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
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:
|...can't you smell that
Ooo-oooh, that smell,
of a time-based control-lerrrrrrrr?"
(apologies to Lynyrd Skynyrd )
Was driving through the usual mountainous areas of my home county
yesterday morning, on a long and curvy downhill run. Then the first
wafts of a pungent odor reach my delicate nasal membranes: the
stench of burning brakes.
"Hmmm, must be another logging truck with a bad set of air
brakes up ahead."
I proceed down the grade, keeping a sharp eye out for whatever is
surely in front of me, creeping slowly down the mountain as it
leaves a trail of smoking brake material. This goes on for another
mile and a half, until finally I catch a glimpse of whatever is
ahead of me. Far in the distance, coming into view around one of the
many corners the road makes as it traverses the convoluted terrain,
is a mini-van pulling a pop-up.
"Ah-Ha! So that's it! Hmmm... I wonder if they belong to
I catch up to the smoking trailer near the bottom of the hill, and
notice the driver's braking pattern: the same way most folks use
them, gently riding the brakes for short periods of time as he
carefully pilots his rig down the mountain. No sudden braking
maneuvers or careless speeding from this guy. A careful driver, to
be sure. Unfortunately, the driver is blissfully unaware that he is
frying his trailer brakes. I blink my lights and tap the horn,
getting his attention. Good, I think to myself as he pulls over to
the side of the road and slowly comes to a halt, this guy isn't one
of those who ignores other drivers. I pull up next to him, and lean
out of my truck.
"Excuse me, but I thought you should know. You're heating up
your trailer brakes really bad. You wouldn't happen to have a Draw-Tite
brake controller in your van, would you?"
A look of astonishment. "Why... yes, we do. How'd you know
What follows in the next few minutes is a crash course on different
brake controllers and what to expect of them. Turns out their pop-up
dealer sold them the Activator-II controller, saying it would work
Gee, where have we heard THAT story before???
The gentleman and his wife were off on a trip to the coast. Seemed
like nice folks, exactly the kind you want to have join your group
at a club rally. He had no clue about the dangers of a time-based
brake controller in real-world driving. (That's certainly not his
fault, as none of us did before we learned about inertial
controllers, right?) Pity his dealer couldn't have been more
interested in his customer's safety than making a quick buck. A
little further down the road, and his trailer brakes would have been
history. Add an emergency situation, and his mini-van would never
have been able to stop in a safe distance.
I gave them some quick info on PUT, scribbled on the back of one of
his business cards. Unfortunately, I was behind schedule, and
couldn't chat any longer. I wished them a nice weekend, and hope
they check out PUT when they get home.
"Hey", he asks as I begin to pull away, "How'd you
know we were heating up our brakes?"
Not wanting to worry him too much about the smoke that has stopped
rising from the now-cooling trailer brakes, and since the rest of
his trip was on relatively flat roads, I could only say:
"By that smell, sir, by that smell."
Thanks to Dave "Ab Diver" for this great story!
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!
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
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
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
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
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
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
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
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
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
* An unusual "hardness" or "stiffness" to the brake
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
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