but I do not know exactly which ones you have on your 2008 Palomino 25RS. To pick out the correct brake assemblies for your trailer you need to know a few things. You will want to measure the inner diameter of your hub/drums and the depth of the drums to determine what brake assembly dimensions you need. For example the part # 23-468-469 is a 10 inch by 2-1/4 inch thick brake assembly set. I attached an install video for this kit for you to check...
    view full answer...
    Image 1 for
  • Can One Set of Hydraulic Drum Brakes Provide Enough Stopping Power for a Tandem Axle Boat Trailer
    If your boat trailer came equipped with hydraulic drum brakes on both axles, it is best to keep both sets in working order, but if this is the route you prefer you'll want to put the new brakes on the rear axle where most of the boat's weight will be concentrated. I linked our main page for hydraulic drum brakes. You can use the filters on the page to select your overall axle capacity (both of your current axles' capacities added together) to see if we have brakes of the appropriate rating,...
    view full answer...
  • Recommendations for Hydraulic Brake Assemblies on a 1993 Trail Rite 3500 Pound Boat Trailer
    Whether you ultimately decide to go with free-backing or not, I would recommend getting galvanized brake assemblies. The springs are stainless steel and the plates are galvanized which will help them hold better since you have a boat trailer and the brake assemblies maybe exposed to more water. I like the free-backing systems better. They will make backing down a boat launch a bit smoother, especially if someone else is backing the vehicle in while you are in the boat pulling off the trailer....
    view full answer...
  • Free-Backing 12 x 2 Drum Brake Drags When Moving Forward on Karavan Boat Trailer
    Thank you for providing the photo of the left-hand brake assembly on your boat trailer. The bolt that attaches your actual brake shoe to the shoe lever arm should be tight, but we do not have an actual torque specification. It is intended that the bolt provide a pivot point for movement between those two parts. After examining your photo and comparing it to all of the free-backing 12 x 2 brake assemblies we offer I noticed that one of the springs on your brake appears to be in an incorrect...
    view full answer...
    Image 1 for
  • Can Surge Coupler/Actuators Be Converted from Drum to Disc Brake Operation
    Surge couplers for drum and disk brakes use different master cylinders that operate at different pressures, lower for drums and higher for discs. It is possible to swap out the master cylinder in a surge coupler to convert it from one type of operation to the other. Depending on the number of brake assemblies, trailer length, etc, larger brake lines are sometimes also called for with disc systems. It sounds like you have free-backing drum brakes like # 40715 on the trailer now, which allow...
    view full answer...
  • Does Brake Assembly part # 40715 Come with Lock Nuts and Washers
    The brake assembly part # 40715 does not come with lock nuts and washers. For that we have the part # 6-17 for the nut and part # 5-8 for the lock washer.
    view full answer...
  • Hydraulic Drum Brakes Recommended with Demco Hydraulic Trailer Brake Actuator
    With a broken master cylinder and shock, replacing the actuator is a great plan. The Demco Hydraulic Trailer Brake Actuator # DM72VR will work great with the Demco Hydraulic Drum Brakes # 40715 and # 40716 that you referenced. Since the actuator # DM72VR doesn't have a reverse lockout, the free-backing brakes will work great for you. Usually, free-backing brakes are more reliable than reverse lockout couplers. I have attached an installation video of the Demco Hydraulic Trailer Brake...
    view full answer...
  • What Braking Assemblies do I Need for Karavan Tandem Axle
    If the bolt pattern on your axles, for the backing plate, is 2-3/4 inch on center , both of these braking assemblies would fit your 10 inch x 2-1/4 inch trailer brake assemblies. Part # 40715 and # 40716 are what I would recommend. These are the left and right hand side brake assemblies. Since you are going to be backing up an incline you want the least amount of reverse braking which is why I recommend these over the other. The shoes for these assemblies are part # BP04-126. The part...
    view full answer...
  • Replacement Electric Trailer Brakes for Snowmobile Trailer
    To determine the correct replacement electric brakes you will need to know the weight capacity of your axle and then measure the inside diameter and width where the pads from the brakes touch. If your axles are 3500 lbs and you get 10 inches by 2-1/4 inches AND the brake mounting flange has a 4 bolt pattern then assembly # 23-469 for the right and # 23-468 for the left will fit. The best brake assemblies as far as resisting corrosion due to moisture are hydraulic brakes, which are used...
    view full answer...
  • Replacement Drum Brakes for 2000 Maxum Boat Trailer
    We carry both hydraulic and electric drum brakes for trailers in a range of sizes and for various axle weight ratings. We can help you select new brakes. The things you'll need to confirm are the axle's weight rating, the drum size, the type of brakes (electric or hydraulic) and the mounting bolt pattern of the brake flange. Axle capacity is usually listed on a plate or sticker right on the axle itself. Drum size can be determined by pulling one of the hub/drum assemblies and measuring...
    view full answer...
    Image 1 for
  • Replacement Hydraulic Drum Brake Assembly Recommendation to Replace Rusty Assemblies
    For the price of replacement brake pads and shoes it's almost always a better solution to go ahead and just replace the entire brake assembly. And in your situation with the current condition of your assemblies I would strongly recommend you do that based on how much rust is there. In order to pick out assemblies you need to know the diameter of the assemblies and the width of the brake brake pads. I can tell by the pics you have the standard 4 bolt mounting flange. The most common brake...
    view full answer...
    Image 1 for Image 2 for
  • How to Pick Out Surge Brake Hub/Drums and Assemblies for Trailer
    So the easiest way to replace the components you mentioned would be with new hub/drums and new brake assemblies. To do that I'd need to know a few key pieces of info. The bolt pattern on the hub where the wheels attach, the bearing numbers out of the hub or the dimensions where they ride on the spindle. With that info I can get you the correct hub drum and from there know which brake assemblies you'll need. I attached a link to this page that details this process as well.
    view full answer...
    Image 1 for
  • What Information is Need to Find Parts to Switch from Hydraulic to Electric Drum Brakes
    We would need to know how big the current brakes are. 10x2-1/4 or 12x2 etc. Sometimes you can re-use the drums from hydraulic brakes for electric brakes, sometimes not. If you are going to go ahead and replace the drums, we would need to know inner and outer bearing numbers. These are stamped right on the bearings. We would also need the bolt pattern of the drums. I have added a link to a wheel page that shows you how to measure bolt pattern at the bottom. Wheel diameter is important as...
    view full answer...

< Previous

Do you have a question about this Accessories and Part?

Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Patrick B
Expert Research:
Patrick B
Employee Michael H
Expert Research:
Michael H
Employee Jameson C
Expert Research:
Jameson C
Employee John H
Expert Research:
John H
Employee Adam R
Expert Research:
Adam R
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Victoria B
Expert Research:
Victoria B
Employee Lindsey S
Updated by:
Lindsey S
Employee Adele M
Updated by:
Adele M
Employee Laura H
Updated by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Jeff D
Installed by:
Jeff D

At we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.

Product Experts Available Now!
Call 1-800-940-8924