Troubleshooting Trailer with One Hub That Locks Up Even with Low Power on Brake Controller

Question:

hello I am going thru tires on my front axel, I have a 40foot pj trailer with dexter axels 12000# I took the trailer to our mechanic and he wants to replace all 4 hubs, magnets, everything he said my hubs have leaked oil and the other 3 that arent locking up are oily. My hubs havent leaked any oil, he just replaced everything a year ago and I have had the issue since then. I am running my brake controller at a 3 and one hub keeps locking up. I have tightened the other three brakes. They work but the one is still locking up. I cant up then fake controller at all or I am smoking my tires. I would like to save some money and fix it my self. I feel our mechanic just wants to replace everything to make more money. Do you have any tips I can try before I replace everything. I thought about just clipping the wires on that hub and just using the other 3.

asked by: Joel B

Expert Reply:

On a trailer as large and heavy as a tandem-axle 40-footer you really do want all four hubs delivering braking force.

Wheel bearing grease, or oil from an oil-bath type hub, can certainly damage drum brakes. Usually such leakage will cause reduction in braking power because the grease/oil reduces the pad-to-drum friction that provides the braking force. Grease- or oil-contaminated brake assemblies do need to be replaced; it is not really possible to clean them out properly if they actually did get loaded with oil. Hub/drums can certainly be cleaned and should not require replacement just due to oil exposure.

Since you have one brake locking up I suggest carefully inspecting it for signs of broken components (or the oil contamination). If you're lucky you may simply need to adjust the star wheel on the brake to reduce its tension so it does not lock up. If you pull that hub from the problem brake and also another to compare it to this can make finding the problem a little easier since you'll have a good one to use as a guide. Electric brakes do have a few components, like springs, that can break or wear out.

Installing a new electric drum brake is not tough. You have to mount it to the flange and wire the two magnet leads. Either wire can be grounded or used a hot. I linked our main page for electric drum brakes. Select them based on the individual axle weight rating. In the 12K axle capacity we have 12-1/4 x 5-inch and also 12-1/4 x 3-1/2-inch left- and right-hand kits like # AKEBRK-12 as well as individual assemblies.

expert reply by: Adam R