TrailMax 8012DT, Manual

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page 27
8012DT
Maintenance
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2.7 Hydraulic Brake System
Operation
The hydraulic brakes on your trailer are much like those on your car. The hydraulic
brake fluid from a master cylinder is used to actuate the wheel cylinder which, in turn,
applies force against the brake shoes and drum. The main difference between automo-
tive hydraulic brakes and hydraulic trailer brakes is the actuation system which transfer
the braking signal from the tow vehicle to the brakes.
The surge braking system uses a specially designed trailer hitch coupler which has
a hydraulic cylinder built in. When the tow vehicle applies its brakes, the tow vehicle
decelerates causing the trailer to apply a pushing force against the hitch. This force
actuates the surge hitch hydraulic cylinder, forcing brake fluid under pressure into the
wheel cylinders, which then causes the trailer brakes to be applied.
Surge Actuator Maintenance
Before towing check that the brake fluid reservoir is full. If not, refill to 3 /
8
inch below
the top of the reservoir with DOT 3 brake fluid. Check for leaks and repair as required.
A film of grease on the coupler will extend coupler life while eliminating squeaking.
Wipe clean and renew film each time trailer is used.
Before towing, examine the actuator for bent parts or excessive wear. Replace parts
as necessary. Check to determine that mounting bolts are tight and welds not cracked.
Some earlier models used the Dico actuator that had grease fittings for the internal
rollers. If your trailer is equipped with this actuator, grease the rollers every 90 days or
5000 miles.
Excessive actuator travel (over one inch) when brakes are applied indicates a need
to adjust the brakes. Adjust per instructions found in the brake section of this manual. In
general, back-off adjusters 10 clicks from locked rotation. Adjust Free-Backing brakes
by rotating in forward direction only.