New brakes are weak.

Paul1959

I did a brake job on my 2018 T@b 400.  I am new to trailer brakes, so I had some learning to do.  I replaced both the brake and Hub/drum assemblies.  So all new parts.  Re-assembled and adjusted brakes.  Did the Dexter recommended burnishing process with 30 brake applications to drop by 20 mph speed.  Controller gain is still at maximum.  I do not have confidence at this point that the burnishing helped increase performance.  I did check the current from the brake controller and it showed 8A at max setting.  So, I believe that electrically it is working correctly.  The brakes do not seem "grabby" as some have complained.  Rather the opposite.  Does anyone have any thoughts as to what else I can try?  I have about 70 miles on the new brakes at this point.

pthomas745

Keep adjusting until it is right. Or, better.

This thread?

https://tab-rv.vanillacommunity.com/discussion/5483/brake-adjustment

And, then this thread about brake and controller adjustments. You don't say what controller you are using.  One comment here discusses the possibility of a bad controller.

https://tab-rv.vanillacommunity.com/discussion/10322/new-to-electric-brakes

rh5555

When I got all-new brakes when my axle was replaced it took way, way more than 30 brake applications to bed them in.  More like a trip to Arizona and back.  I had same symptoms - brakes just seemed weak no matter how I adjusted them.  One they did start to bed in, it seemed like an exponential process - they got better and better quite fast (as I backed off, and backed off the brake controller setting).  Just be patient (and go on lots of trips!).

fstop32

Way back in a previous life I worked for Sears in their auto center (college job) and when we did drum brakes part of the process was to measure the inside diameter of the freshly turned brake drum.  We would then mount the shoes on a machine and matched that measurement to "arc" the pads to match the arc of the drum.  This process insured the best contact surface to surface and stopping ability from the get-go. 
@Paul1959, if you didn't have someone arc the shoes to match the drum that would explain the "weak" braking response you are experiencing.  You probably only have a small portion of the shoe actually contacting the drum.  Were you to pull the drum and examine the shoes you should be able to see where the shoe is contacting the drum.  Also, the surfaces of the shoe not making contact with the drum will probably have a layer of dust produced as the pad on the shoe wears down.  Over time the shoes will wear to fit the drum, however sometimes the pads on the shoe will "glaze over" from excessive heat due to the small contact surface area and will not have quite the stopping power available.  You can hand sand that glazed surface off, but wear an N95 mask or hold your breath while sanding   .
Also, new drums don't typically come "turned" to a perfect circle inside the drum.  That will be done by the brake shop along with the shoes.  If you buy new drums and shoes that have not been turned and arced you can generally find a local brake shop that will for a nominal fee turn the drums and arc the shoes for you.