Anti-lock brakes use microprocessor technology to sense when the wheels are about to lock up under braking and then con-
trols the brake pressure and timing to prevent it. Each wheel must be controlled independently, although only one axle of a multi-
axle configuration needs to be equipped with sensors. An exciter ring (sometimes referred to as a tone ring) is installed on the
inside of the hub. A sensor
reads
the level of magnetism present as the teeth of the exciter ring pass it. Since they don’t touch,
there is no wear or friction between them. The sensors provide wheel speed information to the Electronic Control Unit (the ECU
or system brain). Input from the sensors is used to determine if a wheel is about to lock during braking. If so, the system can re-
lease and apply the brake up to six times per second through the modulator valve.
The system is powered by the stoplight circuit. This allows any of your trucks currently equipped to pull trailers to be
used with a Sauber ABS equipped trailer. The system is off while the brakes are off and powers on and checks itself when the
brakes are applied. It is so fast that it can test itself sixty times before air from the tow vehicle gets to the trailer brake valves. A
warning light is provided on the trailer side and will illuminate if any component is not functioning. The system will continue to
have normal brakes until the problem is resolved. Although there are no batteries in the system, the electronic control unit (ECU)
has a special microprocessor that can remember up to ninety-nine problems and keep them stored until they’re fixed. A number
displayed on the hand held display unit (DDU) identifies one of sixty-three fault codes - providing accurate and quick
troubleshooting. This unit is available from Sauber Mfg. Co. and should be kept at each garage location expecting to service
ABS brakes. All cables are sealed, weatherproof and polarized to provide high reliability and mistake-free serviceability.
Air Over Hydraulic Brake Systems
Air over hydraulic systems have a built-in valve to allow application of the hydraulic trailer brakes in the event of a break-
away. The energy for this operation is stored in the air tank of the system. Therefore, once the air is expended, braking power is
released unless equipped with a spring brake mechanism.
Hydraulic Brake Systems
Straight hydraulic systems are equipped with a surge-actuated braking system. Pressure exerted on the towing eye is
transferred to the axle brake hydraulic cylinders. The greater the braking inertia, the more pressure is applied to the brakes. An
over-center actuator provides breakaway protection.
•
Proper Tongue Weight is established
It is critical to have a portion of the trailer load carried by the tow vehicle. The trailer tongue should always exert a downward
force on the hitch. Proper tongue weight is essential to good trailer tracking and safe operation. If too little weight is distributed
to the tongue, towing will be erratic. Too much tongue weight may overload the towing vehicle’s rear axle or the pintle hitch rat-
ing. Ten to twenty percent weight transfer is considered a normal range. Smaller, single axle trailers can transfer weight on the
high side of this range. Larger, multiple axle trailers are designed to transfer less because of the limited capacity of the towing
vehicle’s rear axle.
When necessary, tongue weight can be controlled by distributing the load or by adjusting the pintle eye. Even loading is
ideal, but when this is not possible, place more weight toward the trailer front to provide a safe tongue weight. Be aware that too
much tongue weight from an uneven load can overload tow vehicle components. It is incumbent upon the operator to provide a
safe, towable tongue weight without excessive hitch weight transfer that could place the tow vehicle in a non-compliant condi-
tion. If your trailer is equipped with an adjustable eye, lowering it will generally increase tongue weight while raising it will de-
crease tongue weight - especially on multi-axle models. Additional loading instructions may be included with your trailer, and
should be followed.
Once the trailer pintle eye is secured in the towing vehicle hitch, cross the safety chains and connect them to the rings
provided at the towing vehicle bumper. Insert the electrical connection cord and check trailer lighting. Connect the air glad
hands if present and check brake operation. Ensure the trailer axle(s) do not exceed their GAWR and the entire trailer and load
does not exceed the GVWR rating.
Operation & Maintenance Manual
Model 1570-B Puller
09/2010
Page 4
