Why Aren't Hydraulic Brakes Locking Up When Backing Trailer Up Hill When Unplugged from Vehicle

Updated 09/06/2019 | Published 09/05/2019

Products Featured in This Question

Demco Hydraulic Drum Brake Assembly - Single Servo - Galvanized - 10" - Right Hand - 3,500 lbs

(51)

$67.09

Replacement Solenoid Valve for Dexter Brake Actuators with Reverse Lockouts

(283)

$87.70

Question:

My brakes do not lock the wheels when backing up a hill when unplugged from the vehicle. Have A60/A-75 UFP actuator. can it be a bad solenoid or other part?

asked by: Gary

Expert Reply:

It could potentially be a bad solenoid on your actuator that was closed shut that's preventing the brakes from engaging in reverse on your trailer, but there are a few other possibilities that you can check as well.

I'm not sure if you're backing up with the trailer unloaded (or if it's just a really light trailer) but if it's not heavy enough and the hill isn't steep enough, it simply might not be creating enough pressure to activate the brakes. If it's unloaded you can try loading up the boat or any other cargo to see if maybe this has a different result.

You could also just have free backing brake assemblies or a manual lockout on the actuator that doesn't require the tow vehicle's reverse circuit to work. Of course if the trailer brakes engaged in this same situation before then this wouldn't be the case.

We do not currently have any replacement solenoids for your UFP model actuator.

expert reply by: Chris R