Brake delay

[hlh1]

Today I was adjusting and checking out the TT brake system. I would spin each wheel and have my wife apply the truck brakes to make sure the electric trailer brakes operated correctly. Each TT wheel and brake would stop spinning when the truck brakes were applied but with a 5 second delay. Is this normal? I've tested the TT brakes while moving by just applying the trailer brakes manually, from the truck, and they immediately work lockup in gravel.

[JRTJH]

I'm not sure what brand of brake controller you are using.

If it's a Ford OEM integrated brake controller, then it's a "smart controller" and knows if the truck is moving, how fast it's moving, how hard the truck is decelerating and if there's any "lateral G forces" from turning a corner, slipping on the pavement, etc. With the truck "sitting still" the braking effort (voltage) sent to the trailer brakes is not going to be the same as the power sent to the brakes in normal driving/towing and different still from the "panic stop" power applied to the trailer through the 7 pin connection.

That 5 second delay may be "truck computer interface induced" rather than a problem with the trailer brakes.

So, what kind of brake controller are you using?

[dutchmensport]

Agree with JRTJH, except mine is an Integrated Brake Control on my Chevy. Works the same way as JRTJH's. I don't know if there is "delay" on mine, but the truck and trailer brake together. One does not over power the other. Sometimes I do wish the trailer would break first, or at least a bit stronger at first. But it doesn't. I've learned to adapt.

[hlh1]

It has the brake controller, OEM, that came with the F150 towing package. I was thinking that there might be some brake "logic" going on but I wasnt sure. I towed the setup for about 5000 miles last year and had no issues, but I'd never "hand spin tested" the TT brakes before.

[chuckster57]

Originally Posted by hlh1

It has the brake controller, OEM, that came with the F150 towing package. I was thinking that there might be some brake "logic" going on but I wasnt sure. I towed the setup for about 5000 miles last year and had no issues, but I'd never "hand spin tested" the TT brakes before.

If you’re simply testing to verify the brakes work, just pull the break-away pin. Make sure you put it back in. That way you’re testing the brakes, break away and the pressure needed to pull the pin all at the same time.

[sourdough]

Originally Posted by chuckster57

If you’re simply testing to verify the brakes work, just pull the break-away pin. Make sure you put it back in. That way you’re testing the brakes, break away and the pressure needed to pull the pin all at the same time.

^^^^Be sure to heed Chuck's advice above. Those brakes will drain the battery in short order. My dealer found that out after they forgot the pin, killed my batteries and had to buy me 2 new ones.

[hlh1]

Next time I will try just pulling the pin, and yes, reinstalling it.

[Customer1]

A brief delay is normal, first the magnet is energized and attracted to the drum. After the magnet connects to the drum it moves an arm which then causes the shoes to spread out and contact the drum.

[NH_Bulldog]

As John said previously, the built in brake controller is “smart”. It does not apply full braking under 10 mph and at speeds over that it applies brakes proportionate to your speed, pressure on the brake pedal and rate of deceleration. Chuck and Danny have it right; pull the breakaway pin and check your brakes that way.

Think of the delay in terms of most any vehicle, motorcycle or bicycle; the majority of braking force is applied to the front wheels (60-70%). This is why front wheels tend to exhibit more brake dust than rear wheels. When you are towing a trailer, you want the truck to be braking before the trailer, so there is an intended delay when you press the brakes to allow the truck brakes to engage before the trailer brakes kick in.