Pop Up Brakes

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We all get into our vehicles every day and drive off without thinking about how the brakes are going to stop us when we need to.  Now that you have, or are thinking about getting a pop up brakes become more important.

When you vehicle was manufactured, it had brakes installed that will stop the vehicle loaded to it's maximum weight - plus a little extra.  Think about it, we are now going to hang an additional 1,500 pounds on the back end of our car.  What do you think is going to happen to the distance we will be able to stop in?  This is why some vehicle manufacturers add larger brakes to a tow package.  If you are buying a new tow vehicle ask if there is an option on larger brakes.

The "legal" need for brakes on a pop up is different for each and every state.  Some say any trailer weighing as little as 1,000 pounds must be equipped with auxiliary brakes while one only requires it on trailers 10,000 pounds!  Pop up manufacturers are beginning to realize the need for brakes even when not legally required.  Beginning in 2001, one manufacturer, Fleetwood Folding Trailers/Coleman equips ALL pop ups, no matter how small with brakes.

Trailer brakes come it two basic varieties, electric brakes and surge brakes.

A story that I think points out the need for brakes was recently posted on one of the web message boards; here goes:

Surge Brakes

Surge brakes are a hydraulic brake that is activated by the forward pressure of the trailer against the hitch as the tow vehicle begins to slow. They are often referred to as a less complicated system because you do not need special wiring between the tow vehicle and trailer or the installation on an in cab controller. They are actually a fairly good braking system, but with the simplicity comes a couple of drawbacks: 

1.They do not allow the driver to independently control the brakes from the drivers seat as electric brakes allow you to.

2. In most surge brake systems you must exit the vehicle and disable the brakes before you can back up.

With these two things in mind, they do actually work very well and have some advantages; they don't have as much to go wrong (less maintenance) and the wheels can be submerged in water (think boat trailer) without damaging the brakes. Surge brakes are "true" proportional brakes, the harder the tow vehicle stops, the more pressure is applied to the tongue and the brake's actuator thus causing the brakes to increase braking pressure.

  With all that said, I would NOT pull a pop up without brakes! With today's smaller vehicles trying to pull ever larger trailers brakes are a necessity (even if your state does not require them).  If they are an option on your trailer, buy them!

Electric Brakes

Now, if you read the section on surge brakes you now know that electric brakes are a little more complex, but not to worry.  Electric brakes as if you couldn't tell from the name uses electricity to activate the brakes. In an electric brake system there are parts installed in the tow vehicle, parts installed on the trailer and a connection between the two.

In the tow vehicle you have a brake controller.  This device sends a signal through the wires to the brakes on the trailer not only telling them when to activate, but also how forcefully to activate.  More on brake controllers below.  At both ends of the trailer axle(s) you will find the brake drums, with electrically activated shoes inside.  As the electrical voltage from the controller increases, magnets in the brakes force the shoes against the drums creating drag and slowing the trailer.

Electric Brake Controllers

Time Based Controllers

The original (they are still sold today) electric brake controllers were time based, meaning that when you stepped on the brake pedal, in a set amount of time the trailer brakes would go from no braking force to full braking force.  These controllers usually have a knob or wheel you turn to increase/decrease the time and an additional knob or wheel that you turn to increase/decrease the braking force.  The downside to time based controllers is that the do not sense the difference between slow controlled stopping and an emergency stop.  Once the "time delay" has passed the controller has the brakes at full force, whether you need it or not.  This makes for some jerky towing at times.

Inertial Controllers

The newer models are inertial controllers, meaning they constantly sense the inertia (forward motion) of the tow vehicle and only apply the amount of braking necessary for the current conditions.  In an emergency situation it senses the sudden deceleration and applies full braking, in a controlled situation it senses the slow deceleration and slowly applies the brakes

Both types of controllers have a manual activation lever on them to allow you to engage the trailer brakes independently of the tow vehicle brakes.  This may be needed in order to control a sway situation.

Break Away Switch

If you have brakes installed on your trailer, be sure you have an operational break away switch.  This device activates the trailer brakes should the trailer "break away" from the tow vehicle.  See the Break Away Switch page for more information.

Downhill Braking Techniques

Going down significant hills while towing a trailer is a very different kind of towing. Here are some things to know and do before you tow, and after you get to the top and you need to go down the other side.

The single biggest aspect of going down hill is getting rid of energy. A tow vehicle and trailer are near perfect mechanisms for turning potential energy (altitude) into kinetic energy (speed). What is important is having mechanisms for turning that kinetic energy into something else. The main thing it is changed into is heat. (Small amounts are changed into noise, and modest amounts into wind and turbulence, but those are beyond the control of most drivers.) The friction in brakes heats the drums or rotors. The friction in transmissions and engines also generates heat. As long as that heat does not become excessive, going down the hill is as safe as going up. But the problem is, that heat can become excessive!

Here are some things to do:

1) Educate yourself about the hills you will be negotiating. Hills are measured by grade and length. Grade is measured in percent, such as 4%. That means for every 100 feet you go forward, you will go down (or up) by 4 feet.

A 4% grade for two miles goes down as far as an 8% grade for one mile, but they are not the same. The 8% grade will heat braking components twice as fast as the 4% grade. There are grades in the east as high as 12% for short distances, and as high as 20% in the west. If I had to tow up or down a 20% grade for more than 1/8 of a mile, I would find a different route, period.

If you will be doing a lot of towing in the mountains, get one of the guides on mountain passes. R & R Publishing publishes two (Mountain Directory East and Mountain Directory West), Good Sam has one, and I believe AAA does as well. They can tell you in advance if there are steep grades on the road ahead. Sometimes they will tell you about other road conditions, such as location of runaway truck ramps, lack of guardrails or shoulders, sharp drop-offs, bad surfaces, narrow roadways, or when roads are in open rangeland, meaning there may be livestock on the road.

2) Make sure your trailer has adequate brakes. What does adequate mean? The answer is, it depends. If the trailer is relatively heavy, and your tow vehicle is relatively light, then the trailer brakes need to be very good indeed. On the other hand, if you have a very small trailer that you tow with a heavy duty pickup, adequate may mean no brakes at all. With our setup, the van is 1,000 lbs. per wheel and the trailer is 1,600 lbs. per wheel, so I clearly need top quality brakes on the trailer.

Some states require brakes on all trailers over 1,000 lbs. Others draw the line at 1,500 lbs, 2,000 lbs, and some at 3,000 lbs. One state (Massachusetts) only requires brakes on trailers over 10,000 lbs! But what is legal is not necessarily what is safe.

Tow vehicle manufacturers also have limits beyond which you must have brakes. These limits are often fairly low (as low as 1,500-2,000 lbs.) and should not be exceeded. This is the weight at which the manufacturer is saying their brakes are not good enough.

3) Make sure your trailer and tow vehicle brakes are in good condition. Drums and discs should meet the necessary standards. Pads and shoes should not be excessively worn or glazed. Fluid levels should be at their ideal level. If you have surge brakes, don't forget the fluid level on the trailer.

4) Make sure brakes are in proper adjustment. All passenger vehicle (including pickup truck) front brakes adjust continuously as you drive. Many, but not all, passenger vehicle rear brakes do as well. For those that do not, they adjust under special circumstances.

The most common techniques I have seen for adjusting the rear brakes (for vehicles that do not adjust continuously) are firm braking while backing up, and applying the parking brake. Find out if your vehicle uses one of these techniques, and do it every time you hook up your trailer.

With electric brakes, the trailer brake or axle manufacturer has a recommended adjustment interval. Make sure you know the interval and that the necessary mechanical adjustments are made.

Make sure your brake controller is adjusted and working properly. It is a good idea to test it as soon as you hit the road every time you tow. Test it again after 5-10 miles, because electric brakes become more efficient after warming slightly.

5) Reduce cargo or trailer weight. The amount of energy that needs to be dissipated is directly proportional to the weight of the vehicles being stopped. If you can reduce that weight (by leaving the canoe behind, or even better, leaving Aunt Bertha and her luggage behind), that reduces the load on the brakes. If you can take 300 lbs of gear or passengers out of the tow vehicle and trailer, that has the same impact as reducing the trailer weight by 12%.

Are you really going to use all five bicycles and both canoes high in the mountains? Do you really need three 18" Dutch ovens and four 20" cast iron frying pans? Most of us haul a lot of stuff we never use. If you are going to the mountains, consider what you can leave behind. BTW, this will improve performance going up the hill in the first place as well.

6) You've come to the top of the hill, and there is a brake check area. Use it! If the hill is steep enough to need a brake check area, it is important to stop. Particularly if it's been a long climb up the hill, you need to stop and let your transmission cool. It's just had a workout getting up the hill, and it's going to get another going down. Give it 10 minutes or so (with the engine idling) to cool off. At the same time, make sure the trailer brakes are working.

7) Downshift. The saying used to be "go down in the same gear you went up in" but with today's high-rev engines, that is no longer adequate. Go down one gear lower than you went up. Be alert to the fact that the downhill side may be steeper than the uphill side and so you may need to downshift further. Downshifting puts some of the braking energy on the transmission and engine, which have systems that are designed to deal with the heat. Your engine will not overheat because you are using engine braking, but your transmission can, which is a good reason for an auxiliary transmission cooler.

8) Don't ride the brakes. Allow the vehicle to coast for short periods to gain 5-10 MPH, then brake firmly to slow by 5-10 MPH. Nearly all vehicles today do very little or no braking with the rear axle brakes unless you brake firmly. By braking firmly, you shift some of the heat off the front brakes onto the rear brakes.

Braking firmly also shifts more of the braking on to the trailer brakes. Trailer brakes (especially surge brakes, but it's also true of electrics) have a threshold below which they won't do much of anything. By braking firmly, you force some of that stopping energy (heat) onto the trailer brakes.

Another benefit of intermittent, firm braking is that you will be more aware of when the brakes start to fade. Brake fade is a warning sign of a very dangerous overheating condition. More about that later.

The benefit of coasting is that it allows the engine and transmission to absorb some of the energy (as they rev up). There is a limit to this. You don't want to redline your engine or transmission, and some automatic transmissions will up shift if they get far outside their normal operating range. Also, once the engine RPM's stop increasing, the amount of braking being done by the engine is decreased as well. This is why you need to use both the brakes and the engine.

Basically, use both the brakes and the engine/transmission to control your speed.

9) Slow down. Braking on a long downhill generates a lot of heat. It is important for the heat to dissipate as fast as it is generated. Since there is no easy way to speed up the cooling of the brake components, it is necessary to slow down the heating of the components. After doing all of the things listed above, there are only two ways to slow heat buildup. You have to either slow down or stop. If you come to a scenic pull-off, it won't do anyone any harm for you to stop for five to ten minutes to let things cool off.

10) Be alert for signs of brakes overheating. Overheating brakes can:
* fade to nothing
* suddenly fail
* cause tires to burst and/or catch fire
* cause other suspension components to overheat
* seize up
* warp rotors or drums
* a few other things I can't remember at the moment...all of them bad.

Signs of brake overheating are:
* A loss in brake effectiveness
* A "hot" or "metallic" odor
* Smoke coming from the wheels or behind the trailer or tow vehicle
* The brake light coming on
* Sudden "gabbiness" to the brakes
* Increased brake pedal travel
* Decreased brake pedal travel
* An unusual "soft" or "spongy" feeling to the brake pedal
* An unusual "hardness" or "stiffness" to the brake pedal

Whenever any of these things occur, you are driving into a dangerous situation that will only get worse until either: 1) you stop 2) you come to flat or uphill roadway or 3) you can't stop or can't stop in time. Since #3 is not acceptable, and you have no control over #2, stop as soon as possible when ever you get signs of brake fade.

If you can't find a place to stop, stop in the road. Just make sure approaching traffic has something to warn them of your presence. Also, be aware that at this point, your brakes could be hot enough to start fires, so that is something to watch out for if you pull off into tall, dry grass, etc.

11) OK, you pushed your luck, and now you are in trouble. The brakes won't stop the rig, and appear to be gone. Now what? Do the first four of these as fast as you can:
* Pump the brakes. If the brake fluid has boiled or is leaking, this may give you some temporary brakes.
* If possible, downshift more. A damaged engine, transmission, or clutch is better than a high speed crash.
* Apply the emergency brake as hard as possible. There might be something there that will help you stop. The emergency brakes uses cables, so is not affected by the loss of brake fluid. Be aware, though, that on it's best day, the emergency brake will give you about 1/4 of what the regular brakes will. Even if it works perfectly, that's not much.
* Apply the trailer brakes manually. Move the controller's lever all the way over and hold it there. Be aware that this, like the emergency brakes, isn't much, but when you've lost it, a little is better than nothing.

It shouldn't take more than five seconds to do those. Next, try:

* Use that runaway truck ramp. Although they are designed for big rigs, I believe they would work for a pickup hauling a popup. I would use one, but expect some cosmetic damage to the trailer or van as a result.
* Turn uphill. This is very rarely an option, but you can't coast uphill very far, so that will stop you.
* Sideswipe something. This is an extreme last resort move to be used only in life-or death situations. Sideswiping a guardrail, phone pole, or parked vehicle is a move that could still kill, but is far less dangerous than slamming into the guardrail, phone pole, or parked car. You could loose all control, particularly if the air bags go off. You could end up in the face of oncoming traffic. You could injure or kill people on the side of the road. Don't get into that situation to begin with.

My thanks to "Austin_Boston" on the Pop-Up-Times message boards for the content on downhill braking as well as proofreading for this page.

Note Photos on this page Copyright © Tekonsha