Surge Brakes In Mountains?

[BretWayne]

I have towed with a tow bar in the past but changed to a car that could not be towed 4 down. So I bought a Car Caddy dolly with surge brakes. I have pulled it about 5,000 miles and really like it. However I just got back from a trip to Colorado and had a little problem in the mountians. I could not keep the brakes cool on the dolly. (Because when the dolly is pushing the motorhome "you can't just turn off the brakes"). No problems at with the motorhome, I have an engine brake so I hardly touched the air brakes. Any ideas (Other than changing it to electric brakes) ?

Bret

[desertdeals69]

You might try a stronger spring in the surge controller. It will then take more pressure to activate the brakes. It is proportional.

[curtwpk]

I live in the Colorado mountains so this is an important topic.

The conventional wisdom here is that "surge brakes don't work in the mountains".

I have looked into the idea of a stronger spring in the actuator - as suggested by desertdeals. I can't find any manufacturer that says that is even possible. You would certainly be on your own and the spring rating would be a toss of the dice.

I have thought of another solution that I am considering trying. This assumes that your actuator has a reversing solenoid switch that can lock out the brakes when backing, and assuming it is the type that works with backflow to the master cylinder.

One could wire a control for the solenoid that allows manual control in addition to the backup light control. Then when using engine braking on long hills just turn the trailer brakes off (locked out). You would need to be careful to remember to unlock them again and so this has its dangers.

Or... you could wire it so that the brakes can be manually locked out .BUT. they would be unlocked again if the tow vehicle brake lights come on. So on long hills, you lock out the brakes but if you hit the tow vehicle brakes, then the trailer brakes would be re-enabled. (over ride the manual lockout). This would be simple to wire.

In fact, with this solution, you could wire it up so the brakes are always locked out except when the tow vehicle brakes are applied. In other words, engine braking would not cause the trailer brakes to work at all.

The one thing I don't know - how do the trailer brakes behave when locked out and being towed forward ? Does the actuator bang back and forth loosely ? The lock out is designed for backing up - not forward travel.

[dickandlois]

Hi Curt, Welcome to FMCA,

Think safety first.

When you have to remember to turn things off and on manually, things can get dicey.

Modifying things can get into some major wiring and plumbing issues.

Having looked into the spring option has in a way pointed out the problem(s) of matching up an item to meet the required outcome.

Could you post your Coach Make, Model and Year. for the group. Unknown whether you have a Gas or Diesel powered chassis.

You might look at the Roadmaster Break Away Emergency Braking System 8600 as a solution or something like it.

This system is proportional when the brakes are applied and is off when you are using the engine brake or engine compression.

One needs to know that the system being used would not be voided by their insurer when or if modified. That could be a big issue should it come up a some point.

That is why using a certified system is important.

I would look at all the options and make a few phone calls, explaining your brake over heating and see what feedback you get. Look things over then you can make a better choice.

Rich.

[curtwpk]

When you have to remember to turn things off and on manually, things can get dicey.

Good points all, Rich.

I did some more head scratching on this idea and have concluded that using the lockout to prevent braking when using only engine braking has merit BUT I lean to making it "automatic" so one does not have to remember to turn the lockout on and off manually.

That seems to be fairly easy to do by hooking it up so that the surge brakes are locked out (using solenoid) except when the tow vehicle is braking. IE when the brake lights are on. As a fail safe, I would do it so that if there is no electric power at all, the surge brakes work in the normal way.

It seems that the only thing needed to do this is two reversing solenoids. One the closing type and one the recirculating type. Both are standard accessories for surge actuators.

-curt

2003 Safari Trek gas.

[desertdeals69]

Just keep in mind that any time you modify anything you become legally responsible if something should go wrong. Increasing the spring pressure would increase the force needed to apply the brakes but would not be re-engineering the system.

[hermanmullins]

Boat trailer have had surge brake lock outs for year. How ever they are attached to the back up lights. So when you want to back up the trailer, the power from the B/U light activates a solenoid that shuts off the flow of brake fluid to the wheels. I had problems with the electrical on my Jake Brake due to a bad connection. What would be nice, would be that M & G Engineering or Airforce 1 would engineer a air brake cylinder for trailers and tow dollies.

Herman

[wayne77590]

Be wary of hooking up anything to the brake light. Some exhaust brakes turn on the brake ligths when activated. My MH does.

[hermanmullins]

Wayne,

I under stand, what I was referring to is how the surge brake works on boat trailers. It is not hooked into the brake light, it is hooked up to the back up lights.

Herman

[BretWayne]

Thanks for all the input and sorry I have not responded until now.

The "Back up" solenoid lock out seems to be the most practical answer. I think setting it up as a manual lock out with a dashboard switch is the direction I will try. Buy doing this in the event of a break away the master cylinder would still lock due to the power being disconnected. I'm afraid that changing the spring tension would drastically reduce the braking ability when needed. As I stated in my original post I have no problems other than the long mountain grades which are a very small percent of my driving. And I am with you all the way Herman an Air Brake cylinder would solve a lot of problems!

Again thanks all for your input. That's why I just love this forum, I can get ideas from people that have a tremendous amount of knowledge that can't be found in books!

Bret

[curtwpk]

Bret,

I am in the process of hooking mine up like this:

1---Tail Light hooked to relay so that solenoid disables surge brakes when the tail lights are on..

2---Brake Light hooked to relay so that it over rides the tail light and enables normal surge braking. Brake lights on --- Surge brakes enabled.

So....

a-- When tail lights are off, surge operates normally.

b-- When tail lights are on (in the mountains) surge brakes are disabled EXCEPT when the tow vehicle brakes are are applied.

c-- IF there is no power at all - the system reverts to normal surge braking. (fail safe).

Bottom line... this allows me to disable the surge brakes when there is only engine braking that would cause the surge brakes to over heat. IF the brakes are applied, the surge are automatically enabled.

[desertdeals69]

I just returned from a 2300 mile trip to Kansas. Used my tow dolly for the first time in 15 years, to tow my Prius. My surge brake master cylinder was bad so rather than repair it I installed a air over hydraulic master cylinder so now my tow dolly brakes are activated by the air brakes on the motorhome.

[BretWayne]

Wow both good ideas. I have never seen an air over hydraulic master cylinder but I will be looking at this for an option.

[desertdeals69]

They were used on a Spartan chassis in the 90's. Four wheel disc brakes with air. When I changed the metal springs to air springs and went to air brakes I wound up with two of these master cylinders which are air activated.