Jerky Brakes (newbie question)

[Pierps]

Hi All!

Rig and TV:
Trailer: 2020 22FB Bambi
TV: 2017 Chevy Colorado Duramax, with built-in brake controller

Problem: My trailer brakes seem to be kind of binary: either "on" or "off". There's a point early in my brake pedal's travel when the trailer brakes kick in really hard. Reducing the gain helps make it less intense, but even at a low gain level, our heads kind of jerk forward when the trailer brakes kick in. It's not really all that noticeable at highway speeds. But it's super annoying in stop and go traffic. The trailer tires aren't totally locking up, but it feels like they're close.

I guess another way of saying it is that there's no nuance to the trailer brakes. It's not behaving like the hydraulic brakes on the truck, where pushing the pedal harder increases the braking pressure.

Admittedly, I have no idea if this is just how electric trailer brakes work, because this is the only trailer I've ever towed that is big enough for its own braking system. So it could be that I have bad expectations. It's been like this for as long as we've owned the trailer since new (took delivery a year ago).

Question: Is this normal? If not, what options do I have to fix it?

Thanks in advance!!!

[GCinSC2]

Pierps,

Lets start with something real simple the settings for the integrated trailer brake controller. Check the manual if needed and review the controller settings for your setup.

Can you review the AS manual too, is it equipped with manual or self adjusting trailer brakes?

Gary

[Ch47d1sg]

did you set the voltage for the brake controller per the set up manual?

Generally you do this by towing the TT at 35mph on a flat dry surface with no traffic and engaging the trailer brake on the controller. This has to be a complete and full twist or slide of the lever to full gain. If the TT brakes do not lock, then you need to increase the voltage gain. It sounds like from your description that the initial voltage is set too high.

Am not familiar with the GM installed controller so really can help there but have heard others generally start at about 6.4.

I run a Prodigy P3 and I have a boost setting that composites for weight of trailer in relation to TV. I have a 7200 truck getting pushed by an 8800lb (max) trailer. The boost setting changes the progressive braking curves to avoid what you are describing. The GM should have something similar I hope

Hope this helps

Top

[uncle_bob]

Hi

All brakes take a bit to "wear in". If you have made it through a few days, they should be past that point.

If Chevy is like Ford, there's only one adjustment on the controller. Back it down to the point you don't get the "jerk". If that's setting 2 out of 10 .... so be it. If there is no setting that still actuates the brakes and eliminates the jerk, you may need to get your local Chevy dealer involved.

Bob

[Bill M.]

Do not know anything about that controller. On my controller there are 2 controls. One adjusts how the brakes respond proportionally to the truck braking. The other controls the initial kick in when the pedal is first pushed. Setting that up makes it really jerky. Setting it down lowers the braking too much. I adjust that gain differently when on the open road or in a town or city environment. I do not know if the Colorado has that adjustment or not?

[Pierps]

Excellent feedback, thank you. I've learned a lot already.

Some answers to questions:

-My trailer has the "Dexter Nev-R-Adjust" brake system
-The Colorado's controller only has a gain setting. No progressive braking curves or anything like that unfortunately. It doesn't ask me for the weight of the trailer.

I definitely did not set the gain properly (at 35MPH). When we picked up the trailer, the Airstream dealer guy told me to just roll forward at a low speed with my foot off the brake, and slide the slider to full gain. if the truck and trailer stop, you're good. From there, he just told me to adjust it based on feel. So yeah, I should have done my own research obviously. I will take it for a test drive next time I'm hitched up.

I can say this though: If I turn the gain on the trailer down low enough to eliminate the jerk at low speeds, I feel like I'm almost completely relying on the truck's brakes. Meaning, my stopping distance feels way way too long and unsafe.

The owners manuals of the TT and TV are both pretty light on specifics. The Bambi's manual says the following:

Proper synchronization of tow vehicle to trailer braking
can only be accomplished by road testing. Brake
lockup, grab, or harshness is quite often due to lack
of synchronization between the tow vehicle and the
trailer being towed, a too-high threshold voltage (over 2
volts), or under adjusted brakes

The threshold voltage piece is something I need to research a bit more. Maybe that has something to do with it?

[GCinSC2]

Something that you can check if you’re comfortable is are the self adjusting brakes actually correctly adjusted?

Raise wheel, spin wheel and feel and listen. A light buffing sound would be normal. Any metal on metal not good. Full inspection merited.

Sometimes the self adjusting brakes need a boost adjustment. Wheel raised, on the inside of the brake backing plate at 6 O clock is a slot should have a rubber plug in it. Remove plug. Using a smaller straight blade screwdriver rotate the star wheel by pushing IN on a tooth at the bottom of the star wheel. Similar but not identical to old school manual adj drum brakes. When you hear good buffing sound or requires more effort to turn wheel stop. Adj other brakes.

These self adjusting brakes work in the forward direction NOT backwards like old pass cars did.

Tweak and test again.

Other issues may be the cause also but this is a start keeping wheels and drums on.

Learning about your trailer brakes if you’re comfortable working with them is a good thing.

Kinda surprised the integrated controller didn’t have settings like light med or heavy trailer etc. but that was a check first item.

Gary

[Ch47d1sg]

Originally Posted by Pierps

Excellent feedback, thank you. I've learned a lot already.

Some answers to questions:

-My trailer has the "Dexter Nev-R-Adjust" brake system
-The Colorado's controller only has a gain setting. No progressive braking curves or anything like that unfortunately. It doesn't ask me for the weight of the trailer.

I definitely did not set the gain properly (at 35MPH). When we picked up the trailer, the Airstream dealer guy told me to just roll forward at a low speed with my foot off the brake, and slide the slider to full gain. if the truck and trailer stop, you're good. From there, he just told me to adjust it based on feel. So yeah, I should have done my own research obviously. I will take it for a test drive next time I'm hitched up.

I can say this though: If I turn the gain on the trailer down low enough to eliminate the jerk at low speeds, I feel like I'm almost completely relying on the truck's brakes. Meaning, my stopping distance feels way way too long and unsafe.

The owners manuals of the TT and TV are both pretty light on specifics. The Bambi's manual says the following:

Proper synchronization of tow vehicle to trailer braking
can only be accomplished by road testing. Brake
lockup, grab, or harshness is quite often due to lack
of synchronization between the tow vehicle and the
trailer being towed, a too-high threshold voltage (over 2
volts), or under adjusted brakes

The threshold voltage piece is something I need to research a bit more. Maybe that has something to do with it?

What you don't want is for the trailer to be pushing the truck before TT brakes are engaged. This can be dangerous. Set the voltage up so that the TT tires are right at lock up using the trailer brakes only at 35.

I had a similar issue when setting my rig up. After messing with the controller I was able to get it to where the TT would engage first and at the right 'feel'. It especially important when th TT weighs more than the truck.... All of this will change when the TV arrives. at 11350 the TT will affect the TV much less

Hope this helps a bit more

Top

[StuartsDad]

The method your dealer told you will work, but they may not have been specific enough. On flat pavement, let truck pull trailer with foot off accelerator and brake. Slide controller to full gain. Trailer brakes should bring rig to a soft, smooth stop, no jerk. Dial up or down to find it. I like this method because it's easy to check every time I hitch up.

[uncle_bob]

Hi

The brakes on these trailers are not anywhere near as good as what's on your truck. Most of the braking should be done by the truck brakes. If you set things up so that the trailer brakes "contribute" a lot to the result they will ..... errr ... break. I have data on this ....

Bob

[Il Bambino]

Hi

I had a similar combination: 2016 GMC Canyon/Duramax with a 2017 19’ International. (We currently have a 20’ Caravel on order)

Once every 10/15 restarts the trailer brakes would “grab” severely. (Even a a very low speed parking lot situation) I would have to turn the truck’s ignition off and unplug the 7-way, wait about a minute and restart and that usually fixed the issue. The gain was mostly happy at 7.5 with the factory brake controller. I kept the 7-way clean and coated with dielectric grease.

Jackson Center inspected the trailer brakes and found no issues. I think it’s an issue with the truck. The Airstream was the only trailer that I have towed with the Canyon. We’re a couple of months away from delivery on the new trailer so I’m afraid I can’t provide you with any more information.

J