I have a triple axle trailer towing a 38 foot Cigarette. I installed electric over hydraulic drum brakes myself. When I hit the brakes, there is about a 3-4 second delay before they kick in. Any suggestions on what I did wrong? Mabye I did not bleed the brakes in the correct order.

If I had to guess, I would say air in the line, just like you were thinking. I bled them from front to back at each caliper going in order. Mine had a delay when I change brake fluid. Fixed the problem. However mine are not drums, they are discs.

What controller?

I purchased the Tekonsha P3 Electric Brake Controller. When it engages, I can really stop fast. It's that delay which scares me.

I thought you are suppose to go from back to front?

If the delay is in the time before the pump kicks on, I don't see air in the lines being the issue, but in the controller?

The pump comes on as soon as I hit the brake. Maybe I should bleed the brakes front to back, instead of back to front.

Is there a delay built into the box ??

Are you sure the shoes are adjusted properly? Maybe they are not out close enough to the drum and it takes a second or two for them to make contact???? I would also re-bleed the system and be sure you have good clean fluid at all the wheel cylinders. I have always bled brakes starting from the furthest point.

I don't think it makes a difference in front to back or back to front but the adjustment will absolutely cause a delay. I bleed mine both ways each time anyway since I'm not sure. Adjust out until I can't spin the wheel then back off 10 clicks.