MB ML350 into a Toad

[Dennis]

Okay I promised I would post my experience with the NSA surge brake. On my first real outting of 50 miles, I took extra care to go slow and watch to make sure the toad wheels were turning without effort. I made the cable loose not only because I was causious, but because I am only interested in heavy braking situations not light stop and go braking. The tow went excellent HOWEVER, when I got to my destination apparently the cable was too tight and with ABS brakes the wheels kept turning with the brakes applied and I burned up all 4 brakes; they had been red hot. $1,800 later I had all new brakes and on the return trip all went well. I called Todd at NSA and he could not figure out what went wrong; obviously the cable was too tight. Odd thing was that when I stopped the Coach at my destination the cable was tight, but the brake peddle was in the full up position; brake lights were not on. Which tells me that when the toad surged forward on the trip even a little it was applying too much brake. BTW, I did not forget to wait until the tow bar fully extended before adjusting the cable. Expensive lesson! I thought a better way to have set the right length of cable probably would have been to make the cable tight, but not tighten the cable clamps so that as I drove the Coach forward they would slip the cable to the full brake position (length), then I could adjust the two or three inches Todd suggests.

[bubblerboy64]

Dennis, Interesting timing on your post. I've had a similar situation with my application with my Honda Fit. No significant damage to the car but something is happening with this system which is not as it should be. I would love to understand the variables here so I'll work at it from my end and lets keep on Night Shift Auto on this stuff.

Here is one thing we know for certain, once that cable is adjusted correctly it doesn't get shorter so how do the brakes get applied to the point that they are causing problems? The only variable other then the cable on the towing system is the spring in the tow bar which should be releasing to take the pressure off of the cable. There is nothing else to go either right or wrong in that loop.

One of the questions I have had is, is there something in the car which is not releasing once the brake petal is pulled tight. I will tell you that one time while driving the toad I had the brake get tight and not want to release. I pulled over looked under the hood to see it there was some obvious problem and could not find a thing. I got inside the car and fooled around with the brake petal and it seemed to release. I thought perhaps the bracket which attaches the cable to the petal got caught on the floor mats but for the life of me I couldn't think that would be sufficient to hold the petal down with enough force to noticeably slow the car. So I was never able to diagnose that situation which I think HAS to be related to the car getting bound up behind the coach. I even thought that perhaps the cable got twisted up inside the sheath up I've found no evidence of that. It's a mystery to me at this time.

My car is so light that I feel I don't need the car to be stopping by the car brakes but I would like the system working and especially I would like the cars brake lights to activate with the coach system.

I am going to talk to NSA and see if I can come up with some answers. This should work and I am at this point both somewhat disappointed and confused. None of these braking systems are without potential trouble this one logically seemed the simplest to me.

Keep me informed, and I'll do the same. By the way, if you adjust the cable with two to three inches of play in it will it provide any braking at all?

[bubblerboy64]

Just got off the phone with NSA and here is what Todd told me. He thinks in my application it's possible the cable has become slightly frayed in the sheath and not allowing the necessary movement to release fully after being applied. That's a possibility I'll have to check. I believe as well that my system was and has been adjusted just a little too tightly. So I will go back to zero and rework the adjustments staying a little on the loose end of it. He also suggest a bungee cord to the brake petal to provide some force counter to the cable to aid the brake release. This seems like a belts and suspenders approach which works for me. This kind of stuff drives me a little nuts because the lessons are costly. You read the directions, feel that you fully understand them and still have problems because there almost always is something either not covered or slightly different one application to the next. Todd did suggest the light system be installed to indicate the toad breaks are applied but I don't believe that would have made one lick of difference with the problems I have had. I am not going to fight the fight to run a line from the back to front of my coach. Been there and none that.

[Dennis]

John, In my case I DID have a bungie securely attached to the brake peddle and firmly anchored under my seat. The mystery part to me was that when the Coach was stopped, flat and level following the 50 mile tow, the brake peddle was in the full/full up position. Yes the cable was tight but not tight enouch to activate the brake or the brake lights. The only explanation that seems to make sense to me is that ANY forward (surge) motion of the Toad activated the brakes so that when I slowed down the brakes must have been activated to a point where even though the Coach continued forward the Toad brake was still activated. I was on the highway duing 55 MPH for most of the 50 mile trip. I can tell you that just looking at the brakes they must have been red hot because the metal was white from heat and the wheels were covered in brake dust. When we popped the wheels everything was melted, yet the tires were perfect indicating that the ABS kept them from locking. I left at least 2 inches of play in that cable before I left which is what Todd suggested. He asked me too about the red light, which I did not install and I am not certain it would have helped; perhaps it would have indicated that while the Coach was moving forward the brakes were still on??? I figure that if you set the cable at the approximate length and NOT tighten the clamps then drive forward and stop a few times this should pull the cable to the maximum length at full surge brake activation (when the NSA brake lever is in the full up position), then you can shorten the cable an inch or two from that to get to a point where the brake peddle will activate the Toad brakes.

Dennis

[Dennis]

John, here a PS to my message. At Todds suggestion I started my car and had my wife step on the brake peddle to make sure the cable was not binding (that the end loop of the cable in the front of my car was going in an out as she pumped the brake and it was); no binding in the cable. The brake-away cable which has plenty of slack was and is purfect.

[Dennis]

John, in re-reading your posts I think you might have hit on one possible cause, that the NSA brake system lever possibly did not release the cable tension as it should have i.e. got stuck in the up position. The system was brand new, sometimes mechanically moving parts get stuck until they are exercised a few times.

Dennis

[bubblerboy64]

Dennis, I think while the system is simple it has to be finely tuned to work as designed. Unfortunately the fine tuning has been costly especially for you. I think your situation was simply that the cable was just a hair too tight, just enough to activate the brakes before it should have. Once the brakes get hot they swell and that is what caused your major problem. If the cable had been a little shorter (therefore tighter) it would have activated the ABS which would have pulsed the brakes and you would have felt that in the coach. So you were at that critical point. Had the cable been looser no problem, tighter and you would have locked the brakes tight enough to lock the wheels activating the ABS. It then would have been immediately obvious there was a problem. When this happened to me the Fit was hopping as I came to a stop because the ABS was doing it's thing when the tires stopped turning. Do you agree with my thinking on this?

In my case, not certain what caused the binding when driving the car unattached to the coach but I need to see if I can figure that out. Could be a frayed cable. Todd suggested checking the movement of the cable in and out of the nylon bushing at the front of the car with someone applying the brakes to make certain the cable is releasing. I think I know what happened when the car was attached to the coach. I believe the cable was either too short or it was kinked or rapped around the lever resulting in a too short situation. Interestingly enough a friend was driving behind me in his bus and told me on the CB that the toad brake lights were coming on before the bus. This was happening going down hills which should have been a clue that the cable was too tight. I wrongly assumed that the lights were being activated and not the actual braking system. So I believe it would be a good idea to have some one follow and see what is happening especially since we don't have the monitoring system After driving awhile I believe like in your situation the brakes got hot and then the fun began.

I am still not completely certain I have this all figured out but I am going to error on the loose side of the cable adjustment rather then the tight and I believe I will be OK. I think what I will do is set up the tow bar with the car attached to the bus and push the car forward as far as it will go to depress that spring in the system lock the emergency brake in the toad and then adjust the cable to that point so that it "just slightly" activates the brake petal. This should activate the brake lights which is really all I am concerned about.

If you come up with any pointers or new information let me know. If running the indicator light wasn't such a pain I think it would be a good thing. I'll take my chances without it.

[Dennis]

John,

I am not sure I would have felt it skipping; the Coach is so heavy I certainly did not feel the braking of the Toad.

I asked Todd about a wireless brake signal light which he does sell, but he discouraged me saying that with a diesel pusher it sometimes does not work; engine interfers with the signal.

My neighbor who is a professional car mechanic and a good one said he will work with me on setting the cable including using a heat seeking gun to measure if the brakes are getting hot.

I tried to depress the spring when I first set up the toad, but it did not pop up and I did not want to force the issue. I will try again because I do think this would be a good way to set the cable length.

It may take me a few weeks to get the neighbor and my time lined up, but I will keep you informed. Please let me know how much effort you had to use to get the brake lever to pop up.

Thanks,

Dennis