I'm not Leonard, but I did see a Leonard on TV in the late 1960's (Leonard Nimoy... hey, another "N"!) , so...

1) Yes.

However, there are differences in line lock method and actuation, ABS brake system applications, and wheel lock brake line circuit implementation.

I'll discuss six or seven different MICO line lock methods and actuations later on, in answer to Question # 3, further below.

As for the different ABS brake application, there is RABS (Rear Wheel ABS only) and 4WABS (Four Wheel ABS, in either 3 channel, or 4 channel variations). Most of us in this subforum are likely to have 3 Channel 4WABS, but some may have just RABS. (Newer Ford Super Duties have 4 Channel 4WABS) The type of ABS system that a vehicle has can make a difference in selection of MICO line lock.

Wheel lock brake line circuit implementation can vary with purpose. For example, if someone had a drill rig attached to the back of their truck to drill pier holes for residential foundations, and the drill rig had deployable outriggers that raised the rear of the truck off the ground a bit while drilling, then obviously they would want the MICO line lock to apply the front brakes, rather than the rear. On the other hand, an aerial bucket truck would likely want all four wheels locked, as the which tire remains on the ground after leveling the rig for bucket deployment may vary.

2) The more wheels that are line locked, the more clamping force and friction holding contact area is brought to bear to resist the rotation of the vehicles wheels under the weight and influence of gravity wanting to send the truck down a hill.

And on this safety note of a truck hurtling down hill, I'd like to skip Question #3 for a minute and move directly to Question #4

4) There are some risks with using line locks, and these risks exist to a greater or lesser degree depending on what type of line lock is used.

The basic risk is that hydraulic fluid is not considered an "inexhaustible" force. If the brakes and brake fluid are hot when the line lock is applied, the hydraulic force will dissipate as the brake fluid cools. Cooling causes the fluid to contract, and the contraction reduces the force applied to engage the service brakes as a "parking brake". Also, any given lip seal or fitting in a hydraulic system can leak, and the leakage can dissipate the force applied to the brakes.

If we are driving with such leaks, we press the brakes harder, thus increasing the volume of fluid force applied at a rate greater than the dissipation of that force through seepage or leakage. Temperature swings in the hydraulic fluid can also be compensated for by the varying force of our foot. But with many line locks, in particular the less costly and thus more commonly used line locks, there is no mechanism to dynamically adjust force for variation. If the fluid cools, the fluid contracts, reducing the force. If the fluid leaks, the force dissipates, reducing the force. Thus, hydraulic actuation cannot be considered an "inexhaustible" force.

As such, a hydraulically actuated brake does not meet the FMVSS definition or requirements for a "Parking Brake". Here is some of the language of the applicable Federal Standards:

49 CFR § 571.105 - Standard No. 105; S5.2: Parking Brake System.

Each vehicle shall be manufactured with a parking brake system of a friction type with a solely mechanical means to retain engagement...

49 CFR § 393.41 - Parking brake system.

(c) Vehicles not subject to FMVSS Nos. 105 and 121 on the date of manufacture.

(1) Each singly driven motor vehicle not subject to parking brake requirements of FMVSS Nos. 105 or 121 at the time of manufacturer, and every combination of motor vehicles must be equipped with a parking brake system adequate to hold the vehicle or combination on any grade on which it is operated, under any condition of loading in which it is found on a public road (free of ice and snow).

(2) The parking brake system shall, at all times, be capable of being applied by either the driver's muscular effort or by spring action. If other energy is used to apply the parking brake, there must be an accumulation of that energy isolated from any common source and used exclusively for the operation of the parking brake.

Exception: This paragraph shall not be applicable to air-applied, mechanically-held parking brake systems which meet the parking brake requirements of FMVSS No. 121 (S5.6).

(3) The parking brake system shall be held in the applied position by energy other than fluid pressure, air pressure, or electric energy. The parking brake system shall not be capable of being released unless adequate energy is available to immediately reapply the parking brake with the required effectiveness.

In the two Title 49 Code of Federal Regulations quoted above, FMVSS Standard 105 was listed first, as it applies to our class of pickup trucks and chassis cabs with hydraulic service brakes.

The next regulation listed was 49 CFR 393.41 (c), which is conceptually instructive, but applies to vehicles manufactured prior to 1983, which were not subject to Standard 105, nor FMVSS Standard 121, which is also referred to in an exception. FMVSS Standard 121 applies to air brake vehicles, and involves complexities beyond the scope of our application here, and thus is not quoted.


With all of the foregoing understanding of the potential risks and the defined standards for parking brakes under our belt, it becomes easier to compare the distinctions between the 3 different MICO line locks available for our trucks, so we can finally circle back to and address Question # 3

3) The installation will look different, depending on the type of MICO line lock installed. I'll cover six or seven different types of line lock systems from MICO briefly below, from the most effective (and expensive), to the least effective and most potentially problematic (and cheapest).

3A) MICO Part # 02-691-305

This is the MICO line lock system that positively applies pressure from it's own pump while using it's own actuators and fluid resevere. For 3 Channel ABS Super Duty trucks over 10,000 GVWR, and/or where Aerial Lift use is expected.

(For RABS single channel rear wheel ABS applications, and other application deviances, see Roman numerals (i - xi) within this subsection 3A below)

(Approximately $1,700.00 to $2,000.00 in parts, with up to an estimated 14 hours of installation labor time, unless in an efficiently managed mini-manufacturing environment with ready made lines, fittings, brackets, and harnesses for repeated installations, such as what may be arranged at an upfitter plant that routinely installs this system on chassis cabs, such as Altec, as an example.)





If you are serious about the truck not moving when you walk away from it, then this is the MICO line lock system to get. (Or any of the 691 series, as listed in 3A (i) through 3A (ix), at the end of this subsection.

The key: It has it's own Pump / Power Unit.

Conceptually, this means that if you apply the line lock when the brake fluid is hot, and the brake fluid cools and contracts, this system will sense a loss of pressure and apply power to it's own pump to keep the pressure up in your absence.

I say conceptually, because this system actually uses it's own supply of brake fluid separate from the service brake fluid, so heat from the service brake fluid will not directly effect the reserve supply of fluid dedicated to actuating the service brakes when parked.

This system also employs huge powerful actuators, capable of 800 psi of applied pressure, and able to displace nearly 3 cubic inches of brake fluid per cylinder.

The controls for actuating the system can be linked to other actions.... such as applying the OEM parking brake, or opening the fill hatch for on board propane cylinders, or deploying the outriggers for a bucket truck, or whatever other parameter you might like to automatically engage this line lock system.

This is the real deal. The abiltiy of the pump to compensate for any pressure loss from leaks in the system reduces the risk of the brakes letting go over time, temperature changes, and/or other factors that might cause gradual pressure dissipation.

Everything else from MICO or copy cat AFCO is several rungs down the ladder in performance, risk of failure to apply or release, and price.



3A (i) IF Single Channel RABS, and NOT DRW, and Under 10K GVWR, and want ALL 4 wheels locked, then order 02-691-209.

3A (ii) IF RABS, and want only 2 REAR Wheels locked, regardless of DRW or over/under 10K GVWR, then order 02-691-109.

3A (iii) IF RABS, and want only 2 FRONT Wheels locked, regardless of DRW or over/under 10K GVWR, then order 02-691-223.

3A (iv) IF 3 Channel 4WABS, and want only 2 REAR wheels locked, regardless of DRW or GVWR, then order 02-691-109

3A (v) IF 3 Channel 4WABS, and want only 2 FRONT wheels locked, regardless of DRW or GVWR, then order 02-691-223

3A (vi) IF 3 Channel 4WABS, and want ALL 4 wheels locked, regardless of DRW or GVWR, then order 02-691-305

3A (vii) IF 2011+ 4 Channel 4WABS, and want ALL 4 wheels locked, regardless of DRW or GVWR, then order 02-691-403

3A (viii) IF 2011+ 4 Channel 4WABS, and want only 2 wheels locked, whether front only or rear only, regardless of DRW or GVWR, then order 02-691-209

3A (ix) If wanting to upsize from 1-1/4" bore diameter actuator cylinders to 1-3/4" bore diameter actuator cylinders for double dual cylinder kit such as the 02-691-223, then substitute with 02-691-201

3A (x) If wanting to upsize from 1-1/4" bore diameter actuator cylinders to 1-3/4" bore diameter actuator cylinders for single acting cylinder kits such as the 02-691-109, then substitute with 02-691-101.

3A (xi) An 02-691-305 with 1 dual cylinder (for the front 2 ABS channels) and 1 single cylinder (for the rear shared ABS channel) comes with 1-1/4" bore diameter actuator cylinders, and thus might have to be custom ordered a la carte to substitute the larger 1-3/4" bore diameter cylinders, as no kit is listed in that configuration. All other parts in all 691 kits are the same.



3B) MICO Part # 02-640-169

This is the MICO Dual Cable Lock system that works with both 3 Channel 4WABS, locking both front wheels only, or Single Channel RABS, locking front and rear wheels.

(Approximately $750.00, with unknown estimate of labor installation time)

Actuation method is Pull Out, Push In handle, typically dash mounted. An advantage to the Cable Lock is that the lock actuation hardware can be remotely mounted under truck, while the cable is routed to the operator's preferred position.



Above... configured for 3 Channel 4WABS, activating the two front brake circuits. Notice the stringy aircraft cable drawn upward from the remote mounted actuation and check valve up to the dash board. Care must be taken to route this cable to avoid kinking or binding.



Here is the **** that the end of the cable attaches to:




Below... configured for Single Channel RABS, activating the rear brakes (after the Rear ABS module) and the non ABS front brakes before the left right split.




The dual cable provides a lower cost alternative for single channel RABS owners to have all four wheels lock, or for 3 Channel 4WABS owners to have their dual circuit front wheels lock.


3C) MICO Part # 02-640-023

This is a MICO Single Cable lock that actuates 1 brake circuit, which generally would be the rear circuit on 3 Channel 4WABS trucks. It could also be the front or the rear (but not both, unlike the Dual Cable Lock) in RABS trucks.



The method of actuation is a Pull On, Push Off **** just like the Dual Cable Lock described above, where the valve is remotely mounted with a cable leading up to the operator's prefered location to mount the ****.


3D) MICO Part # 02-640-125

This is the MICO Lever Lock. Limited to the same single brake line circuit applications as the Single Cable Lock, the Lever Lock adds a more reliable engagement/disengagment actuation "leverage", literally.

The only caveat is that one must have significant clearance room both in front of (for the up and down swing arc of the lever), and behind (for the one way check valve) the dash panel or control board where it is positioned.

If the higher GVWR rated MICO 691 series is out of the running due to cost, and only a single simple line lock is desired for an under 10,000 GVWR pickup, actuating only a single axle (two wheels) then this Lever Lock is the product that MICO recommends over any other single brake circuit actuator in the 640 series. MICO also recommends the Lever Lock over the now discontinued 620 series electric switch actuator, for reasons discussed further below, under the 620 series replacement part number.

If all four wheels are desired to be locked, then either a 691 series (if 3 Channel 4WABS) or the Dual Cable Lock in the 640 series (if and only if RABS) is recommended, as discussed earlier above. The 691 series is superior, but the Lever Lock 640 series is more reliable than the electrical switch 620 series.





3E) MICO Part # 03-640-075

A variation of a theme, this is the MICO Twist Lock version of the Lever Lock, changing only the method of manual manipulation of the valve actuator from and up and down lever to a rotational twist.




Before we go any further in discussing the remaining two versions of MICO line locks, somthing to keep in mind is that in all of the 640 series listed above, the mechanical energy to apply the MICO line lock comes from the operator's hand, via either a dial that is twisted, a lever that is thrown, or a **** that is pushed and pulled.

In the previously discussed 691 series, there is an entirely separate electric motor and pump that supplies the energy and pressure to line lock the brakes.

However, in the two remaining MICO line lock systems discussed below (which are both the same really, as the latter supersedes the former) there is only a low power electric switch, so the energy to apply the pressure to lock the brakes must come from the foot applied to the service brake itself, to not only apply, but to also RELEASE the brake hold when it is time for the truck to move again. This is a critical distinction between the line locks already listed above, and the ones about to be discussed below.


3F) MICO Part # 02-620-009

This is the MICO part number that @ESwift linked to in this post in a concurrent thread discussing OEM parking brake failure begun by @materthegreater .

These FTE referrals are one of several reasons why I mention this part number, which has been discontinued by MICO.

However, various retailers may still have new old stock still available for purchase, internet searches will still bring this part number up.

MICO states that this Electric Activated Brake Lock IS NOT TO BE INSTALLED IF YOU HAVE 3 or 4 CHANNEL ABS (4WABS Anti Lock Brakes).

This system should only be installed on trucks without ABS, or with only RABS (Rear Wheel ABS).

This MICO line lock, if properly installed, will lock the FRONT wheel calipers. See 3G below for a diagram.

This electrical switch activated line lock has all the problems explained further below, under it's replacement part number described in 3G, which follows.

ZF (of Germany), the same ZF that made the 6 speed in our trucks, acquired WABCO in 2020, and WABCO (of Belgium) had acquired MICO, Inc (of North Mankato, Minnisota... ahem anywhere near your neighborhood @FordTruckNoob ?) in 2016.

MICO revised and replaced 02 620 009 with a new part number, likely using a European part number numerology scheme, considering the headquarters location of MICO's two recent ownership changes.


3G) MICO Part # 408 128 000 0

This is an electrical switch activated line lock. It replaces the now discontinued MICO 02-620-009, referenced in 3F, immediately above.

MICO states that this Electric Activated Brake Lock IS NOT TO BE INSTALLED IF YOU HAVE 3 or 4 CHANNEL ABS (3 Channel 4WABS Anti Lock Brakes).

This system should only be installed on trucks without ABS (of which there are none in the 1999-2003 Super Duty line), or with only RABS (Single Channel Rear Wheel ABS).

This MICO line lock, if properly installed, will lock the FRONT wheel calipers.







Problems and issues with this electric switch lock:

- To release the line lock, after flipping the switch, one must press on the service brake HARDER than what one pressed when the line lock was initially applied. If different operators use the truck, the amount of foot pressing power can change from person to person, so the second person may not be able to press hard enough to release what the previous person applied.

- The following cautionary "NOTE" only applies to this particular style of electric switch line lock, including the discontinued 02-620-009 (and other part numbers in the 620 series) and the replacement 408-128-000-0. The NOTE speaks for itself as to the inherent problem with this type of line lock system, so be sure and read it all the way until the end of the final sentence within it. What a pain.


- If the truck ends up stuck with the line lock applied, it may be necessary to bleed the brakes to release the pressure, either at the wheel, or at the inlet, or the entire system.

- The Electic Activated line lock has to be installed on the primary circuit (nearest to the firewall) which ends up being the front brakes. But if the vehicle has 3 channel ABS, then this Electric Switch line lock cannot be used at all.



- Compared to the line lock models identified in 3A-3E that MICO recommends for the Super Duty, it should be understood that MICO does NOT recommend the line locks listed in 3F-3G for the Super Duty, or any other vehicle application listed in the MICO Application Guide. MICO tech support advises to consider either the Lever Lock... or the 691 series... instead of this Electric switch activated model,

So, between the conspicuous absence of this particular model of line lock in MICO's vehicle application guide, combined with the warnings in the brochure/sales literature made in advance of potential purchase, combined with reading the things gone wrong in the Troubleshooting Guide on the installation instructions, and being told in person by MICO's tech support... MICO has established that this particlular model of line lock is not MICO's best offering, and that MICO offers better options to choose from, as illustrated in 3A-3E above.

Given the recent interest on the forum in MICO line locks, it seemed timely to clarify the distinctions between the models, and @F250_ 's series of questions provided a springboard to explore these differences, and by so doing, discover some of the risks.. which are not insurmountable, but are intrinsicly linked to an appropriate match of MICO line lock product to vehicle application, ABS brake type, number of wheels desired to be locked, and if less than all four, on which axle are the locked wheels desired, how much weight the vehicle carries or is rated to carry, how many different operators utilize the vehicle, how steep of grade will the brakes be necessary to overcome, how expansive are the thermal swings in temperature in the operating locale, etc...

No matter which MICO line lock is selected, none meet the statutory definition of parking brake, while some work more effectively and consistently than others.

 

Wow, that is a ton of good info!

With my electric unit. My trucks have rear abs, the truck with the mico unit has it installed to hold the rear axle brakes. It is installed on the inside of the frame rail in front of the fuel tank. Even though it is stated not to use with the abs, it does not affect it in any way because the mico unit is after the abs controller, and only pressurizes back to the rear brakes.
Things to note: the clamping force will dimminish as hot brakes cool, generally speaking if I park my zf6 truck on a hill with the mico locked, it will in about an hour set off its low pressure alarm switch which I have wired to a 12v reverse beeper(obnoxiously noticable). If I then restart truck and reset the mico it will hold all day with cool brakes. The loss of clamping force is not an issue or safety concern for me because I chock my wheels. When loading heavy equipment on a trailer I chock front wheels so it doesnt roll away if it lifts rear axle.
I have been using this mico for several years. It gets used a lot. In the winter when plowing it gets used in excess of 100 times a day 7 days a week. Every time I step out to bust frozen cinder, load more cinders, unlock a gate, etc. It will hold my truck at 18,000 pounds loaded on a %14 grade, I have come to trust it so much I will lock it, let truck in N idling (zf6) drop my plow down and then get out and climb on top of the bed to push frozen cinder down, all while on a steep hill. I have since added 3-200lb vibrators to my spreader, so much less need to deal with stuck cinders by hand(we use 1b washed stone for cinder)
I quickly lock mico, hop out and grab something, many times I have gotten to where I just push in pedal, flip switch, release pedal, then flip switch off. This will lock it and it will remain locked until brake pedal is pushed again. This way when I get into the truck my natural process of pushing in pedal, then clutch will unlock it as I use my plow control, spreader control, shift, talk on cb radio, and chug coffee, and take off! No need to flip switch off :-)
The truck will not move at all if I try and drive away with it locked, but bad things can happen to driveline if one would try hard enough, it REALLY holds.
Back when I got it, it was about $300 and took me about 2hr to wire up, cut and flare brake line where it installs etc. I also ran new ss braided hoses in place of all 5 oem rubber ones, and new ni-cop lines from the mico unit back. Which added a little time to that 2hrs.
If I ever built another old rig from a 450-550 chassis, I would most likely spend the coin on y2k's first posted option, but not on a 300,000 mile rusty dented work truck that gets the snot run out of it.

 

That is quite the dissertation. I think it deserves to be added to the Tech Folder to preserve it for posterity. Thank you for covering where I fell short.

 

One thing I will add to all of this, is I would never depend on a line lock system for long periods, my initial intention was only for short periods while the engine is running. I have used Mico hub locks on equipment I used to design, and Mico made sure to say to not rely on the system solely. They were hydraulically controlled, and required fluid to unlock the system, which is different than a line lock.

 

Simple solution: Convert to air brakes!! Make sure you have a leak in your compressed air system so the brakes default to engaged.

@Y2KW57 , you shush about this.

 

Hard pass, pneumatics are my absolute least favorite method of controlling anything.

 

I’ll let the others tell you how serious I am about my previous statement.

 

Wow. Just WOW!

I concur that the Y2K's compiled list of options and Pros/Cons are worthy of being cemented into our Tech Folder as a very valuable reference.

As for me... I think I'll end up relying strictly on a mechanical rebuild with stock parts and try to stay on level ground when possible.

 

Has anyone ever looked into something similar to this?
Wilwood Disc Brakes 140-15979-BK Wilwood Electronic Parking Brake Rear Retrofit Brake Kits | Summit Racing

I would rather do something like this than a line lock system.

 

On all stripped and cutaway and rv chassis.
I have it in my e450 30’ 2002 advwnturer anniversary edition. I’ve just checked google and as cheap as 350-450usd or 480cad. It’s strong enough to keep my 17.8k lbs rv on the steepest hills imaginable and by far the strongest I’ve seen. Highly adjustable too. Be careful not to forget it on as driveshaft spins faster than wheels and damaging it is quicker as a result. If u can get ur truck to move in D. I did it in 1 on the shifter. Lucky u smell it quicker as it is directly under cab.

 

Too simple, people like complicated technology.
Air brakes use the absence of air pressure for parking which is why they are actually spring brakes. Lose air pressure and the wheels lock.

 

U worried about bots?

 

True, but you then have to add a compressed air system to our trucks.

 

By simple I was talking about a driveshaft brake, cable operated by a pedal or lever.
Air brakes would be completely off of the table, totally absurd to want air brakes on a light duty truck.

 

It's just one of those things you have to be aware of on these older trucks especially with an electric brake trailer since none of those have any parking braking ability that I know of. I carry a couple of small rubber tire chocks but try to park on level ground where it'll sit still while loose when possible. Working under or around the truck leaving it in neutral and chocking is probably safer idea if the batteries are connected.