Replacement Hydraulic Cylinder Assembly for Demco 10" Marine Free Backing Brakes - Left Side

Part Number: DMSB9777M

$40.07

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demco accessories and parts trailer brakes uni-servo

demco accessories and parts trailer brakes hydraulic drum replacement cylinder assembly for 10 inch marine free backing - left side

demco accessories and parts wheel cylinder uni-servo dmsb9777m

demco accessories and parts trailer brakes wheel cylinder replacement hydraulic assembly for 10 inch marine free backing - left side

demco accessories and parts trailer brakes wheel cylinder dmsb9777m

demco accessories and parts trailer brakes uni-servo replacement hydraulic cylinder assembly for 10 inch marine free backing - left side

demco accessories and parts hydraulic drum brakes uni-servo dmsb9777m

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Demco Trailer Brakes DMSB9777M Review

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Replace the left side hydraulic wheel cylinder assembly for your Demco 10" marine-grade hydraulic free-backing brakes (40716). 1-800-940-8924 to order Demco accessories and parts part number DMSB9777M or order online at etrailer.com. Free expert support on all Demco products. Great prices and Fastest Shipping for Replacement Hydraulic Cylinder Assembly for Demco 10" Marine Free Backing Brakes - Left Side. Accessories and Parts reviews from real customers.

Demco Accessories and Parts - DMSB9777M

Replace the left side hydraulic wheel cylinder assembly for your Demco 10" marine-grade hydraulic free-backing brakes (40716).

Features:

Replace the hydraulic wheel cylinder assembly for your left side Demco 10" marine-grade hydraulic free-backing brakes (40716)
Includes hydraulic cylinder with plunger
Made in the USA

SB9777M Replacement Wheel Cylinder Assembly for Demco 10" Marine Free Backing Brakes - Left Side

Video of Replacement Hydraulic Cylinder Assembly for Demco 10" Marine Free Backing Brakes - Left Side

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

Video Demo Demco Accessories and Parts DMSB9777M

Demco Trailer Brakes DMSB9777M Review

Video Transcript for Demco Trailer Brakes DMSB9777M Review

Speaker 1: Today we're gonna take a look at the replacement left side hydraulic wheel cylinder assembly for the Demco 10-inch marine free backing brakes. This part will replace the hydraulic wheel cylinder assembly on your left side of your Demco 10-inch marine grade free backing brakes, part number 40716. We do sell that assembly separately on our website. This will include the hydraulic cylinder with the plunger. It is a uni Servo, so it is the single plunger design, and this is designed to fit on the left hand driver's side. If you'll notice, the cylinder itself has a nice zinc plating to it to help resist corrosion.

But that should do it for the review on the replacement left side hydraulic wheel cylinder assembly for the Demco 10-inch marine free backing brakes.

Customer Satisfaction Score:

96% were satisfied with this product

4% of customers were not satisfied

Product did not meet expectations
Wrong item was ordered
Alternate product found

4% of customers were not satisfied

Product did not meet expectations
Wrong item was ordered
Alternate product found

4.8

34 reviews

5 Stars		(30)
4 Stars		(3)
3 Stars		(0)
2 Stars		(1)
1 Star		(0)

by: Randolph 10/17/2025

Certainly not as heavy and well made as the original wheel cylinder but I guess time will tell as to how they hold up.

by: Rick 08/09/2025 One Year Later

direct replacement, fast service

by: Garry 05/29/2020

I bought wheel cylinders for an older Demco Kar Kaddy SS. The parts were a perfect fit, work as they should, and I have no complaints with the parts. Did have an issue with their shipping department, but they did the right thing. All-in-all, I recommend etrailer.com.

by: Seth 08/20/2022 One Year Later

Had to rebuild my tow dolly and etrailer had the correct parts, fast shipping with unmatched quality. No need to go anywhere else. Thanks etrailer

by: Joseph 08/02/2020

Fit perfectly as required. Used on Ezyloader
10,000lbs tandem rear axle boat trailer. Relatively easy to find on website, reasonably priced, fast shipping. Excellent experience.
Thank you.

by: William 07/12/2022

Just what I needed to get my boat trailer brakes going safely again. Thank you

by: Nels 09/22/2022

The wheel cylinder I ordered arrived on time. Installed it. Works great. etrailer advised me my order was received, when it was sent and followed up with me. Great experience.

by: Walt V 05/25/2020 One Year Later

The exact replacement parts I needed, easy to install and good price. Has been working GREAT for the past year.

by: Bruce 06/03/2025 One Year Later

Seem great, still working!

by: Paul 02/22/2023

Great service! Excellent Service! Fast Shipping! Helpful in every way!

by: Norman T 01/02/2023

etrailer is the best place for trailer parts.

by: Serge 08/19/2024 One Year Later

J’ai eu un excellent service et la pièce était impeccable

by: Ed 06/25/2025

Perfect fit.

by: Peter 10/25/2017

Parts arrived when promised and have been installed.

Peter S. One Year Later

10/25/2018

They have been working fine.

by: Ronald 04/26/2025

Great product

by: Richard P 08/04/2023

same as previous review! Sorry for the brevity- I am so old school that I don't text, tap, e-mail or even use the camera or phone book on my old flip-phone! Thanks again for your pleasant service!

by: Ostene 09/29/2024 One Year Later

They're holding up and not leaking

by: Garry 02/23/2024 One Year Later

working great having no problems

by: Lawrence 08/12/2019

Bought both left and right sides they worked great

by: Leo 09/07/2018

Good service fast delivery.

by: Florin 12/04/2021

Thanks for a prompt delivery.
You guys rock.

by: Gilberto 12/15/2025

by: Mark 07/14/2023 One Year Later

by: Alexei 08/21/2026

by: Jeremiah 07/28/2023

true

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Replacement Parts for Brakes on Demco Kar Kaddy KK460SS
Hi Doug; it sounds like you have drum brakes on your KK460SS. For a full replacement we have the Demco Hydraulic Brake Kit # 40716-15. We also have the Replacement Brake Shoe Lining for Demco/Dico 10" Free-Backing Hydraulic Brakes # BP04-126 along with the Replacement Hydraulic Cylinder Assembly - Right # DMSB9776M and Left # DMSB9777M. It usually ends up being more cost effective to completely replace them when parts start to wear out.
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Replacement Drum Brake Wheel Cylinders for Demco KK460SS Kar Kaddy Tow Dolly
We can certainly help you with that. You'll need the Right Wheel Cylinder Assembly, part # DMSB9776M and the Left Wheel Cylinder Assembly, part # DMSB9777M
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Replacement Wheel Cylinders for Demco Kar Kaddy KK360SS
I contacted Demco as you list that you have a Demco Kar Kaddy Model KK360SB. Since there is not an SB model, I presume you are referring to the KK360SS. They informed me that the needed parts are, Right Wheel Cylinder Assembly, # DMSB9776M and the Left Wheel Cylinder Assembly is, # DMSB9777M. I am unable to identify for you the year your Kar Kaddy is.
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Replacement Master Cylinder and Wheel Cylinders for Demco Kar Kaddy 2
I reached out to my contact at Demco who said that the master cylinders for the older (80s) Kar Kaddy 2 either used a Demco actuator or a Dico actuator. If you have the Dico actuator then you need part # T4395100 for drum or part # T4820000 for disc brakes. If you have the Demco version let me know and I can point you in the right direction. For the wheel cylinders you need part # DMSB9777M for the left side and part # DMSB9776M for the right side.
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Info for this part was:

Installed by:

Jeff D

Written by:

Wilson B

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