1. Brake Actuator
  2. Demco
  3. Surge Brake Actuator
  4. Disc Brakes
  5. 2 Inch Ball Coupler
  6. 6000 lbs GTW
Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc - Zinc - 2" Ball - 6,000 lbs

Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc - Zinc - 2" Ball - 6,000 lbs

Item # DM8605101
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Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc - Zinc - 2" Ball - 6,000 lbs Disc Brakes DM8605101
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Surge actuator has a corrosion-resistant composite master cylinder and zinc plating, making it perfect for marine use. Leverlock coupler latch is easy to use. Electric lockout activates automatically to keep brakes from actuating when in reverse. Call 800-298-8924 to order Demco brake actuator part number DM8605101 or order online at etrailer.com. Free expert support on all Demco products. Guaranteed Lowest Price and Fastest Shipping for Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc - Zinc - 2" Ball - 6,000 lbs. Brake Actuator reviews from real customers.
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  • Reviews (20)
  • Q & A (47)
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Demco Brake Actuator - DM8605101

  • Surge Brake Actuator
  • Disc Brakes
  • 2 Inch Ball Coupler
  • 6000 lbs GTW
  • Demco
  • Bolt-On
  • Electric Lockout
  • Straight Tongue Coupler

Surge actuator has a corrosion-resistant composite master cylinder and zinc plating, making it perfect for marine use. Leverlock coupler latch is easy to use. Electric lockout activates automatically to keep brakes from actuating when in reverse.


  • Hydraulic actuator activates trailer's brakes when tow vehicle slows or stops
  • Electric reverse lockout lets you back up without actuating trailer brakes
    • Solenoid activates automatically when you shift into reverse
  • Leverlock coupler mechanism for simple, secure hookup and disconnect
    • Trigger-style latch is easy to use
  • Zinc plating offers excellent corrosion resistance
    • 500-Hour salt spray rating - great for marine applications
  • Composite master cylinder is durable and efficient
    • Glass-reinforced nylon construction resists rust and corrosion
    • Large reservoir provides increased capacity for brake fluid
    • Automotive-style diaphragm cap creates completely enclosed system to help prevent contamination of fluid
  • Large rear rollers allow for easy movement and smooth operation
  • Breakaway included
    • Snap hook on safety cable ensures secure connection to breakaway lever
  • Heavy-duty steel construction with sturdy, reinforced outer casing
  • Bolt-on installation
    • Requires 1/2" x 4-1/2" Grade-5 bolts (not included) for mounting
  • Made in the USA


  • Application: trailers with hydraulic disc brakes
  • Ball size: 2"
  • Gross towing weight: 6,000 lbs
  • Maximum tongue weight: 600 lbs
  • Mounting: straight, 3" wide trailer tongue
    • Bolt holes are 3" apart on center
  • Model number: DA66B
  • 1-Year warranty

When you apply the brakes in your tow vehicle, deceleration occurs and momentum pushes your trailer toward the rear of your vehicle. With surge brake systems, the hydraulic actuator is triggered as your trailer moves forward, once your tow vehicle starts to slow down. When this happens, the actuator contracts, applying force to its master cylinder. This in turn supplies the necessary hydraulic pressure to engage your trailer's brakes.

Electric Reverse Lockout

The electric reverse lockout on this trailer brake actuator is automatically activated when you shift your tow vehicle into reverse. The solenoid wires into your trailer connector - which connects to your tow vehicle - so that it can detect when you are in reverse. When your vehicle is in reverse, the solenoid ensures that the hydraulic actuator does not activate your trailer's brakes, thus allowing you to back up your rig. To use the lockout feature, you must have a 5-pole flat, 6-way round, or 7-pole trailer connector.

Sturdy, Corrosion-Resistant Construction

Made of sturdy steel, this hydraulic trailer brake actuator features a durable zinc coating that is designed to limit rust and corrosion. This zinc coat has a 500-hour salt spray rating, making the actuator perfect for marine use. In addition, the composite master cylinder is made of corrosion-resistant glass-reinforced nylon to further ensure durability for marine applications.

8605101 Demco DA66B Hydraulic Trailer Brake Actuator for Disc Brakes - Electric Lock-Out - 2" Ball Coupler - 6,000 lbs

Installation Details DM8605101 Installation instructions

Customer Reviews

Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc - Zinc - 2" Ball - 6,000 lbs - DM8605101

Average Customer Rating:  4.9 out of 5 stars   (20 Customer Reviews)

Surge actuator has a corrosion-resistant composite master cylinder and zinc plating, making it perfect for marine use. Leverlock coupler latch is easy to use. Electric lockout activates automatically to keep brakes from actuating when in reverse.

- DM8605101

Delivered as advertised. Installed with no trouble. After installing and connecting brake line, it is necessary to bleed the system by pumping the coupler/brake master cylinder in and out, while someone else opens and closes the bleed valves on each brake. It is very advisable to disconnect the shock absorber for this purpose, as the job of pumping the coupler in and out is hard enough without it. We used a 5' 2x6 for that purpose, anchoring the bottom end with the safety chains. Instructions for doing this would have been helpful, but none were enclosed. Also, the unit, though well made and well plated, came without the 2 high grade 1/2" bolts and locknuts needed. We feel the bolts ought to be included. Service and follow-up by E-Trailer is excellent. We have not yet towed the trailer with the unit installed. 131543

- DM8605101

Arrived quick (Way faster than I expected). Haven't installed yet but part is what was advertised 923821

- DM8605101

Looks like a good product although I haven't been able to bleed the brakes yet. 867820

- DM8605101

Ordering and shipping was excellent! The only reason I didn’t give 5 stars is the product itself. I knew this while purchasing but I do not like that you have to drill a hole in the top of your tong tube to route the brake line. It is not an easy bend to make with a metal brake line and it is not covered by the cover provided so I had to fab up some angle to protect it from being stepped on. 858156

- DM8605101

I was tempted to replace the parts in my old unit but figured it was more cost effective to buy a new one. The unit bolted on perfectly and has been working flawlessly since it was installed. 803747

- DM8605101

As usual, great product, good price, super fast ship. AAAAAAAAAAAAAAAAA++++++++++++++++++ 774280

- DM8605101

Product arrived well-packed. I have yet to install it since I am still waiting for the remaining parts to replace my brake system. I have one question though. Does it matter which wire of the solenoid go to the reverse light? They are both yellow on my unit, so I am not sure which one is which. 733421

- DM8605101

Replaced my old one with the new actuator and cannot believe how smooth it operates. No more banging or movement when I stop or go. Great product. 706119

- DM8605101

fit the job 703892

- DM8605101

Product arrived on time & was an exact replacement for the old one. I'm very happy! 668889

Still working great!
JOHN B - 07/12/2020


- DM8605101

Appears well made and designed. Like plastic master cylinder body. Iron master cylinder on unit I am replacing was hopelessly corroded to point where I couldn't get cap off reservoir. 668536

- DM8605101

Nice product and great price! Arrived on time!! 653402

- DM8605101

Exactly what I needed plus the best price. Shipping was free and very quick. Etrailer is always my go to for parts 616294

- DM8605101

purchased Kodiak brakes and trailer coupler Excellent data on website plus the part arrived as expected. Price was competitive when you consider the freight cost When purchasing the actuator/tow assy dont forget that the brake line is too short and will require a 90 degree elbow with flare plus a small length of hose with flare FYI 615106

- DM8605101

I could not be happier, What a diiference to have not just good brakes, but great brakes. Plus, the install was so easy, all the hardware was a perfect fit, instructions were right on the money (btw, I'm a retired engineer from a nuclear plant and I wrote procedures, so I'm picky) Anyway, towed the boat 1,000 miles and what a reassuring feeling to know that the equipment is in good working order and does the job when called upon. I'm attaching a couple of pictures so you can see what I did. Thanks again, I will be using etrailer in the future anytime I need something, feel free to pass on my comments 614785

- DM8605101

I recently purchased a used boat and trailer. Trailer had a surge brake hitch that had not been maintained and had been discontinued. I replaced that non-operational unit with this one. Installation was easy, my only other expense was the need to replace the two attachment bolts with longer ones. I also replaced the fiber nuts and washers. This unit has a much better ball lock up mechanism than my old hitch. A great new hitch at a great price, thank you etrailer. 595162

- DM8605101

Dear eTrailer, I purchased an electric over hydraulic disc brake kit from you last year. It greatly increased the stopping distance and therefor the safety for my family. I recently purchased a used four winns boat with trailer. The trailer has a surge hitch and disc brakes. The surge hitch was clogged and inoperative. It has also been discontinued. I will be replacing it with this new unit and expect to have working trailer brakes. Thank you for your great products and wonderful prices. 593034

- DM8605101

Great product. It fits like a glove. All parts and component seem to be high quality. It was a little longer than expected but still a solid piece. Super fast delivery at no cost it is hard to beat. 591702

- DM8605101

Good price , quality and fast delivery , will buy things from etrailer again 590971

- DM8605101

I just finished the install and went well . Its was a fast install and when i call to order all the staff were very helpful 193485


Ask the Experts about this Demco Brake Actuator

  • Availability of Replacement Master Cylinder for Atwood 85778 Actuator
    The Atwood master cylinder 85841 is no longer available. Atwood doesn't product any actuator components anymore so it's getting harder and harder to track down replacement parts. We do not have any other replacement units that would be compatible with your Atwood actuator so your best option at this point is really to replace the entire actuator assembly. This will also ensure that replacement parts will be readily available if needed down the line. To replace the Atwood 85778 model...
    view full answer...
  • Replacement Disc Brake Surge Coupler for 2004 Nitro Boat Trailer
    We can help you with a new surge brake coupler for your straight-tongue boat trailer. Your photo shows a label indicating the old coupler is designed for disc brakes which will use a coupler with higher pressure than a coupler for drum brakes. For a 6K disc brae coupler you can use Demco part # DM8605101 which includes an electric lockout feature. It fits a 3-inch wide channel tongue and uses 1/2 x 4-1/2 Grade-5 bolts for mounting.
    view full answer...
  • Trailer Surge Brake Actuator to Replace Atwood 85778
    Atwood doen't manufacture trailer surge brake actuators anymore, but we do have a good replacement for you. I'd recommend the Demco # 8605001 for drum brakes or # DM8605101 for disc brakes. The actuating couplers are rated for up to 6000 GTW, are compatible with a 2 inch trailer ball and will fit your 3 inch wide channel tongue. Neither actuator has an electric lockout, it's not really necessary on the drum brake model since drum brakes don't work well in reverse, but if you use the...
    view full answer...
  • Atwood 82453 Surge Brake Coupler Master Cylinder Replacement
    There is no longer a replacement for that particular master cylinder. Atwood is out of business and Demco did acquire the coupler part of their business, but have not made replacement parts for older couplers. The closest option we have to replace your Atwood 82543 actuator is part # 8605001. However, it doesn't have the lockout like your Atwood does. To add a lockout and shield use # DM5836. It wires into the reverse light circuit on your trailer through the trailer connector. I...
    view full answer...
  • How Much Brake Fluid Should Surge Brake Actuator Have
    A surge brake actuator such as the Demco Hydraulic Trailer Brake Actuator - Drum Brakes # 8605001 or Disc Brakes # DM8605101 should have the fluid level topped off. You can see this in the linked video install that I added for you to check out. I have also added a link to our entire selection of hydraulic surge brake actuators if you are in need of a new one. You can filter them by either drum brake or disc brake applications, as well as capacity and hitch ball size to make your selection...
    view full answer...
  • Disc Brake Master Cylinder and Bypass Lockout Solenoid for Demco Surge Brake Actuating Coupler
    You gave quite a few options, but the Demco Solenoid Kit - Factory Installed - Disc Brakes # DM5752 sill be the best option as you stated. You can reuse your other parts as you stated. This assembly will have the spring and piston as you stated. If you need help with the axle, I recommend the Kodiak Disc Brake Kit - 12" Hub/Rotor - 6 on 5-1/2 - Dacromet - 5,200 lbs to 6,000 lbs # K2HR526D and Kodiak Hydraulic Brake Line Kit - Single Axle - 18' # 18SI-BLKIT.
    view full answer...
  • Can Coupler Portion Be Replaced On 2007 Wesco Dual Axle Boat Trailer with Surge Brake Actuator
    The best option for a surge brake actuator with a bad coupler is to replace the entire actuator. I would need to know the exact make and model of your surge brake actuator in order to see if a replacement coupler is available which is not always the case. I don't have any info on your trailer in particular but the Demco Hydraulic Brake Actuator part # DM8605101 for disc or part # 8605001 for drum are both great options so long as the frame, coupler, and weight rating are all correct. I...
    view full answer...
  • Instructions to Bleed Demco Hydraulic Brake Actuator for Disc Brakes
    You will need to follow the instructions set by Demco in order to bleed the 6,000 lb Demco Hydraulic Brake Actuator # DM8605101. I have added a cut out from the linked installation instructions which provides the steps you will need to take, and you can also refer to those instructions. I have also added a link to a video review of the Demco Hydraulic Brake Actuator # DM8605101.
    view full answer...
  • Recommended Replacement Actuator for Atwood 85778
    When it comes to options available to replace your Atwood 85778 Surge Actuator, I recommend using the Titan Zinc-Plated Brake Actuator w/ Electric Lockout - Disc - Multi-Fit Ball - Bolt On - 6,000 lbs # T4745720, which has all the same features as the Demco # DM8605101 but at a little better price point. This actuator is designed for working with disc brakes and will work with trailers up to 6000-lbs. The only other option available for disc brakes is the Titan Zinc-Plated Brake Actuator...
    view full answer...
  • How to Wire Reverse Lock Out Solenoid on Hydraulic Trailer Brake Actuating Coupler
    I don't have a wiring diagram, but I'd be happy to explain it for you. In order for the reverse solenoid on a Hydraulic Brake Coupler like # DM8605101 to function, one of the two wires leading from it needs to be connected to the wire from the center pin of the trailer connector, which is typically the yellow or purple wire (use a circuit tester like # 40376 to confirm). The remaining wire is grounded to the trailer frame. On the vehicle side, you'll need to make sure that the...
    view full answer...
  • Replacement Surge Brake Actuator Recommendations for Atwood 82541
    I recommend either using the Demco 6K # DM8605101 if you want a standard actuator that fits a 2" hitch ball or the Titan 6K # T4745720 if you like the option of the coupler fitting with either a 1-7/8", 2", or 50 mm hitch ball. Both options have the same weight rating, fit on a 3" wide channel tongue, and have mounting bolts holes with 3" on center distances between them. I'm not exactly sure what the mounting bolt hole locations were for your Atwood 82541 actuator so if the bolt hole locations...
    view full answer...
  • Picking Out Brakes for 2003 Mastercraft Maristar 210 Boat Trailer
    I am sure we have a suitable replacement surge actuator for your trailer. But when I tried to look up your trailer on google every one of the pictures had the coupler cut off. If you could send me a picture of your coupler as well as the weight of your trailer when loaded I can give you our best recommendation. Do you need brake assemblies as well? That's the part that fits behind the hub/drum.
    view full answer...
  • What Hardware Is Needed for Installing Demco Hydraulic Brake Actuator # DM8605101
    The correct hardware to use to install the Demco surge actuator part # DM8605101 is 1/2" x 4-1/2" Grade-5 bolts which we don't offer. This would be super easy to track down at a local hardware store though.
    view full answer...
  • Solution for Converting Trailer with Atwood Drum Brake Surge Actuator to Disc
    Some people have had luck punching out or removing the check valve in their drum brake actuator master cylinders to allow them to be used with the higher PSI requirements of disc brakes but the manufacturers of the actuators will not endorse this so we can't either. If Atwood replacement parts were still available the easiest solution would be to replace the master cylinder with the correct disc brake master cylinder. Since that's not possible the best solution would be an all new actuator...
    view full answer...
  • Can a Surge Brake Actuator for Drum Brakes Be Compatible with Disc Brakes?
    Most brake actuators for drum brakes like your Dico 6000 lb cannot be used for disc brakes. This isn't based on weight capacity, but rather based on the pressure the master cylinder can handle. Most drum brake systems give you 1000 to 1200 psi, and disc brake systems require more with most rated at 1600 psi. The actuators are specific for disc or drum because drum brakes with a disc brake actuator would give too much pressure and in your case, the drum brake actuator will not give enough...
    view full answer...
  • Solutions for Trailer that Has Atwood Actuators Mounted Between Frame Rails
    Your trailer currently has an Atwood actuator (no longer made) welded between the two frame channels from the outsides. If you were able to remove the actuator you could replace it with the Demco part # DM8605101 that you referenced. You'd weld it in place just like it is currently. Or you could convert the trailer to electric over hydraulic using an actuator like the part # HBA16 for if you have disc brakes or # HBA-10 for if you have drum brakes.
    view full answer...
  • Recommended Disc Brake Components For Demco Kar Kaddy Tow Dolly
    For your Demco Kar Kaddy, the Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc - Zinc - 2" Ball - 6,000 lbs # DM8605101 will work great. The Kodiak Disc Brake Kit - 10" Rotor - 5 on 4-1/2 - Dacromet - 3,500 lbs # K2R35D will not work well with the brake flange so you will want to upgrade the flange to the # 4-35 since the Kar Kaddy has a unique flange instead of the standard. The idler hubs # DM04369 will work well without any modifications. Then you will just need brake lines...
    view full answer...
  • Troubleshooting Trailer Surge Actuator that Slides All the Way In Without Much Braking Power
    Sounds like you have some air bubbles in the brake lines of your trailer and the system needs to be bled and topped off. Or you have a leak and would need to track and down and repair it. We happen to have a video on the proper procedure for bleeding trailer brakes. I have attached the video below as well as outline the method here for you. First top off the master cylinder with appropriate fluid. Next you will want to pump the fluid from the master cylinder. You can do this by unbolting...
    view full answer...
  • Replacement Disc Brakes And Actuator For 2005 Trailmaster Single Axle Boat Trailer
    It sounds like you already have brakes on your trailer. If so, there may not be a need to replace the brake lines and you could install a brake kit like part # K2HR35D. This is designed for 3,500-lb axles and includes hub-and-rotor assemblies; calipers; and mounting brackets. The hub and rotor have a 5 on 4-1/2 wheel bolt pattern. You would then need the actuator. I recommend part # DM8605101. This is the Demco hydraulic brake actuator with electric lockout. This has a 2 inch ball coupler...
    view full answer...
  • Is There any Adjustability with Trailer Surge Brakes
    Surge brakes do not have any adjustability. If you want to use them on steep hills your solutions would be best. Or you can look into an electric over hydraulic setup which will allow you to use a brake controller to activate the brakes. This gives you total flexibility and control. I attached a help article to this page that would walk you through the entire process of adding EOH brakes to a trailer like yours.
    view full answer...
  • Will 6,000 lb Surge Brake Actuator Work on Single Axle Boat Trailer
    The Demco Hydraulic Brake Actuator # DM8605101 will work great for you; the 6,000 lb tow rating and 600 lb tongue weight rating are just the maximum capacities for the actuator and you won't have an issue with your single-axle boat trailer being under that weight rating. This actuator is designed for use with trailers that have disc brakes and it will fit a 2 inch hitch ball. I have added a link to a video review of the actuator for you to check out as well.
    view full answer...
  • Disc Surge Brake Actuator for Eagle 25 Trailer
    Since you said the trailer has a weight of around 4,000 lbs and has disc brakes the surge actuator you'd want is the Demco part # DM8605101 which is for disc brakes and has a 6,000 lb capacity plus has a reverse lock out to allow the trailer to back up without activating the brakes.
    view full answer...
  • Replacement for the Reliable ACT-6K Brake Actuator
    From my research, the Reliable ACT-6K Brake Actuator was rated at 6,000 lbs, for disc brakes, and a 2" hitch ball. If this is correct then I recommend using the Demco Hydraulic Brake Actuator part # DM8605101 which has both a master cylinder and electric lockout feature like you mentioned. The Demco actuator is an excellent option for you. It has a zinc plated finish for maximum corrosion resistance and it is made right here in the U.S.A. with a one year warranty. I have attached a...
    view full answer...
  • What is the Correct Amount of Brake Fluid for the Demco Disc Brake Actuator # 8605101
    According to Demco, you will want to fill the brake fluid reservoir 3/4 of the way full with new DOT 3 or DOT 4 brake fluid. If you are bleeding the brakes, you will want to check the brake fluid level to ensure that it remains above half full during the bleeding process. Once you have finished bleeding the brakes, you can fill it to 3/4 full.
    view full answer...
  • Replacement Titan Model 60 Actuator for Disc Brakes
    We have exactly what you are looking for. The disc brake version of your current Titan Model 60 is part # DM8605101. This actuator fits a 3 inch wide channel, and has a maximum weight capacity of 6,000 lbs. The coupler is compatible with 1-7/8, 2 inch of 50mm trailer balls. This actuator will supply the higher psi needed to actuate your new disc brakes properly.
    view full answer...
  • Recommended Replacement for Atwood Surge Brake Actuator 85778
    The manual lockout on your Atwood 85778 surge brake coupler is there so that you can back up the trailer without the brakes locking up on you. Yes you can safely tow your trailer with the broken manual lockout, you just have to make sure you don't put yourself in the situation where you have to back your trailer up. Since Atwood went out of business there aren't any exact replacements for your coupler but you can use a different brand. The only thing I was able to find online about the...
    view full answer...
  • Master Cylinder for Fulton A-60 for Conversion to Disc Brakes
    We do have one of the parts you are looking for with the master cylinder for your A-60, which is the Replacement Master Cylinder Assembly # DX44FR. Having said that, there is no hardware inside the tongue or solenoid we know will work with this coupler. You may be better off removing that altogether and replacing it with the Fulton Fold-Away Coupler Hinge Kit for 3" x 3" Trailer Tongue # FHDPW330300 and Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc # DM8605101. In regards...
    view full answer...

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Info for this part was:

Edited by:
Leah B
Expert Research:
Mike L
Expert Research:
Jameson C
Written by:
Lindsey S
Updated by:
Laura H
Updated by:
Hannah L
Installed by:
Randy B
Video Edited:
Zach D

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