Should New Trailer Brakes Pulse at Low Braking Application

Updated 04/17/2017 | Published 04/15/2017

Question:

Just installed these on my trailer. It did not previously have trailer brakes. I am very pleased with how quickly they were shipped and will be using you guys again as well as telling my friends and family how convenient and fast your processes are. Everything went smoothly on install and it was a quick job. Upon testing the brakes it took about 30 miles for them to start grabbing, I assume this is normal as the shoes take shape to the drums. On the next trip out, however, I noticed a sort of throbbing or pulsing. The brakes do catch in some spots when I turn the wheel I noticed this when doing the initial adjustment. Could both drums be out of round from factory? Or is this something that happens as they are breaking in and it it a new shoe/new drum issue? More info. It seems to start as the brake controller hits about 15-20 on the display it stops pulsing at higher than 25 and I get lock up at about 35-40 its a fairly light trailer when not loaded at about 1,200 lbs. added a new junction box and ran 12 gauge wire to brakes. Grounded the brakes to the trailer body.

asked by: Thurston J

Expert Reply:

The assemblies you have are most likely self adjusting assemblies that tighten slowly with each brake application until they are grabbing lightly all the time. Not enough to slow you down but there will be a light drag as the drums glide on the shoes.

Since your brakes seem to be more capacity than you need it's not going to take much braking power to get them to start feeling them slow you down. Most likely what you are experiencing is brakes over rated for your empty trailer and them being new and needing to clearance themselves with more mileage.

You might pull them off to make sure your drums aren't out of round or the assemblies are looking fine. If everything looks fine just keep driving and keep an eye on it. If the problem gets worse you may have something going on but I would predict it getting better.

expert reply by: Jameson C