Normally Open Reverse Lockout Solenoid for Disc Trailer Brakes

Updated 02/06/2012 | Published 02/02/2012

Question:

Converting my surge drums to surge discs. Will need reverse lockout, but see you only offer the Normally open style. I would prefer the normally closed bleed off type to reduce loading on the master cylinder when reversing. Is there an advantage to NO style vs: the NC, other than the return line needed for the NC?

asked by: Bill C

Expert Reply:

The normally open style like # T4748800, will only prevent fluid from going back to trailer brakes when you put the vehicle in reverse. Once the vehicle is in reverse, the normally open solenoid will close and allow you to back up without the brakes engaging.

On a normally open system, you will need to be careful when backing up because if you hit a curb or another object it could add even more pressure to the master cylinder and could possibly damage it.

A normally closed system does have the advantage of no putting excessive pressure on the master cylinder.

Since you are switching to disc brakes you may also need larger brake lines. This will allow pressure to build up faster and provide better response time for the brakes.

expert reply by: Michael H