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Demco Hydraulic Drum Brake Assembly - Single Servo - Galvanized - 10" - Right Hand - 3,500 lbs
Demco

Demco Hydraulic Drum Brake Assembly - Single Servo - Galvanized - 10" - Right Hand - 3,500 lbs

Part Number: 18787
In Stock
$71.32
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Passenger's-side hydraulic trailer brake assembly features a single-plunger design. 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 18787 or order online at etrailer.com. Free expert support on all Demco products. Great prices and Fastest Shipping for Demco Hydraulic Drum Brake Assembly - Single Servo - Galvanized - 10" - Right Hand - 3,500 lbs. Accessories and Parts reviews from real customers.
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  • Reviews (50)
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Demco Accessories and Parts - 18787

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

Passenger's-side hydraulic trailer brake assembly features a single-plunger design. Galvanized steel resists rust, making the assembly great for boat trailers. Mounting flange has 4-bolt pattern.


Features:

  • 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
  • Single-plunger design delivers 15 - 20 percent braking in reverse
  • Riveted brake shoes provide increased durability
  • Periodic manual adjustment required
  • Mounting bolts sold separately
  • Made in the USA


Specs:

  • Configuration: right hand (passenger's side)
  • Dimensions: 10" diameter x 2-1/4" thick
  • Mounting flange bolt pattern: 4 on 4"
  • Wheel size: 13" - 15"
  • Axle rating: up to 3,500 lbs
  • 1-Year warranty


SB18787M Demco Galvanized 10" Marine Trailer Brake Assembly - Single Servo - Right Hand





Customer Satisfaction Score:

Ratings & Reviews

4.8

50 reviews
Review sort icon
Passenger's-side hydraulic trailer brake assembly features a single-plunger design. Galvanized steel resists rust, making the assembly great for boat trailers. Mounting flange has 4-bolt pattern.

by:

Everything as expected.



by:

Perfect fit. Just with it came with nuts and bolts.



by:

Quick and easy assembly with all the information needed



by:

Great products with great prices.



by:

Easy to mount and just like old one. Very fast delivery.



by:

As advertised, no problem to swap the old with the new.



by:

Very simple to install. Unbolted old and installed new and adjusted. So easy even a caveman could do it.



by:

Great products at great prices!



by:

Nice quality product. Easy to install... Well, as easy as any brake job could be. Spend a little bit and buy new bolts when you do this job.



by:

Bolted on and works fine. Reason for lowered rating is these are NOT MADE IN USA as stated on the website. I could have bought made in china parts cheaper on the jungle website but I paid more because USA quality matters to me. Need to change description.

Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

2/17/2025

Hey Andrew. I do apologize in regard to the miss information that we have. I went out to the warehouse to check these breaks and confirm that we got some incorrect information. I am getting this corrected so that our information is correct going forward. If you need anything, please don't hesitate to reach out to me.



by:

Easy to install and fast shipping



by:

Great products. Expert helpful videos for adjustment and installation. OEM parts and cross referencing made easy. Will buy products again on next axle rebuild.



by:

I have great service with Etrailer. Ordered the wrong part,called and was completely taken care of. Easy to do business with.



by:

Parts arrived exactly as described and worked perfectly. Great price, shipping was fast considering how far it had to come and arrived when it said it would. I've already ordered more parts from here and will continue to in the future.



by:

I’ve purchased items from etrailer over the years and they have never failed me getting the correct parts and on time. Thank you!



by:

Good product should coat all with non corosive coating and provide pre drilled wash out ports. Cad or Zinc plated bolts would be good as have to track down at an auto parts store and wern t plated.



by:

The product was first quality. It was packaged very well. Easy to install and yes, I wished I had ordered new bolts and nuts. Mine were a little bit rusty being on a boat. The only differences I noticed were that my old wheel cylinder was made of aluminum and this one was made of steel. Steel will rust but it will probably last longer.



by:

After going to numerous trailer stores and auto part stores in my home town I called Bill at etrailer. I found Bill to be very professional and helpful.. The package was ordered on Monday afternoon and was on my door step on Wednesday afternoon. The item was exactly what I had ordered. I will continue to purchase my trailer needs from Bill.



by:

Wheel came off boat trailer, must have bent backing plate. New huds rubbed and would not turn. Got new plates from etrailer fit perfect. Got here fast and easy to install.



by:

Good price and bolted up perfect! Etrailer.com has great prices and fast shipping when you need your parts fast. This is the 3rd complete trailer rebuild and I wouldn't think about buying from any other supplier.

Bobby M. Maryland



by:

So happy i found etrailer. They had the quality parts i had been looking for at a great price. I am equally happy with the speedy free shipping. I recieved the brake assemblies and installed them in less time than it took to locate them. Thank you. You will be my go to trailer parts supplier for all future parts. I have 5 different trailers and am sure i will require your services.
Robert K.



by:

These worked great. Much easier to replace the whole assembly like this, than replacing all of the original rusted out components. These are galvanized, so they should last a long time. I'm using these for a boat trailer for a 21 foot fiberglass euro styled V8 powered pleasure boat that weighs about 3000 pounds.



by:

When I realized my brakes were in need of repair and no local shop worked on trailer brakes I decided to do it myself.
With the help of the etrailer folks I had a new set of brakes and was ready for another fishing season.
Great products, they do what they say and great customer support.



by:

It all is working as planned thanks to Joanne



by:

Put new brakes,drums, bearings and seals and hubs on boat trailer found all parts here and received really fast always order parts for trailers here and always will


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See what our Experts say about this Demco Accessories and Parts

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    With surge brakes, you have a brake actuator applying the needed pressure to the brakes but to be able to back up you will need to have a manual lockout or an electric lockout solenoid, like # T4748800, which will close when you shift the vehicle into reverse, allowing the trailer to be backed up. You may also need a solenoid cover like the Titan # T4835800183, depending on what brake actuator you currently have. Typically surge brakes are found on boat trailers, and commonly the trailer...
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  • Solution to Allow Trailer with Surge Brakes to Back Up
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  • How To Activate Surge Brakes on Triple Axle To Verify Brakes Are All Working Properly
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  • What Causes a Trailer With Surge Brakes To Lockup While In Reverse
    The issue your friend is having with his trailer is a mechanical one so we can rule the vehicle out. The reasoning for this is because the only way you would have been able to back up the trailer with using just a 4-way trailer connector is if you either physically applied a manual lockout or the trailer had free backing braking assemblies. Surely you would know whether or not the manual lockout was used or not so that leads me to think you have free backing braking assemblies. The free...
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    Surge brakes will activate when backing the trailer up unless you do one of two things to address the problem. You can install free-backing brake assemblies on the trailer (I attached a link to a page that has all of the ones we carry) or you can use a reverse lockout solenoid which will prevent hydraulic pressure from making it to the wheel cylinders when the reverse light circuit activates the solenoid. If you have a Titan actuator you would need the part # T4748800 or if you have...
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  • Troubleshooting Surge Brake Actuator that Won't Release Brakes
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  • Trailer Surge Coupler Can be Pushed in By Hand and Brakes are Weak
    The coupler should be very difficult to push in by hand but it doesn't return on its own. There is likely a problem inside your coupler that will need to be addressed to get it working properly again. It is most likely the shock that is inside. There are replacement shocks but I would need to know the manufacturer and model of the coupler you have. I have included a link to the shocks we carry. If you can't find a part number or manufacturer on the coupler then you may be able to find...
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  • How To Check if Trailer Surge Brakes Are Working Properly On Tandem Axle Boat Trailer
    Checking the brakes can be done in two ways. The easiest way is to raise one side of the trailer and spin the wheels while someone applies the surge brakes at the coupler. The better way would be to remove each of the wheels and brake drums and activate the brakes while making sure the wheel cylinders and brake assemblies are functioning properly. After this the first thing I would do is bleed the brakes using the trailers surge coupler to force the fluid from the brake lines and make...
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    Image 1 for
  • Troubleshooting Trailer Surge Brakes That Activate in Reverse with New Truck
    A surge coupler/actuator will activate the brakes on the trailer unless it has a lockout feature, either a manual lockout as with coupler # T63FR or an electric lockout as on part # T4854020. Since the same trailer backs up without any problem using your other truck, the 2012 F-150, most likely that truck has a reverse light circuit present on the trailer wiring to deliver a lockout signal for the coupler's solenoid. If your new truck has only a 4-pole wiring setup then you'll just need...
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  • Troubleshooting Surge Trailer Brakes that Make Hammering Sound When Applied
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    Unless the trailer became completely unattached from your tow vehicle causing the breakaway pin to be pulled out, forgetting to lock the coupler to the hitch ball, while certainly something you want to double check the next time you tow, would not have caused the trailer brakes to engage during travel. The brakes locking up when going forward was likely caused by some kind of short in the trailer wiring. I recommend inspecting the brake output wire on the trailer for any exposed portions...
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    It sounds like the problem is in the wiring of your reverse lockout solenoid. Most likely the circuit is shorting out somewhere and is causing the circuit to over-draw which is why the fuse is popping and the wire is getting hot. I would inspect the wiring of the circuit and see if you can find any obvious signs of a short and fix as necessary. Cut or exposed wiring or corrosion can cause shorts. I attached an FAQ on trailer wiring for you to check out also.
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  • Troubleshooting 2012 Glastron Boat Trailer With Catching/Slipping Brakes When Moving After Stop
    With your boat trailer, you will have a brake actuating surge coupler. This means that when you brake the hitch ball will pressurize the plunger of your master cylinder applying hydraulic pressure to your brakes. Once stopped the internal shock like # T1242600 should release that pressure and it should allow pulling again without a catch. Since you are feeling a slip or catch, it is likely that shock is not returning correctly to the pulling position. This is likely the issue if there...
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  • Tie Down 70LP Actuator Is Locking Up Brakes After Backing Up
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    Image 1 for Image 2 for
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