RV Towed Car Braking – Roadmaster InvisiBrake Auxilliary Tow Brake System Installation

TheRVgeeks Great RV Products, Towing, Updates & Upgrades 7 Comments

Flat towing a car (4 wheels down) behind a motorhome requires the installation of an auxiliary braking system to manage the car’s weight, and to bring it to a stop in the unlikely event of a breakaway. Our old system has been giving us trouble for a while, so we had Roadmaster install a new InvisiBrake on our 2003 Honda CR-V at their factory in Vancouver, WA.

We’d been having problems with our original (17-year-old) braking system for several years, requiring troubleshooting, repair and adjustment on a more and more frequent basis. It was an old, no-longer-manufactured product electrically triggered by applying the brakes in the RV. It required a vacuum pump to keep the car’s brakes working, so that it wasn’t just pulling on a dead brake pedal. Because diesel RVs don’t generate vacuum a dedicated pump needed to be installed on the RV… and an air line had to be connected across the tow bar to supply the vacuum to the car’s braking system.

Because that system had become more and more problematic every year, we knew it was time to replace it. We looked at all of the options available… including systems that tap into the air brakes on the RV. We chose the Roadmaster InvisiBrake for several reasons:

  1. It’s truly invisible. With the main unit installed in the underfloor compartment in the rear of our CR-V, there aren’t any components that are visible inside the car.
  2. There’s nothing to take in/out of the car to get it set up for towing… everything is built in and ready to go.
  3. It doesn’t require any additional connections/cables across the tow bar (like our old system did). Braking signal comes through the existing electrical umbilical, so it simplifies connecting the car to the RV.
  4. It includes a built-in vacuum pump that maintains vacuum in the car’s braking system. This ensures that braking application is smoother and easier… and that the system isn’t acting on a “dead” brake pedal. There’s no more need for an auxiliary pump, plus it remains with the car (powered by the car’s battery) in the unlikely event of a breakaway, which is of course where it’s needed!
  5. The system actually supplies charging to the car’s battery while we’re towing, ensuring that the InvisiBrake and brake lights don’t deplete it during long days of driving. The extra power comes across the umbilical cable from the RV as an integral part of that cable.
  6. We like the fact that it doesn’t tap into the air brake system on the RV. There are several options out there that do that (including one from Roadmaster, called the BrakeMaster… more specs/details available here), but we’ve always been a bit nervous about adding anything that could impact the functioning of the RV’s brakes. Yes, we know that those systems are tested and designed to ensure they don’t compromise the brake system’s integrity. And, yes, we know that those systems are proportional (the same amount of brake pressure is applied to the car as you’re using on the RV) as opposed to progressive (the car’s brakes are slowly and steadily applied, with increasing pressure, the longer the braking signal is triggering them), like the InvisiBrake is. But we’re still happier NOT tapping into the RV’s air system. And we’ve had a progressive system on our CR-V for the past 17 years, and the functionality has been fine, until we started having repeated intermittent problems, unrelated to the progressive/proportional question.

We’ve had the InvisBrake in place and in use on our CR-V for the past 9 months, and we love it! Combined with our Nighthawk tow bar, we’re more confident than ever that our Honda will safely and securely follow us wherever we tow.


Roadmaster has agreed to offer our viewers an exclusive package when they buy a Nighthawk directly from the factory. To take advantage of this deal, call Roadmaster at (800) 669-9690 then select option 2 for Sales. When you order your Nighthawk, just tell them you’d like the “RVGEEKS PACKAGE” and they’ll include a free heavy-duty tow bar cover and a free hitch receiver lock. This $89 value will keep your beautiful new Nighthawk secure and protected, like we keep ours. And FREE SHIPPING is included, too!

(800) 669-9690 – then select option “2” for Sales


For more info on towing, be sure to watch Season 2, Episode 4 of The RVers, where I interviewed Roadmaster VP David Robinson. If you missed it on The Discovery Channel, Season 2 premieres on iTunes/Apple TV & Google on July 7, 2020, and Episode 1 is FREE to download THAT DAY ONLY!

The entirety of Season 1 is available for streaming on iTunes/Apple TV, Amazon Prime Video, Google Play and Microsoft Xbox as well as airing on PBS and Fun Roads TV stations around the USA. Check out TheRVers.tv for more details on how to watch in your area, or to order to order your own copy on DVD. All streaming, DVD and PBS versions of the show are commercial-free, and include bonus segments!

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Comments 7

  1. Hi Guys I just received my Knighthawk tow bar,,my question is when behind motor home and pulling away do i have to do anything special to lock in..not sure, please Help Thanks

    1. Post

      Hi Anthony! You’re gonna love your Nighthawk!! Roadmaster’s instructions say you don’t have to do anything other than to pull away slowly in the RV until both arms lock (which you should be able to see in the backup camera). We usually prefer to try and get the arms to lock by gently backing the car away from the RV before we drive away. But that’s just our preference, and not Roadmaster‘s recommendation. As long as you don’t take off like a bat out of hell in the RV and risk suddenly extending the arms, you should be fine.

  2. Two summers ago, I was at an FMCA convention and Roadmaster was offering trade-in upgrades to an Invisibrake, and I was tired of my Even Brake by then (getting on my knees next to the toad to put it on wasn’t fun, and I had even had two instances where it jumped off the pedal, latch and cotter pin notwithstanding). I bought it used at a good price and got three years out of it, but I had decided its time was up. So, I left the rally with an unplanned but very welcome upgrade: an Invisibrake installed by a Roadmaster factory tech, and the upgrade discount was more than what I paid for my old Even Brake, so it was a total win :-)

    After two years, I’m still totally happy with the Invisibrake, it’s a wonderful system and saves me several minutes each time I hook up my toad.

    1. Post

      Wow, JB! That was a great confluence of events! Glad to hear you’re enjoying the Invisibrake… we can only imagine it’s a lot easier then installing & removing the EvenBrake! Safe travels!

  3. Hi guys,
    Great video as usual. I have a few questions for you.

    I have been using Blue Ox with Air Force 1 breaking for around 50,000 miles without any issues towing my very heavy full size diesel pickup. However, we are now looking to buy and tow a Jeep Wrangler instead of the truck. I broke my airline once due to carelessness and am considering the Roadmaster with InvisiBrake as you said it does not need an airline but in your video it looks like you have an airline hooked up. Why? Without that airline all you should have is the electrical cord correct? Lastly, where would you consider installing the InvisiBrake in a soft top Jeep Wrangler, under the hood perhaps?

    Thanks again and keep those videos coming as I have been a fan for years.

    1. Post

      Hi Lenny. Thanks! Sorry if it wasn’t clear, but that air line was for the OLD system (and it wasn’t an airline connected to our RV’s braking system like your Air Force 1… but to an auxiliary vacuum pump that was installed separately on the RV), and ALL of it was removed, since it was no longer needed for the Invisibrake. Now, the only things to connect between the RV and car are the tow bar itself, the safety & breakaway cables, and the electrical umbilical. LOVE it! As far as placement of the InvisiBrake unit, you may want to double-check with Roadmaster directly, but we don’t think it’s intended to be installed outside at all… even under the hood. But you might be able to fit it under one of the front seats, under the back seat, or somewhere else (again, we’d bet Roadmaster may have some suggestions)!

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