Check your breakaway brakes!

ScottGScottG Moderator Posts: 3,506
edited May 22 in Trailer & Towing
For all the discussions we have had on properly providing power to the breakaway brakes, we rarely if ever give much consideration as to whether they actually work as designed. While some of you may be diligent about such matters, I confess I have never actually pulled the pin from the switch box to see what happens. Until today.
And what happened was... nothing. No drop in battery voltage under load. No locking of the wheels.
It seems the little switch into which the pin inserts gets a bit arthritic with age. After cycling the pin in and out several times--and applying a few taps to the switch housing--the brakes started engaging.
So, if you don't regularly check your breakaway, I suggest you give it a go. I'm thinking my switch might need replacement of at least a little TLC to clean up the contacts inside.
Anyone else experience this, and if so, what did you do to remedy the situation?


  • Sharon_is_SAMSharon_is_SAM Moderator Posts: 5,196
    Good reminder!  Thank you @ScottG.  Our pin is very difficult to pull out.
    Sharon / 2017 [email protected] CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
  • ScottGScottG Moderator Posts: 3,506
    Yes, the pin is pretty substantial and requires a hefty tug. That's good, though--not something you want coming out at the wrong time!  :-0
  • BrianZBrianZ Member Posts: 1,082
    I've read elsewhere that the force required to pull the pin is about 40 lbs.  Also, once pulled and brakes are active, there will be a substantial drain on the battery, like 6 amps or something, so it wouldn't take very long to kill a battery - just something of which to be aware.
    -Brian in Chester, Virginia
    TV: 2005 Toyota Sienna LE (3.3L V6)
    RV: 2018 [email protected] 320S, >70 mods 
  • ScottGScottG Moderator Posts: 3,506
    I didn't measure the force required to pull the pin, but I'm pretty delicate and I could do it if I looped my thumb through the cable for a better grip.
    I also don't have any fancy monitors, but my battery whispering skills suggest the load was less than  I anticipated. My marginally good battery dropped from ~12.45V at no load to ~12.05 with the brakes engaged--a substantial draw but comparable (or even less then) running the water pump. The battery recovered normally after the load was removed.
    A tag on the cable says don't leave the pin out for more than twenty minutes, but I wonder if that has more to do with frying the brakes themselves rather than draining the battery.
  • tabiphiletabiphile Member Posts: 171
    Part of your annual maintenance should be making sure that the breakaway is serviced/tested. After you have lubed your hubs, replaced the wheel, adjusted the brakes you should test the breakaway. Do this by pulling the pin and then spinning the wheel (the wheel should be jacked up). If it spins, it's not working. If it locks up you can move on to the other side. With the pin out it is a good idea to give the contacts in the switch a spray of contact cleaner (CRC contact cleaner)...that will assure that the switch contacts don't corrode. @ScottG , what you were doing by pulling the pin out and then putting it back in was cleaning the corroded contacts.
  • pthomas745pthomas745 Member Posts: 1,189
    I took my trailer out for a spin around the freeway just for fun the other day, and played with the emergency brake. 
    Yes, it takes a real pull to get it out.  Thanks to Tabiphile on the hint about a shot of contact cleaner.
    In the interest of science, I used my fancy Victron this morning for the power usage of the emergency brake.
    Before the plug was pulled is the left side, reading with the plug out is on the right.  I waited a couple of minutes for the reading to settle down a bit.
    Brian Z was correct.
    6 AMPS! 

    2017 Outback
    Towed by 2014 Touareg TDi
Sign In or Register to comment.