Total brake failure

[Albertaslim]

My 2017 RiverStone Legacy has experienced a complete failure of the Dexter electric over hydraulic disc brakes.

I was travelling on a road with minimal grades and not using the trailer brakes when I pulled into a rest stop and discovered that the brakes were very hot.

i waited for the brakes to completely cool and managed to get to my destination.
I called a mobile tech.

3 of 4 callipers, pads and rotors are wrecked and one rim was scored when the calliper dropped onto the rim.

Parts are on order to rebuild all 4 brake assembly's but before I complete repairs I would like to determine the cause of the failure.

I have checked the break away switch and the settings on my Ram brake controller. Both okay.

Any other thoughts?

[SeaDog]

I don't have that system but as I understand it when the trucks brakes are applied voltage is sent to a hydraulic motor which in turn provides hydraulic pressure to the disc brakes. I think I would start by hooking up the truck stepping on and realizing the brakes and then check for continued operation of the hydraulic pump. This is a guess on my part so take it for what it is worth, but I think its a starting place.

[TitanMike]

Over the years a common failure in disc brake systems was hose damage internally. Brakes would be applied but when released the inside of the hose would block the return pressure keeping calipers pressurized and brakes dragging (or even locked up).

Since the problem appears to be with all four calipers dragging, give a good look at any hoses on the main pressure line from the controller.

Older Chrysler products with disc brakes were notorious for this problem where the inside lining of the hoses supplying the caliper would form sort of a check valve. Was only revealed when hose was removed and air blown through from each direction.

[Albertaslim]

Thanks for your suggestions. At this point I don't have any brake fluid in the system so I'll have to wait until the repairs are completed to check out the actuator and lines

Hopefully the tech can inspect the lines while bleeding the system and give the actuator the once over.

Happy holidays.

[5picker]

Had this system been working fine up to this point?

2017... did you ever have to add fluid or make any recent adjustments?

For it to completely 'wreck' (your words) 3 of the 4 calipers, rotors and pads, it had to have been dragging for a while.
Did you notice anything different in the way it pulled?

Had you ever checked the pads?
Maybe they wore out and it was metal to metal for a while?
That would certainly make them hot even under just normal driving with no pad material. I've seen car calipers pulled right off the vehicle with metal to metal conditions.

Any wiring done recently?
Any changes to your 7 pin?

[Albertaslim]

Thanks for your ideas 5Picker. I didn't notice any difference with towing or braking up to the point I pulled into the rest stop. At that point it was very obvious that something was wrong.

I check the fluid level from time to time and haven't had to top up. The 7 pin appears okay and there has been no wiring work.

The trailer has just under 10K miles since new and the brakes have worked very well up to this point.

I run 4 to 4.5 gain on the factory brake controller.

The good news is that I am stationary until late March. The bad news is that I am going to have fight with extended warranty for coverage.

[Qwkynuf]

I hate to be the one to ask this question, but how many feet do you use to drive? If it's only *ever* your right foot, and you move it to the brake when you want to slow down, then never mind.

But if you use your left foot for braking and your right on the gas, then even a little tiny bit of "resting" your foot on the brake pedal is likely going to put that 4.5 gain to use on your trailer anytime you are moving. And your brake lights are probably on nearly 100% of the time.

I have known quite a few two-foot drivers, and every one swears that they never touch the brake unless they are slowing down... but I have watched a bunch of them accelerate away from a stop light with all 3 brake lights staring at me!

[Hclarkx]

I suppose it's possible the controller in the truck might have a problem. Maybe some leakage that puts a few volts on the trailer brake line when no brakes are applied. I'm thinking to check the voltage of the brake pin in the 7-pin connector when the truck is idling. Ideally this would be done with the trailer connected, especially if the truck has trailer detection; but that might not be essential.

[Albertaslim]

I am going to have the factory towing package checked out. Hopefully they can run a diagnostic to see if there is a problem.

My brake issues came on very quickly and I agree with you that it may be based with the controller or wiring.

[jrk341]

I would also call Dexter to see if they have had this problem before. They are a great customer service company.

[Albertaslim]

Thanks. I will give them a call.