This weekend's campsite wasn't level, as it was sort of an incline. Got the travel trailer hooked to the truck, took off the parking brake, and I noticed the trailer brakes were fully engaged (per the gain meter on the dash). I left my foot off the truck brake and it took about a second or two for the truck to release the trailer brakes. I also noticed the truck brake pedal was really hard to push down.

Kinda cool, I thought... but wondered if anything can be damaged by pulling out before the brakes release. It happened again near home as I sat on a hill at a red light... Took my foot off the brake and the trailer brakes took a second to disengage.

So, assuming this is normal functionality, do I need to wait until the truck releases the trailer brakes, or is it ok to step on the accelerator pedal as usual when the light changes?

 

It's a nice feature our trucks have that you just don't appreciate until you tow with something else. Brakes will release as soon as you hit the accelerator.

 

It is normal. I feather the accelerator and the brakes will let go.
No damage other than a very light amount of brake use over the life of the brakes.
I still two foot drive in these situations because I forget but Ford designed it so you have time to get your foot from the service brake to the accelerator.

I wouldn't floor it though.

It will do this without a trailer also if the truck is on an incline.
It is handy at times, annoying other times without a trailer.

 

Brilliant.

Thanks.

 

I replaced the brakes on my trailer before my drive down from AK.
while adjusting them I could not get them to lock up when applying the gain lever by hand (with the gain set to 10) in the gravel, I jacked up trailer to make sure they were adjusting and the brakes were so tight I could barely move the tire by hand, slacked them back off and readjusted.
I could feel them working on the pavement, just couldnt get them to lock up with the gain turned all the way up and applying by hand.
So that tells me the Truck can "anti lock" trailer brakes as well ?????
I did have someone pull out in front me and had to get on the brakes HAAARD, and after I got calmed down and regained my composer I thought I had heard the trailer tires chirping.
So any one know about truck anti locking trailer brakes....

 

if you have tow/haul on, the electric trailer brakes become integrated with the truck braking control, and will get ABS treatment.

I love this feature, along with brake control, the auto downshift engine braking is really amazing.. saved me a couple times when idiots pulled out in front of me.

as I understand the manual mode, the truck KNOWS when you are not moving, and so doesn't turn on the trailer brakes.

Sam

 

My trailer brakes are active when stopped if I press the brake all the way.
Mine have a slight hum on the trailer if I fully press the brake.
I wonder if this is a newer year feature?

 

For reference, this is impossible. There are no tone rings or other sensors on the trailer wheels for the ABS computer to figure out they're locking up and let them go. If you see dashed lines of trailer tire skidmarks after a panic stop, it's because the wheels are hopping, not because of the world's most rudimentary ABS (which even the most basic won't leave any skidmarks at all).

 

he was pressing the manual level he said. not the brake pedal.

 

I believe the Trailer brake control integrates with ABS... but that said, the only way that I can think of it doing that is if it detects the truck wheels locking, it would pulse the trailer brakes like it does the truck brakes.

If the truck wheels aren't locking, I would assume that it would still lock the trailer brakes.

 

That's a cool feature for sure... and taking it even further... the wife's audi had that engine stop feature when you came to a stop the engine would shut down....
I HATED it, but she liked it ...

at any rate, IIRC the brake pedal was the key - as soon as you engaged the brakes @ 0 mph, the engine would shut down, then when u took your foot off the brake, the engine would start and by the time you got to the accelerator, the engine was running !

 

Must be a really robust battery and starter system for that to work... now is there a time hysteresis to prevent constant start stops when you're in traffic? It works on hybrids because they can crawl forward without ever starting the engine.

 

A number of European cars have it now-a-days. I have only driven ones with a stick, where if you put the transmission in neutral and the clutch isn't pressed below 2mph, it turns the engine off. As soon as you press the clutch to put it back in gear, it fires it back up.

I am not sure if it was distance based, or time based, but if it was a short distance btwn stops, it wouldn't turn off a 2nd time.

Like John, I found it a PITA, and would disable it. Not sure if its fitted to diesel engines, given they take a lot more to start (stronger starter & glow plugs)

 

No, I don't think so, because the truck has absolutely no idea how the trailer brakes are behaving. In the truck, there are sensors at each wheel to tell it exactly how each wheel is behaving, and it doesn't just "pulse the brakes" but reduces the applied braking pressure at each separate wheel until it starts rolling again and then increases pressure back up toward the driver's input through the pedal until that wheel locks up again and then reduces pressure, etc, many times per second. For each wheel, independently. This action is especially important for the front wheels, as those are the ones that direct steering input. ABS is not about reducing braking distances but maintaining as much as possible the ability to steer even during panic braking (as compared to steering input having little or not effect at all when the brakes are locked up) and to reduce oversteer/fishtailing, where the rear end comes out of line with the front of the vehicle and can cause unintended directional changes or result in a roll-over. There is no mechanism for communicating to the truck whether one or more trailer brakes are locking up, nor any ability to reduce or increase braking pressure to individual wheels.

If you take a light, strong trailer with strong brakes and a heavy load and have to adjust the gain up to max so that it helps slow down all that weight behind you, then you unload the trailer and drive away, there's a good chance that the trailer brakes will lock up as you approach a stop sign or red light or have to slow down quickly on a highway off-ramp. Conversely, if that same trailer empty would lock up at, say, 7, and you set it to 7.5 to be sure, then loaded the trailer down, suddenly that same amount of braking force would not be enough to lock them up anymore, and you'd have to ratchet up the gain to get it back to normal. You should try this the next time you're hooked up to an empty trailer with good brakes in a fairly safe and controlled environment. Dial the gain all the way up, start rolling with a little speed, and then press the brakes. You'll see there's no trailer ABS.

I'm sure if it were viewed as a problem and the results would be profitable, then the manufacturers of electronic brake controllers and axles/trailers could get together and define a standard for giving a trailer its own ABS. It still would have nothing to do with the truck, because there's no existing mechanism for providing brake behavior feedback to trailer brake controllers. It wouldn't have to involve the truck anyway since it could manage it all on its own. I'm not a big rig driver, but I've never heard of them bothering with anything like that on big rigs, even, which cost a ton more money with a lot more to lose and weigh a lot more.

Then again with the prevalence of bluetooth technology, even in radar detectors and GPS devices and whatever else, maybe in the future brake controllers will have built-in bluetooth and smart trailer brake controllers when plugged into the 7-way power could connect and communicate a whole lot more information, even about wheel conditions, so that the gain could be adjusted automatically, etc. That's probably a whole lot more complex than it needs to be, which is part of the reason it hasn't already taken the market by storm.

 

Abs on trailers have their own module separate from the truck and use the center pin "blue wire" for power on an 7-way recepatcle. I have only seen these systems on tractor trailers.