Disk brakes on trailer stuck full on.

[REW]

My nephew has a fairly larger boat with surge disk brakes on it.

He complained about the fact that the brakes were stuck hard on.

It was suggested to him that the calipers were the problem, so he replaced the calipers and rotors and still has the issue.

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I don't know the make or model of the trailer, nor the brand of the brakes.

But, it has been suggested that the surge assembly that contains the master cylinder is likely the issue with the brakes.

Or, can just part of the assembly be replaced like the master cylinder or some other part of the front end actuator?

Take care

[REW]

I have had a couple of friends with similar problems and they just bit the bullet and spent the money to buy the new front end for the trailer that contains the hitch, actuator, master cylinder and electrical lock out.

Changing out the entire actuator did repair the issue for each of the folks.

Any other suggestions?

Take care

[Hot Runr Guy]

REW,
Something doesn't make sense. If he replaced the calipers, he would have had to go thru a refill & bleeding of them, which would have been difficult to do with a bad actuator. Most disc-brake actuators have a reverse-lockout solenoid on them, to prevent pressure from being sent to the brakes when backing up, activated by the backup-light circuit. I'd look at the solenoid circuit, to make sure it's not being activated when it shouldn't be, trapping pressure.

Here is a link to a typical actuator manual, with troubleshooting and parts breakdown. https://www.google.com/url?sa=t&rct=...I3s6XbLgBN2LK7

Also, is the trailer level when towing? A nose-down position will tend to put pressure on the ball, thereby putting pressure on the braking hydraulics.

HRG

[MikeF]

As HRG has mentioned, I would start at the solenoid.


Some reverse brake solenoids use a single wire setup, usually blue.

The wire supplies the 12V + and gets the ground connection from the mechanical connection of the solenoid body to the trailer frame.

Check the trailer frame ground connection if the solenoid is a single wire type.

Also check if the trailer has a pressure release tab under the actuator as in the UFP models.

Also check to see if the emergency cable been pulled out by accident.

Good luck

[Wrktfsh]

If the calipers are new then the only thing it can be is the actuators-master cylinder

[muskyed]

Any chance that he has pulled out the emergency brake cable on the trailer? There is a reset latch, underneath, , just behind where your ball goes into your hitch, there is a button that you push in to reset it, If that little black cable has been pulled out, your brakes will remain locked up till you push in on the reset.

[REW]

Thanks for the comments and thoughts.

I don't have the trailer close and I don't have the unit to check. I copied the responses and sent them on to my nephew for follow through.

He is a surgeon who practices in Ill, so if it is reasonable, he will take care of the issue. But, if there is the slightest risk to his hands, he will hire the job to be done. One slip of a wrench and there goes his career.

Thanks again, I expect that he will use these comments for the resolution for the problem.

Take care

[Bobby Winds]

I would suggest he trade the trailer in for a better trailer that doesn’t have bad brakes.........problem solved.......

[Diesel Pro]

One thing to verify is that nobody recently added fluid. While not common I've seen where someone not so mechanical has added a petroleum based product like power steering fluid. This swells the silicone rubber and will lock things up tight. Pop the cap and if the rubber is about 4x it's normal size...