Product Manual

TIE DOWN ENGINEERING • 255 Villanova Drive SW • Atlanta, GA 30336
www.tiedown.com [phone] Fax [phone]
Installation Instructions and Service Manual
Model 66/660*
Actuator for
Trailer Brakes
6,600 lbs Capacity
Drum Brake Ready or
Disc Brake Ready
US Patent No. 6,375,211
MODEL 66 ACTUATOR INSTALLATION INSTRUCTIONS
IMPORTANT: READ AND UNDERSTAND THE ENTIRE INSTRUCTION/ASSEMBLY PROCEDURE BEFORE INSTALLING YOUR
BRAKES AND ACTUATOR.
The Model 66/660 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 dampening shock absorber retards the telescoping shock
against the hitch ball.
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.
Read your tow vehicles owner’s manual on towing capacity and other towing recommendations before installing brakes or this actuator.
The Model 66/660 Actuator is completely assembled and ready to bolt into place (Tongue sizes: 3”x 3”, 3”x 4” & 3”x 5”).
1. Bolt the actuator to the tongue-using grade 5 bolts 1/2 inch in diameter, 4 inches long. Lightweight tongues, less than 11 gauge, require
spacer tubes inside the tongue for reinforcement. Attachment strength should equal or exceed than 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 heavy-duty brake fluid in the Model 66 actuator. Use a pressure type brake bleeder to bleed brakes. (This type of
brake bleeder is available at your local automotive jobber.) Follow manufacturer’s directions. Or, manually bleed the brakes using a
heavy-duty flat blade screwdriver inserted in the hole provided on top 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 7 for more details.
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 glass 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 bleed 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 3/8” below the top of the reservoir and filler cap is securely in place.
061812,C1250
Instruction #08162
*Model 660 - Manufactured
after March 2012