What Activates Hydraulic Disc Brakes in a 5th Wheel Trailer?
Updated 02/17/2026 | Published 06/14/2024
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Question:
How do the hydraulic disc brakes work on a 5th wheel? What activates them? Is that component included in the 4 wheel package on the 12” brakes?
asked by: Ron K
Expert Reply:
That is a good question Ron. Disc brakes on a 5th wheel will require electric over hydraulic actuator like part # HS381-8067 to activate the disc brakes. It is not included with the DeeMaxx disc brakes part # DE28YR. The EOH actuator is going to provide the 1600 PSI that is needed to activate the disc brakes. If you tried to install the disc brakes straight to the current braking master cylinder in the fifth wheel then there would not be enough pressure to activate the brakes.
You will also need a breakaway kit like part # 20400, an electric brake controller part # 90195 and a flexi brake line kit like part # HS496-252 to switch over to disc brakes.
If you had a trailer with a trailer tongue and coupler you could use a hydraulic actuator but since you have a fifth wheel, you will need to convert over to electric over hydraulic to use disc brakes. I have added a helpful article that explains all of the parts that you need.
Product Page this Question was Asked From
DeeMaxx Disc Brake Kit - 12" Hub/Rotor - 6 on 5-1/2 - Maxx Coating - 6,000 lbs
- Trailer Brakes
- Disc Brakes
- Marine Grade
- 6 on 5-1/2 Inch
- Hub and Rotor
- 1/2 Inch Studs
- 6000 lbs Axle
- 15 Inch Wheel
- 16 Inch Wheel
- 16-1/2 Inch Wheel
- 17 Inch Wheel
- 17-1/2 Inch Wheel
- DeeMaxx
more information >
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Heather A.
2/17/2026
Hey Ron, how did things go switching your 5th wheel over to the electric over hydraulic setup for the DeeMaxx disc brakes? Your results could really help others thinking about the same upgrade.