Community Forums

Ann-Marie · 03-19-2023, 04:29 PM

I love the simplicity of the NSA towbar system. Doesn't rely on 12 volts. It works great but I've had 3 problems.

1. One of the arms would not lock. After aggressive bitching NSA replaced it.

2. The braking system was too severe. Occasionally when braking the brake would go on and instead of just slowing the toad down, it would brake hard and pull the thrust off the towbar. That would release the brake and the inertia would then re-engage the brake causing a disconcerting oscillation.

I lowered the cable attachment on the brake pedal which was too high. By lowering it to behind the pad it was further from the radius and required more motion, reducing the brake effect. That improved it but didn't solve it.

Here is my latest solution, an extra hole in the arm, that should reduce the amplification by about 20%. If it needs more I can add another hole even lower. Going on a trip next week that will test it.

3. Because of the layout of the equipment on the Ford Fusion Hybrid toad, the brake cable access was about 10 inches offset from the center line. This meant that when turning left the brake cable was slack and would not brake and when turning right it was stretched and braked unnecessarily.

I solve the problem by attaching a piece of aluminum angle to the pivot bolt and passing the brake cable through a hole on it. Now it didn't matter what angle of turn the distance was always the same.

BOTH these should be incorporated by NSA!

MrMark52 · 03-19-2023, 08:53 PM

With all due respect -

For #2 - the force applied to the toad brake is proportional to the toad force against the internal load spring.
If the position of the cable connection to the lever arm is moved closer to the lever arm pivot point, the same result will happen only there will be less stroke available which would require a tighter adjustment of the pull cable. The cable being tighter will not allow for inconsistencies when making turns.

For #3 - NSA specifically states in their install instructions to center the pull loop in front of the vehicle as closely as possible. Doing so insures the proper slack length in the pull cable does not pull the toad brake when making turns.
Your offset bracket improves things somewhat, but now the lever pulls the cable, it also see’s an unintended lateral load which could result in a bent lever arm.

I’m not sure you clearly understand the physics and geometry behind how the system works.
And if everyone were having the issues you have encountered, I don’t think NSA would be in business very long.

Are you certain there isn’t something about how the Fusion’s braking system works that isn’t causing the issue? I know some EV’s use dynamic braking - could it be that much as hydraulic brakes work regardless of ignition or engine status - could energizing of the brake switch thru movement of the brake pedal be engaging dynamic braking, and now the NSA system and the Fusion braking system are fighting each other?

twinboat · 03-20-2023, 05:15 AM

Isn't the cable going to wear thru the aluminum angle ?

Ann-Marie · 03-20-2023, 06:10 AM

Quote:

Originally Posted by twinboat

Isn't the cable going to wear thru the aluminum angle ?

I would estimate that will happen around January 3045. The hole is rounded on the edges and the cable has a vinyl cover. No wear after a year.

Ann-Marie · 03-20-2023, 06:30 AM

Quote:

Originally Posted by MrMark52

With all due respect -

For #2 - the force applied to the toad brake is proportional to the toad force against the internal load spring.
If the position of the cable connection to the lever arm is moved closer to the lever arm pivot point, the same result will happen only there will be less stroke available which would require a tighter adjustment of the pull cable. The cable being tighter will not allow for inconsistencies when making turns.
WHAT? The cable has the same tightness as before, 2" slack per NSA. The purpose was to reduce stroke and the depth of motion of the brake pedal for a more gentle braking. There is no inconsistency when making turns, that is a design error corrected in #3.

For #3 - NSA specifically states in their install instructions to center the pull loop in front of the vehicle as closely as possible. Doing so insures the proper slack length in the pull cable does not pull the toad brake when making turns.
Your offset bracket improves things somewhat, but now the lever pulls the cable, it also see’s an unintended lateral load which could result in a bent lever arm.
WHAT? Now the cable tension is always directly in line with the lever arm motion no matter what amount of turning, how is a pull of about 10 pounds, directly in line with the arm going to bend it?
I’m not sure you clearly understand the physics and geometry behind how the system works. Its obvious you jumped in without comprehending the modification.
And if everyone were having the issues you have encountered, I don’t think NSA would be in business very long.

Are you certain there isn’t something about how the Fusion’s braking system works that isn’t causing the issue? I know some EV’s use dynamic braking - could it be that much as hydraulic brakes work regardless of ignition or engine status - could energizing of the brake switch thru movement of the brake pedal be engaging dynamic braking, and now the NSA system and the Fusion braking system are fighting each other?You may be correct here. Since it is a hybrid the braking system would not depend on having the engine running for vacuum or oil pressure. However other braking systems actually add a vacuum pump so that suggests you need a dynamic system?

Please see the responses in RED

wildtoad · 03-20-2023, 07:32 AM

What is the status of the Fusion when towing? The manual isn’t real clear in the recreational towing section. Keys in ignition at what position. Is the power ON in the car when towing? Are the power brakes active? The ready brake system is designed for power being OFF while towing. If power brakes are active you will get what you’re getting and no amount of tinkering will make them work properly.

MrMark52 · 03-20-2023, 08:25 AM

All you have done by drilling the additional hole closer to the pivot point in the lever arm is change the amount of slack that can be taken out of the cable before the brake engages.

Watch the following -

https://www.youtube.com/watch?v=G6sEJsrCh28

It is also possible that with your change and the cable being adjusted with the 2” droop, that if the NSA “bottoms out” under hard stop conditions, the TOAD brake may not fully apply (this putting additional load on your coach brake system).

10 pounds of cable pull? While I have not gotten a scale and measured how much pull it takes to engage the brakes on ours - I’m pretty certain it is more than 10 pounds, a lot more.
Don’t forget - the physics of sitting in the driver’s seat and pressing the brake pedal might seem like 10 pounds, but I’m certain it’s quite a bit more.

Systems that add a vacuum pump are not the NSA system. I just looked at the install of a SMI Brake system on a friends Jeep GC (hydraulic brakes) that he is pulling behind a DP (pneumatic brake). The vacuum pump assists the GC’s brake power cylinder in much the same way as a running engine does. I didn’t get into how it was controlled - whether it ran all the time or had a vacuum reservoir and pressure switch. But there was a vacuum operated slave cylinder that cable connected to the brake pedal arm much like the NSA system does.

The design of the NSA system doesn’t care if there is vacuum on the TOAD or not. If the inertia of the TOAD as applied against the internal spring exceeds what NSA has deemed indicates braking needs to be applied, it gets applied via compression of the internal spring, which then moves the lever arm, pulls the cable, which then pulls the brake pedal to apply a force of braking equal to the inertia being applied.

Your added hole just makes all the cable adjustments more critical.

bigb56 · 03-20-2023, 08:31 AM

I've seen a guide bracket on some older NSA Ready Brute systems but I guess they no longer supply them, just like they stopped supplying the bow shackle which makes connecting and disconnecting the sling cable harder. I called them about the bow shackle and they told me with 2 people I don't need it, just have the helper get in the toad and press the brake

bigb56 · 03-20-2023, 08:53 AM

So I called NSA out of curiosity and they said the guide I pictured above is a "stow strap" to secure the tow bar while in the stowed position on the older units and they had to cut a slot in it because it was in the path of the cable, so even though it does guide the cable that was not it's intended purpose. It is indeed called a "stow strap" on the schematic and it does show it latching the tow bar in the stowed position on the pdf manual: https://www.rvupgradestore.com/v/vsp...structions.pdf This would also explain why they no longer provide the small bow shackle (which they call "actuator arm clevis"), the new models use a pin at the pivot point to secure while stowed.

wildtoad · 03-20-2023, 10:04 AM

MrMark52, absolutely true. But am I wrong that if X pounds of pull from the Ready Brake cable is applied to a “dead” pedal versus a “live” pedal the results will be different. Just as if I press the “dead” pedal vs “live” pedal? If not, then I’d question the value of power brakes.

“The design of the NSA system doesn’t care if there is vacuum on the TOAD or not. If the inertia of the TOAD as applied against the internal spring exceeds what NSA has deemed indicates braking needs to be applied, it gets applied via compression of the internal spring, which then moves the lever arm, pulls the cable, which then pulls the brake pedal to apply a force of braking equal to the inertia being applied“

MrMark52 · 03-20-2023, 12:14 PM

Quote:

Originally Posted by wildtoad

MrMark52, absolutely true. But am I wrong that if X pounds of pull from the Ready Brake cable is applied to a “dead” pedal versus a “live” pedal the results will be different. Just as if I press the “dead” pedal vs “live” pedal? If not, then I’d question the value of power brakes.

“The design of the NSA system doesn’t care if there is vacuum on the TOAD or not. If the inertia of the TOAD as applied against the internal spring exceeds what NSA has deemed indicates braking needs to be applied, it gets applied via compression of the internal spring, which then moves the lever arm, pulls the cable, which then pulls the brake pedal to apply a force of braking equal to the inertia being applied“

The addition of “power” to a braking system does not increase the amount of force applied to the brakes - it only makes it easier to press the pedal to apply the brakes.

Another way to look at it is - you could make it just as easy to press the brake pedal of an unpowered brake system by doing nothing more than making the pedal shaft longer - but then you would have to put a hole in the floorboard for the pedal to reach thru and the operator to depress the brake pedal.

Assuming a power brake assist vacuum diaphragm of 8”, and taking advantage of engine vacuum at say, 15” - the power assist provides ~28#’s of the force needed to depress the brake pedal against the master cylinder.

twinboat · 03-20-2023, 12:57 PM

If the brakes apply easier with vacuum, then the car will slow with lighter pull on the cable.

The car slowing will lesson the push on the actuator , so with or without power assist, the car should stop the same.

MrMark52 · 03-20-2023, 01:11 PM

Quote:

Originally Posted by twinboat

If the brakes apply easier with vacuum, then the car will slow with lighter pull on the cable.

The car slowing will lesson the push on the actuator , so with or without power assist, the car should stop the same.

Right!

wildtoad · 03-21-2023, 07:49 AM

Quote:

Originally Posted by twinboat

If the brakes apply easier with vacuum, then the car will slow with lighter pull on the cable.

The car slowing will lesson the push on the actuator , so with or without power assist, the car should stop the same.

True. My thoughts, which admittedly may be faulty, is energized brakes would be easier to lock up the brakes, where they would not otherwise. Or perhaps apply brakes more often than necessary.

Always trying to learn.

Regardless, the Ready Brake works fine on my Wrangler.