TECH TIP TUESDAY – LINE LOCK NOT OK FOR PARKING BRAKE!

WE HAVE SEEN – WE HIGHLY RECOMMEND AGAINST IT!!!
The use of a “Line Lock” for Parking Brake!

We recently had a rig come in with an issue of its “parking brake” not holding the heavily cladded, overland-equipped 40-Series Toyota Land Cruiser in a “parked position.” Upon inspection, the rig is using a “line lock” for a parking brake. The diagnosis is that after just a few minutes, the solenoid line lock is heating up and can no longer hold the desired pressure required to hold the weight of the vehicle.

TECH TIP TUESDAY - LINE LOCK NOT OK FOR PARKING BRAKE! TECH TIP TUESDAY - LINE LOCK NOT OK FOR PARKING BRAKE!
We tested to see how hot the electrically driven solenoid was heating up to and releasing pressure. It’s all a sliding scale of pressure, heat, and time.
Also, this creates a direct drain on the battery when in use.
Also, this creates a direct drain on the battery when in use.
Also, this creates a direct drain on the battery when in use.

Upon further investigation, the particular line lock in use is for supplemental & temporary brake holding. Even these “heavy duty” industrial line locks are to be used in conjunction with a vehicle’s mechanical parking brake. These line locks perform as operational parking brakes only such as a dump-truck stopped to dump a load. Line Locks are not intended for prolonged “unattended” parking. Thus, this is not the optimal parking brake solution.

The Line lock was initially only used as a temporary device to lock the front wheels for some smokey burnouts! OK, there are industrial applications as well, but again, only for temporary use. Let’s “lock-in” further on this “line lock” apparatus!

First, talk about the fun “line lock” stuff – DRAG RACING!
Line locks are often used for burnouts by fully locking the front wheels, engaging the gas pedal, and disengaging the clutch pedal. This makes the rear tires spin but keeps the car stationary. In drag racing, manual transmissions allow drivers to control the amount of power transferred from the engine to the wheels by manipulating both clutch and throttle inputs, allowing vehicles to accelerate quickly without losing traction. However, launching a vehicle requires simultaneous gas pedal and clutch pedal inputs, preventing drivers from manipulating the brakes with their feet.

Without brake input, drivers staging their vehicle at the starting line would roll if the clutch was slightly engaged. If the driver’s vehicle rolled across the staging line before the start of a drag race, the driver could “red light” and be disqualified from that race, nullifying the results or being declared DNF or a “Did Not Finish,” which is not good!

Let’s talk about the work world or the industrial side of “line lock” stuff! 
Mico is a manufacturer of line locks and other brake products for a wide range of industrial and commercial uses.

The above industries look like fine examples of commercial and industrial use! But too, right there on the Mico’s “Brake Lock” page, they state, “MICO® Brake Locks are for supplemental brake holding and are to be used in conjunction with a vehicle’s mechanical parking brake. They perform as operational parking brakes only and are not intended for prolonged parking. Several brake lock solutions are available for single, dual, split, or anti-lock brake systems. The MICO portfolio includes electrohydraulic, dual lock, lever, twist, cable actuated, and electrically activated. MICO® Brake Locks are ideal for construction, mining, agriculture, material handling, multi-stop delivery, and recreational vehicles. They fit most medium and light duty trucks equipped with a hydraulic braking system.”

In most vehicles with rear drum brakes, two emergency brake/parking brake cables actuate the brake drums mechanically but with much less force than is available through the primary hydraulic brake system. It is common for this type of system to work well when facing downhill but be unable to hold the vehicle stopped without using wheel chocks when facing up a steep hill. An improvement over stock parking brakes is helpful for off-road vehicles such as tractors, tow trucks, 4x4s, construction vehicles, or any drum brake vehicle on ice or steep terrain. Some manufacturers use a transmission brake which locks the entire drivetrain.

In order to park by using the primary hydraulic brakes, a hand-operated valve is added to lock hydraulic pressure in the brake line. Two valves may be necessary for parking using the brakes on all four wheels. Any leakage at the brake cylinders will reduce pressure in the line and release the brakes. For this reason, line locks should only be used temporarily.

This is what is in the customer’s rig:

Now… We get it; we want our rigs to stay put!

We know it’s an “issue” in keeping our 40-Series Land Cruisers parked!
With all this “stay parked mystery” of our FJ40s, maybe this is truly the reason Toyota has a part number: 09184-00010 designed specifically for such tasks along with safely changing tires.

Guess we will need to make a para-cord tether kit to go from chock to door handle and an additional jet-tag keychain “WHEEL STOPPER ENGAGED” reminder so we don’t forget we have our factory folding Toyota Wheel Chocks holding us in the stopped position! We are in no way making fun of the customer, but making light of the situation at hand as we know there is no “ultra-parking-solution” for FJ40’s. Yet…

PS: Don’t keep your rig’s manual transmission in gear while sitting at the stop light. Keeping your gears engaged while at a stop and not moving causes unnecessary wear on your gears and clutch. So the next time you are stopped, slide it into neutral and take your foot off of the clutch pedal.

Call us to discuss real-world solutions for your Toyota Land Cruiser:

RED LINE LAND CRUISERS
719.638.2003
Servicing and preparing Toyota Land Cruisers for epic adventures since 2007 from Colorado Springs, Colorado.

• OE Split T-Case Assembly Fits 8/80 and newer 40 Series / All 60 Series / All 70 Series Toyota Land Cruisers

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