Tie Down 125 Actuator - Manual

TIE DOWN ENGINEERING • 255 Villanova Drive SW • Atlanta, GA 30336
www.tiedown.com (404) 344-0000 Fax (404) 349-0401
Installation Instructions and Service Manual
Model 125
Actuator for
Trailer Brakes
12,500 lbs Capacity
Part #48780D - Drum Brake Ready
Part #48780B - Disc Brake Ready
Part #48780C - Disc Brake Ready
W/Solenoid Installed
MODEL 125 ACTUATOR INSTALLATION INSTRUCTIONS
IMPORTANT: READ AND UNDERSTAND THE ENTIRE INSTRUCTION/ASSEMBLY PROCEDURE BEFORE INSTALLING YOUR BRAKES AND
ACTUATOR.
The Model 125 works by the “surge” or “push” of the trailer toward the tow vehicle. This automatically synchronizes the trailer brakes with
the tow vehicle axle brakes. When the trailer pushes against the tow vehicle, the actuator telescopes together and applies the force to the
master cylinder, supplying hydraulic pressure to the brakes. The built in sealed and independent dampening shock absorber controls the
telescoping shock against the hitch.
Be sure to comply with regulations for brakes in your state. Brake laws sometimes are minimum standards and you may wish to add
additional brakes to your trailer to meet minimum Gross Vehicle Weight Ratings (GVWR).
Read your tow vehicle owner’s manual on towing capacity and other towing recommendations before installing brakes or this actuator.
The Model 125 Actuator is completely assembled and ready to bolt into place (Tongue sizes: 3”x4” & 3”x5”, 9 ga min.).
1. Bolt the actuator to the tongue-using grade 5 bolts 5/8 inch in diameter, 4 inches long. Attachment strength should equal or exceed
1-1/2 times trailer G.V.W.R.
2. Hydraulic brake lines should be installed on the trailer as described in the installation manual supplied with the brakes. Note: Some disc
brakes require the use of flexible brake lines at the connection POINT on the brake caliper. Follow brake manufacturer instructions.
3. Use only DOT-3 brake fluid in the Model 125 actuator. Use a pressure type brake bleeder to bleed brakes. (This type of brake bleeder is
available at your local automotive parts supply store.) Follow manufacturer’s directions. Or, manually bleed the brakes using a
heavy-duty flat blade screwdriver inserted in the hole provided on the side of the actuator near the front. Insert the screwdriver and use
a pumping action to activate the master cylinder in order to bleed the brakes. See page 8 for more details.
4. To bleed master cylinder and brakes, install bleeder hose on first wheel cylinder to be bled; if tandem axle trailer, bleed closest axle
first, and the closest brake on that axle first. Use a loose end of hose from the bleeder valve submerged in a clear container of
brake fluid to observe bubbling (hose must be submerged into clean brake fluid to keep air from traveling back into the brake cylinder).
Loosen the bleeder screw located in the wheel cylinder one turn; the system is now open to the atmosphere. The bleeding operation
for that brake is complete when bubbling stops. Be sure to tighten bleeder screw securely. Each wheel cylinder must be bled until
all air is out of the lines. Replenish the brake fluid during the bleeding process so the level does not fall below half full level in the
master cylinder reservoir. When bleeding and testing is completed, make sure master cylinder is filled to approximately 3/8” below the
top of the reservoir and filler cap is securely in place.
5. Check with your state motor vehicle department for laws concerning minimum trailer brake requirements. Some states may require
brakes on all axles.
050609
,b771
Instruction #08072