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When you hit the brakes in your motorhome, you want your towed vehicle to respond in perfect sync. The Roadmaster BrakeMaster for RVs with Hydraulic Brakes measures the pressure from your RV’s hydraulic brakes and applies the same force to your towed car’s brakes at the same time. Because it’s a truly proportional system, the braking power is matched automatically—light for gradual stops and firm for quick ones. There’s no false activation from bumps or dips, just smooth and predictable braking every time.
Most of the BrakeMaster system installs permanently, so it stays out of sight and out of your way. When it’s time to tow, attach the lightweight actuating cylinder between the brake pedal and driver’s seat. It braces securely for precise braking, then disconnects quickly for storage. The cylinder is about 2' long and requires either a custom seat bracket or a universal floor plate (450650-01, sold separately). That design gives you the reliability of a fixed system with the flexibility of a quick setup.
Unexpected disconnections can happen, but the included BrakeAway system is ready if they do. The breakaway reservoir keeps a reserve of pressurized air that will immediately apply the towed car’s brakes if separation occurs, bringing it to a controlled stop. It meets U.S. and Canadian braking requirements, adding an extra layer of safety on every trip.
Not every system confirms when your towed car is actually braking, but this one does. The LED indicator light mounts on your RV dashboard and connects directly to the towed car’s brake light switch. When the light comes on, you know the pedal is being pressed and the brakes are engaged. It’s an easy way to monitor performance without guessing what’s happening behind you.
This hybrid design uses your RV’s air compressor and a proportioning valve to send just the right amount of air to the towed car’s braking cylinder. The result is responsive, balanced braking that stays consistent on flat roads or mountain descents. Once installed, it delivers the kind of steady, trouble-free performance you can depend on every time you tow.
Flat towing can be a much more convenient way to take your car RVing with you than using a trailer or a tow dolly. It'll save you storage space both at home and at the campsite, and it takes less time and hassle to hook up.
To flat tow your vehicle, there are 5 basic components you're going to need: a tow bar, a base plate kit, a safety cable set, tow bar wiring, and a flat tow braking system.
| For the RV | Between the RV and Towed Car | For the Towed Car |
|---|---|---|
| Hitch | Tow bar | Base plate |
| Wiring plug | Safety cables | Braking system |
| Wiring adapter cord | Wiring kit/diodes |
The custom-fit base plate installs on the frame of your toad so you can connect the car to your RV with a tow bar. Hook up safety cables between the vehicles to ensure that the toad does not separate from the motorhome if the tow bar becomes detached. Tow bar wiring syncs your vehicle's signal lights with your motorhome's tail lights, as required by law in most states. Finally, the flat tow braking system - also required in most states - activates the brakes in the toad when you hit the brakes in the RV, making for smoother, safer braking, and preventing wear on your motorhome.
Alternate Instructions
Customer Satisfaction Score:
78% were satisfied with this product
22% of customers were not satisfied
Ratings & Reviews
John
5/3/2026
Working well.
James D.
5/4/2026
Dave
2/6/2021
It’s now been a year and a number of both short and long trips since I installed the RoadMaster 9100 brake system. Works perfectly, is easy to quickly setup for towing and just as easy to remove for driving my toad. Satisfied buyer who continues to use etrailer products when there is a need.
Allan
10/30/2022
Many thousands of miles, across deserts and over mountains, without a single issue or problem! Definitely recommend this system to any RV’er with coach air brakes.
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Armand L.
8/13/2015
I installed on SENECA 2015 for towing JEEP WRANGLER 2012 ,and after one year I am very satisfy of this system.It is really a progressive braking system working smoothly and efficiency . PS : sorry for my english , I am a french speaker.