Brakes actuator - Montana Owners Club

gchesnutt · 12-25-2023, 10:15 AM

Can anyone help me locate the brake actuator on my 2021 3761fl?

**AZ Traveler** · 12-25-2023, 10:27 AM

Glenn,

There is normally a manual brake actuator with your brake controller in your truck. There is also an emergency brake actuator on the kingpin of the rig that is hooked via a cable back to your truck in case the rig disconnects from the truck.

I am not clear what you are asking about.

DutchmenSport · 12-25-2023, 11:21 AM

I don't understand what you mean by "actuator". An actuator is a device that moves along a set track, back and forth a set distance. They are used in electric recliner chairs and such. Never heard of anything like that for brakes on a vehicle.

If you are wanting to know how to activate the brakes on the trailer, there are only a couple ways.

The first is to push the brake peddle of the tow vehicle. An electric charge is passed through the pig tail plug on the trailer and activates the brakes. The brakes are electric, and DC electricity activates them.

The second way is to pull the cable on the brake-away switch found on either the trailer tongue or the King Pin Box on a fifth wheel. When the cable is pulled, a pin inside a little box is pulled out. This allows an electric circuit to activate the brakes. This switch is powered by the battery on the trailer itself. The brakes are powered by the trailer battery too.

The purpose for the brake away cable / switch is in the event the trailer separates from the tow vehicle while in motion, the pin will pull activating the trailer brakes, stopping the trailer in a controlled fashion.

You can pull that pin yourself to test the brakes. When you do, you'll hear an electric hum at the brakes themselves. But, you don't want to leave that pin pulled for any length of time. The constant electric draw on the brakes will drain the battery and can burn up the electronics of the brakes themselves. They are designed to stop the trailer when in motion, not hold the brakes on indefinately when parked.

If you need the trailer wheels secured, then you chalk the tires with wedges or tire chalks. No matter where, and under every condition (even perfectly fat surfaces), you should always chalk the tires, front and back directions to prevent the trailer from moving.

MandK · 12-25-2023, 12:09 PM

If you have a legacy, the disc brake actuator is usually in the compartment near the batteries or in one of the propane compartments. But when we were at the rally this year, I wanted to see what actuators keystone is using and neither the Tiara salesman or I could find the actuator on the legacy model they had there. It definitely was not in the front compartment

gchesnutt · 12-25-2023, 01:21 PM

Thanks for the replies. I was asking about the controller/activator on the trailer. Mine is not a Legacy but I can find nothing that looks like what I am looking for.

**AZ Traveler** · 12-25-2023, 01:22 PM

Do you have disk or drum brakes? What is the issue you are sorting out?

gchesnutt · 12-25-2023, 02:01 PM

My 2021 3761fl is new to me. Towing with a 2020 gmc 3500 Sierra. The trailer brakes don't seem to work at all, but did work with my previous 37' outback. I am not sure what brakes the Monty has but have been told this model comes with electric/hydronic drum brakes. According to what I have read on this forum and others, electrical/hydronic brakes are not compatible with any gmc, ford, or ram oem controller. Etrailer has an adapter that can be mounted on the trailer to make it compatible but they need the model and serial# of the controller on the trailer to check compatibility. So far I have not found the controller in the front compartment or propane compartments.

**Carl n Susan** · 12-25-2023, 02:23 PM

Lets's start at the beginning. What brakes do you have? Look at the brakes behind the wheel spokes.

Do they look like these Drum Brakes?

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*OR*

Do they look like these Disc Brakes?

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A non-Legacy likely doesn't have Disc Brakes. Drum Brakes are standard. There is no controller on the RV for Drums. Drum brakes are compatible with any truck controller whether integrated or stand alone.

Electric/Hydraulic refers to Disc Brakes. There is a hydraulic controller on the RV for them.

**AZ Traveler** · 12-25-2023, 02:25 PM

Glenn,

Your rig likely has drum brakes. When you look through the wheels you will see either a disk or drum to be certain.

Assuming drum brakes, the controller is part of the truck and there is not a controller on the trailer. Pull the book out on your truck and read up on trailer brakes. As I remember GM did have some issues with disk brakes but not drum brakes. If that doesn't work hire a mobile tech.

gchesnutt · 12-25-2023, 04:18 PM

I do have drum brakes so it is back to troubleshooting the electrical system to the magnets. The wheels do lock when the emergency cable is pulled.

MandK · 12-25-2023, 04:35 PM

If the breakaway switch activates the brakes, then the problem is in the truck or between the truck and pinbox. The breakaway switch is wired into the trailer brake line in the pinbox junction box. Pulling the breakaway completes the circuit between the trailer batteries and the brake wire in that junction box, sending 12v to the brakes. Start checking things at your 7 pin connector.
The picture below shows the blue wire (brakes) from the pigtail that plugs into the truck attached to the blue brake wire of the trailer. The black line is the line from the breakaway switch that powers the brakes when the pin is pulled. So, if the brakes work when activating the breakaway, you know everything is working from there back to the wheels.

prndl · 12-26-2023, 10:15 AM

Does your truck have a factory trailer brake controller? If so have you tried to set the gain on the controller? Does the manual slider (pinch) lever work in the truck?

Todd & Mary · 12-26-2023, 01:29 PM

Drum brakes have no central device, they are wires to the 7 pin and the truck operates the brakes. If, as you have said the breakaway operates the brakes the issue lies between the truck and trailer or in the truck brake controller. You may have to set the gain up higher to actuate the brakes a noticeable amount. If i remember correctly I ran the gain on my ford at 9 when i had drum brakes on my 3761FL. With my new disc brakes it is set at 6.5

BobM · 12-31-2023, 02:14 PM

On the GMC 2020 Sierra, you need to modify the settings on the dash info display. Create a profile for your rig. Weight, length, height, etc. and as mentioned, set the brake gain. Once you create the profile it is good until you change the rig. That should fix your problem.

Speck56 · 12-31-2023, 02:25 PM

The brake master cylinder is in the battery compartment. Towards the rear of the compartment. My 2020 3761FL had a leaf spring break that severed the brake hose and all hydraulic fluid. Not fun stopping without brakes

gchesnutt · 12-31-2023, 02:43 PM

Thanks for all the comments and suggestions. The problem turned out to be the 7pin connector in the bed of the truck. The break pin was shorted. After cleaning and greasing the connectors everything seems to be working normal. Won't know for sure until I hit the road again. At least I know now that if there is a problem, I can connect to the bumper 7pin and all is well.

Rhortie1 · 12-31-2023, 03:22 PM

Quote:

Originally Posted by gchesnutt

Thanks for all the comments and suggestions. The problem turned out to be the 7pin connector in the bed of the truck. The break pin was shorted. After cleaning and greasing the connectors everything seems to be working normal. Won't know for sure until I hit the road again. At least I know now that if there is a problem, I can connect to the bumper 7pin and all is well.

Just fyi for the future, my 2019 oem brake controller is not compatible with E/H brake systems. I had to install an aftermarket controller in my 2019 but I have the Legacy package.

jelders25 · 12-31-2023, 06:18 PM

Hello from OKC, I had the same problem on my 2020 Legacy but was insistent on using my factory controller. I like all the factory options that are built into it. Did you know about the Dexter service bulletin #010, dated May 28, 2020. Dexter part number K58-036-00 E/H compatibility adapter fixes the issue we were having.

Rhortie1 · 01-01-2024, 07:05 AM

Quote:

Originally Posted by jelders25

Hello from OKC, I had the same problem on my 2020 Legacy but was insistent on using my factory controller. I like all the factory options that are built into it. Did you know about the Dexter service bulletin #010, dated May 28, 2020. Dexter part number K58-036-00 E/H compatibility adapter fixes the issue we were having.

Unfortunately I bought my rig before this bulletin came out and once I paid for the aftermarket controller I just kept it.

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