Air Brake Units For RV’s With Full Air Brakes
There are several braking units that
will work with coach air brakes.
This article explains Blue Ox’s BrakeSafe
and Roadmaster BrakeMaster units.
These systems are quite simple and work
very well, with the braking unit operating in tandem with the coach brakes.
The two are very similar.
An air cylinder is used inside the
towed vehicle to push the brake pedal.
The cylinder mounts to the floor or
seat by a bracket and quick connecting pin.
In my opinion Roadmaster has an
advantage here since they now have brackets available to bolt directly
on
the driver’s seat for some vehicles. (With a seat bracket, it is not
necessary to drill holes in the floor).
A rod attaches to the brake pedal
using a spring loaded clasp.
An air line is routed from the front of the
towed vehicle along the under hood area, then inside the vehicle
going
through the firewall. A connector and bracket are provided to mount at the
front of the towed vehicle
close to the tail light wiring connector. The
line attaches to the air cylinder by an air coupling.
It should be routed
along the sill plate to an area under the seat where it can be stored out of
site when not in use.
On the coach end, the air supply will
be teed into the air brakes. Be certain the coach can handle this system.
I
recommend checking with the manufacturer of the coach to be sure they will
allow tapping into the air brake system.
If allowed, hook into the air
brakes near the rear of the coach close to one of the actuators at the
relay.
The actuators are the air bellows that activate the braking
mechanism.
I find in most applications there is a relay close by that has a
plug in it.
Be sure the wear some type of hearing protection for the next
step.
Simply remove the plug then have a helper activate the brake by
pressing the brake pedal.
Be sure the air flow comes out of the fitting
where the plug was removed only when the brake pedal is activated.
Use one
of the adapters provided to connect an air line to the correct fitting.
In
some cases you may need to find the correct style or size fitting from a
parts supplier.
Route the air line away from any moving parts to the rear of
the RV where a bracket and coupler can be mounted.
A coiled air hose is
provided to make the connections between vehicles.
There is an optional indicator light
provided to mount inside the RV.
The light is activated from the towed
vehicle’s brake light switch when the brake is applied.
A single wire is
provided with the kit and will need to be routed from the brake light switch
to the front of the towed vehicle.
You will need to install a brake light
relay kit. This kit will eliminate two problems.
It will disable the towed
vehicle from lighting the brake lights thus eliminating a battery run down
condition.
It will also keep the braking unit from overriding the turn
signals while towing.
The relay kit is available from Roadmaster and
included with Blue Ox’s BrakeMaster.
There is a separate wire with quick
connectors to attach between the towed vehicle and RV.
A wire will need to
be routed from the rear of the RV all the way to the front, then inside to
the dash area.
A hole can be drilled to install the light.
A breakaway unit is separate for both
braking units and is required by law in some areas.
Unfortunately, the
breakaway makes a very simple and easy to install braking unit difficult and
complicated.
In my experience the breakaways take about as much time to
install as the rest of the system.
The breakaway uses a separate air storage
cylinder to supply air to the braking unit in case of a separation from the
RV.
There is the typical 2 wire breakaway electrical switch to mount at the
front of the towed vehicle.
This switch will be linked to the RV with a
small lanyard cable.
You will need to find a location under hood for a
rather large air supply tank.
The tank will tee into the air supply line
feeding the inside cylinder.
There is a solenoid assembly that activates the
breakaway from the breakaway switch.
There is tee to feed the inside
cylinder from the solenoid.
This type of air braking systems is
what I recommend for RV’s with full air brakes
as long as the manufacturer
of the RV permits tapping into the air brakes.
They work proportionately
from the RV’s brakes without electronics which makes them very accurate,
reliable, and dependable.
Preparing to tow is quick and easy. The only
problems I have seen with this system have been with the breakaway.
The air
operated breakaway system is reliable with the exception of the breakaway
switch which I explained in a previous article.
This article is by Mike Wilson,
RVDA Certified Master RV Tech. and may not be reproduced.
All RV Tip articles are provided for information only. Articles
are based on the best professional judgment and experienced opinion of
the writer.
Wilson RV nor the author accept any liability as a result of provided
information.
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would like to ask Mike a question about air brakes, please visit our new RV
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