Disc brake actuator behavior

[bikerdavet]

Installed the disc brake kit. When bleeding the brakes the actuator pump seems to work fine with the hand control of the OEM brake controller. With the brake pedal the actuator pump works great the first time the brakes are applied. After the first application of the break pedal very little pressure us applied to the brakes. First applicant of the pedal locks up the brakes. Hit the pedal a second time and I can spin the trailer tire but there is drag from brake pads. The OEM hand control locks the brakes every time. Have not driven the truck and trailer to test. This is testing with the trailer on jacks. I am concerned about taking it on the road from a safety perspective. I read that the OEM brake system has a built in feature that proportionally applies the brake. I wonder if the OEM system is causing the behavior of little braking/resistance when applying the brakes? Any ideas? Thanks

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[vonzoog]

When using the hand controller in your truck and by moving the control all the way, you are applying full electrical power to the actuator motor. If you controller is set at low settings (1 to5) then you are only applying half or less power to the actuator when applying the brakes.

Your OEM controller may have the option to set the controller to the type of brake system you are using. In your case it would be “Electric Over Hydraulic”. Check you owners manual on how to set this up. After you have done that you will need to road test to adjust the controller for the weight of your trailer.

[bikerdavet]

Thanks. The system is set up for electric over hydraulic with the system set to high for trailer brake effort. Gain is set to 10. So everything on the truck appears to be set up correctly. 2017 Ford F350 with integrated controller.

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[FT4NOW]

Thanks. The system is set up for electric over hydraulic with the system set to high for trailer brake effort. Gain is set to 10. So everything on the truck appears to be set up correctly. 2017 Ford F350 with integrated controller.

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What is the speed of the truck when you are trying this? I remember reading Ford TBCs dont activate the trailer brakes below a certain speed; I dont remember the setpoint though.

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[cfowler55]

I believe I remember reading that no voltage is supplied when stopped. This is to prevent continuous running as when sitting stopped with your foot on the brake. I still have factory brakes so I'm recalling this from when I was researching install procedure.

[bikerdavet]

What is the speed of the truck when you are trying this? I remember reading Ford TBCs dont activate the trailer brakes below a certain speed; I dont remember the setpoint though.

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The trailer is on jack stands and blocks. So we are not driving down the road. This is happening when bleeding the brakes. Really hesitant to test drive if the brakes won't apply when going down the highway.

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[Cate&Rob]

What is the speed of the truck when you are trying this? I remember reading Ford TBCs dont activate the trailer brakes below a certain speed; I dont remember the setpoint though.

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x2 on advice from FT4NOW. Since the trailer is still on jack stands, truck speed is zero for your testing. The truck does not apply the trailer brakes below a minimum speed. If it did, your trailer actuator would be running almost continuously in stop-and-go traffic. From what you describe, everything is correct. Just tow cautiously for the first little while to confirm.

Rob

[bikerdavet]

Okay that makes sense. No speed no actuator pump running. Thanks for the great replies. I just don't want to put anyone in the danger with my DIY install.

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[Cate&Rob]

Okay that makes sense. No speed no actuator pump running. Thanks for the great replies. I just don't want to put anyone in the danger with my DIY install.

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You have confirmed that you can apply your trailer brakes with the manual control in the truck. This is your fail-safe. You are good to go .

Just a further thought . . . after my installation, braking was way better than the original electric brakes . . . but, I noticed that the dacromet disc coating was wearing off faster on one side of the trailer than on the other. The side with faster wear was the "first" side fed by the hydraulic system. So . . . one more round of bleeding the brakes and the trailer braking got even better and the dacromet quickly wore off the "second" side.

There are inevitably small air bubbles still in the system even when it will seem to apply the brakes.

Rob

[Jerryr]

Thanks. The system is set up for electric over hydraulic with the system set to high for trailer brake effort. Gain is set to 10. So everything on the truck appears to be set up correctly. 2017 Ford F350 with integrated controller.

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I had same 2017 F350 truck with the same controller and trailer disk brakes. My 2019 is also the same. As others stated, you need to get over 10-15 mph before actuator fully engages trailer brakes proportional to amount of pedal pressure you apply. That's Normal.

Set the controller to medium effect and gain to 6 to start. Then take it out for a test drive. Test the brakes with the brake pedal at about 40 MPH with a normal stop and see if you need more an or less. Gauge this by the amount of brake pedal force you need.

Then change system to High effort and see if it feels better. From what I understood, the Low-Med-High setting is how fast the the initial brake effect comes in when you apply brakes.

I cannot lock up even my disk brakes with the manual controller on dry pavement. But pedal effort is the same with or without the trailer attached. In panic stops the trailer will lock up.