Model 66 Actuator
How to bleed the master cylinder and brakes on a Tie Down Engineering Model 66 Actuator:
- 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.
- Install hydraulic brake lines on the trailer as described in the brake installation manual. Note: Some disc brakes require the use of flexible brake lines at the connection point on the brake caliper..
- Ensure the vehicle, towing hitch, and ball have a rating equal to or greater than the trailer G.V.W.R.
- The 660E will accept 2” or 50mm trailer hitch balls only. Ensure the ball latch is in the correct position to retain the hitch ball and insert the safety pin as a lock.
- Connect safety cables or chains in a crossed pattern under the tongue.
- Connect the actuator breakaway cable S-hook to the tow vehicle only.
- Use an electric solenoid to block braking action when backing up with other types of brakes. Insert the safety pin in the actuator housing to block movement when brakes are not required.
- Equalizing or weight distributing hitches designed for use with surge brake actuators may be used.
* The quick connect “Drop N Go” latch must be in the DOWN position first. Lower the coupler down onto the tow ball using the weight of the trailer. You will visually see the latch snap into place with an audible click. Then insert the safety pin directly through the latch
Additional resources:
- Disconnect the trailer hitch and any wiring connectors from the vehicle.
- Connect a 14 gauge wire to the backup (reverse) light wire of the vehicle. Ensure the wire is of sufficient length to attach to the existing vehicle/trailer wire receptacle.
- For ease of use, tape or band the end of the reverse light wire to the vehicle’s trailer electrical connector
The 660E Actuator has a maximum capacity of 6,600 lbs. Gross Load and 660 lbs. Maximum Tongue Load. The actual in-service rating is limited to that of the ball and hitch being used or the trailer manufacturer’s G.V.W.R. shown on the certification label, whichever is lower.
- Install a bleeder hose on the first wheel cylinder to be bled; if tandem axle trailer, bleed the furthest axle first and the furthest brake on that axle first.
- Use a loose end of the hose from the bleeder valve submerged in a glass container of brake fluid to observe bubbling. Loosen the bleeder screw located in the wheel cylinder one turn.
- Insert a flat tip screwdriver into the bleeding access port on top, near the front of the actuator cover. Use a pumping action to activate the master cylinder.
- Bleed each wheel cylinder until all air is out of the lines, replenishing the brake fluid during the process.
- Ensure the master cylinder is filled to 3/8” below the top of the reservoir and the filler cap is securely in place when bleeding and testing are completed.*
*Use only DOT 3 heavy-duty brake fluid in the 660E actuator.
*Bleed the brakes using a pressure type brake bleeder or manually using a screwdriver in the provided hole on top of the actuator near the front.
*Check state motor vehicle department laws for minimum trailer brake requirements.
*Road test the trailer a short distance to activate the actuator several times and check fluid levels again.