Community Forums

dwirch · 03-22-2021, 12:35 PM

Good morning/afternoon/evening!

The wife and I finished our first shakedown cruise with our new-to-us 2007 Horizon. Since it was just an overnighter, we didn't bother bringing another vehicle with us. For longer trips, we're planning on getting our 2017 Jeep Wrangler JKU (as well as the motorhome) with the Air Force 1 system, Demco towbar, etc. We chose the AF1 for it's ease of use, as well as the all the good words that have been written in this forum.

Our coach has the Cummins ISL 8.9L 400 engine, with a two-stage compression brake, which I used a bit on our journey. As I was driving home from the shakedown cruise, I began to wonder if the AF1 would activate during use of the compression brake. I know it'll work fine if you actually step on the service brake, but I couldn't determine in my own mind if the compression brake would trigger it as well.

For example, if I am rolling down a long hill, and the compression brake is doing its thing, will the AF1 trigger braking action in the TOAD as well?

Anyone know?

Warhorse6 · 03-22-2021, 12:49 PM

I have an AF1 installed on our chewy traverse. The compression brake does not activate the system and the reason I know is the activation light mounted on the traverse mirror facing the coach does not illuminate. Anytime you hit the brake it does, but that is separate from the compression brake. Safe travels.

FIRE UP · 03-22-2021, 09:20 PM

Quote:

Originally Posted by dwirch

Good morning/afternoon/evening!

The wife and I finished our first shakedown cruise with our new-to-us 2007 Horizon. Since it was just an overnighter, we didn't bother bringing another vehicle with us. For longer trips, we're planning on getting our 2017 Jeep Wrangler JKU (as well as the motorhome) with the Air Force 1 system, Demco towbar, etc. We chose the AF1 for it's ease of use, as well as the all the good words that have been written in this forum.

Our coach has the Cummins ISL 8.9L 400 engine, with a two-stage compression brake, which I used a bit on our journey. As I was driving home from the shakedown cruise, I began to wonder if the AF1 would activate during use of the compression brake. I know it'll work fine if you actually step on the service brake, but I couldn't determine in my own mind if the compression brake would trigger it as well.

For example, if I am rolling down a long hill, and the compression brake is doing its thing, will the AF1 trigger braking action in the TOAD as well?

Anyone know?

dwirch,
A compression brake has absolutely nothing to do with your service brakes. And your Air Force One braking system is ONLY ACTIVATED by your service brakes. It is air activated, not *surge* activated. An example of a surge brake system is the Ready brake system with the cables and all that. When you apply the brakes in your coach, you are sending a given amount of air to each brake chamber to be used to activate your brakes. That same air is also used to activate your Air Force One system.
Scott

vsheetz · 03-22-2021, 10:19 PM

Service brakes only.

Nildecaf · 03-23-2021, 01:46 AM

I considered the impact of AF1 activating with only the service brake and basically determined that would not be a concern provided our GCWR was below the coach rating (which ours is well below). Came down Rt 70 today into Denver (a 6,000 ft decline) with engine brake on and transmission stayed at its normal operating temp for the trip. Used service brakes sparingly where necessary.

Warrenjo · 03-23-2021, 06:20 AM

As mentioned i previous posts, the exhaust brake will not activate the AF1 brakes on the toad. This has the advantage of reduced wear on the toads brakes as well as the MH brakes.

If the exhaust brake is not sufficient to slow the MH and toad then you can apply the service brake and the AF 1 will apply the brakes in the toad so you can always stop safely.

dwirch · 03-23-2021, 07:49 AM

Thanks to all of you for sharing your input.

I figured that the AF1 would only activate with service brakes, just wanted to verify my thinking. What got me wondering about it is would use of the compression brake have a detrimental effect on the towbar.

My thinking was if you're using the compression brake coming down a long slope, say out of the Cascades or the Rockies (I-90, I-70), there might be added stress on the tow bar. I'd hate for the tow bar to snap coming down a hill, just because I was sparing the service brakes.

Or am I just being paranoid?

Cooperhawk · 03-23-2021, 08:01 AM

Quote:

Originally Posted by dwirch

Or am I just being paranoid?

Yup, you are. We've got thousands of miles on our tow bar and not a problem. It's never a severe jolt of the toad, just an easy resistance to the inertia.

Cooperhawk · 03-23-2021, 08:03 AM

BTW, we have AF1 with a Blue Ox. Works great, but I do recommend you run a hot lead 12v to your toad battery.

dwirch · 03-23-2021, 08:16 AM

Thanks, CooperHawk. Appreciate the input, and verification of my paranoia!

Old Scout · 03-23-2021, 08:20 AM

2x on paranoid....take a deep breath, relax and enjoy the ride....think of it this way.... the advantage of your compression brake on long descents is that it doesn't use friction for braking....so if necessary, you can leave it engaged all the way down the grade....you wouldn't want to use you service brakes in that manner nor would you want the towed brakes on all the way down either.

dwirch · 03-23-2021, 08:25 AM

Thanks, Old Scout.

I'm all about the compression brakes. I used them a bit on the shakedown cruise, and have used them previously, in another life. I just wasn't sure how the toad or tow bar would be affected, as I hadn't towed anything in my previous situations. I'm all about that saving the brakes

Cooperhawk · 03-23-2021, 08:26 AM

Take it from an old trucker, don't lean on your service brakes all the way down. What will happen is you will overheat and glaze the pads ruining the effectiveness of your brakes.

Gear down and use either the Jake or Exhaust brake. The rule is to descend in the same gear you would use to climb a steep grade.

Cooperhawk · 03-23-2021, 08:28 AM

Of course while you're carefully working your way down a steep grade you will always see some hot shot go zipping by in a rig like yours ignoring all this advice. It's either one of two things.
1. He, or she is an idiot.
2. They have traveled this grade many times and have a good feel for it.

Problem is you don't know which.