Tie Down LP850 User Manual

Model LP850

Actuator

Owners Manual

Installation Instructions and Service Manual

Model LP850
Actuator* for
Trailer Brakes

8,500 lbs. Capacity
Disc Brake Ready

*US Patent No. 6,375,211

Table of Contents Page

Actuator Installation Instructions 3
Hitching the Trailer 4
Vehicle Wiring - Free Backing Brake Solenoid 5
Actuator Maintance 5
Warnings 6-7
Bleeding Instructions 7-11
Parts Diagram 12-13
Limited Warranty 14-15

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© 2013 TIE DOWN ENGINEERING, ALL RIGHTS RESERVED

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MODEL LP850 ACTUATOR INSTALLATION INSTRUCTIONS
IMPORTANT: READ AND UNDERSTAND THE ENTIRE INSTRUCTION/
ASSEMBLY PROCEDURE BEFORE INSTALLING YOUR BRAKES AND ACTUATOR.

The Model LP850 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. A
knocking noise from the actuator during breaking could indicate low fluid level, check
immediately.

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 LP850 Actuator is completely assembled and ready bolt in place, if needed.

1. 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.

2. Use only DOT-3 heavy-duty hydraulic fluid in the Model LP850 actuator. Use a
pressure type brake bleeder to bleed brakes. (This type of brake bleeder is
available at your local automotive supplier.) 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. 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.

To bleed master cylinder and brakes, the bleeder hose must be attached to the
highest (top) valve on the caliper, 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.

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3. Check with your state motor vehicle department for laws concerning minimum
trailer brake requirements. Some states may require brakes on all axles.

4. Road test trailer a short distance to activate the actuator several times. Check fluid
level again. Remember, low brake fluid levels will result in hitch ball knocking
and loss of breaking power.

5. When 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. Road test again to
make sure brakes work properly.

RATED CAPACITY: Maximum Actuator Capacity: Model LP850 = 8,500 lbs.
Gross Load, 850 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 (Note: G.V.W.R. is the Gross Vehicle Weight Rating which includes the
trailer and the load weight as a Total Gross Weight).

HITCHING TRAILER

1. The vehicle, towing hitch and ball must have a rating equal to or greater
than trailer G.V.W.R.

2. Model LP850 will accept 2” trailer hitch balls rated for 8,500# or more only. Trailer
balls larger than 2.00” or out of round will not fit the coupler or may result in
coupler failure. Balls smaller than 1.970” can cause shock loading and sudden
disconnection. Make certain ball latch is in correct position to retain the hitch ball.
Insert safety pin into forward hole as a safety lock for the hitch ball coupler prior
to towing. Do not tow trailer if coupler is damaged.

3. Connect safety cables or chains using crossed pattern under tongue, or follow
trailer manufacturer’s directions.

4. Connect actuator breakaway cable S-hook to the tow vehicle only. Do not
connect S-hook to the safety cables or chains.

5. The breakaway system is designed to only operate after the trailer detaches from
the tow vehicle and the safety chains have failed. The breakaway is not a parking
brake. Do not use as such.

6. If the breakaway is accidentally applied while un-hitching, too release the
emergency brake, simply press the E-Stop release upward (located on bottom front,
right side of actuator) you should here a “click” noise, this will indicate the bracket
is released.

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7. Any control devices that restrict operation of the actuator cannot be used. This
includes certain sway control devices. The actuator must be free to telescope in
response to braking requirements.

8. Equalizing or weight distributing hitches may be used, allow six to eight inches
free chain length.
DANGER: Tongue weight beyond rating limits will interfere with performance

of actuator, and braking system, and the tow vehicle.

9. The actuator is designed for use with Free-Backing trailer brakes. To block
braking action, (in order to back up) with other types of brakes, use an
electric solenoid. For trailer movement when brakes are not required, place the
safety pin in the upper hole on the side of the actuator to block movement of the
actuator.
DANGER: Failure to remove pin will also prevent forward braking. Pin must

be in the lower, forward hole as a safety lock for the hitch ball coupler latch
when towing at all times.

DIRECTIONS - VEHICLE WIRING - Free Backing Brake Solenoid

1. Disconnect trailer hitch and any wiring connectors from the vehicle.

2. Connect a 14 gauge wire to the backup (reverse) light wire of the vehicle. This
wire should be of sufficient length to attach to the existing vehicle/trailer
wire receptacle. The end of this wire will require a female end that will match the
solenoid male connector wire. Your vehicle may have a 5 wire connection for
this purpose.

3. For ease of use, tape or band the end of the reverse light wire to the vehicle’s
trailer electrical connector.

MAINTENANCE

1. Always check the brake fluid reservoir before using trailer. Make sure it is at
least half full. If not, re-fill to 3/8 inch below the top of the reservoir with DOT 3
brake fluid. Check for leaks and repair as required. Never reuse brake fluid.

2. To extend coupler and ball life, coat both with a thin coating of grease. This will
also eliminate squeaking. Wipe clean and renew coating each time trailer is used.

3. Examine the actuator for bent parts or wear each time the trailer is used.
Replace parts as necessary.

4. There are no user adjustments on the actuator.

5. Actuator travel (shown by coupler roller path) over one inch indicates a need to
adjust the brakes or add fluid to the reservoir or a need to bleed the brakes and
check connections for leaks. Adjust per instructions found in brake
installation manual. In general, back-off adjusters on drum brakes from locked
position, as required. Adjust Free-Backing brakes by rotating in forward direction
only. Failure to adjust may result in loss of braking. Disc brakes do not require
adjustment, check for pad wear.

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