TOWING YOUR APPARATUS
BY TERRY ECKERT
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Towing is a scary subject. No one wants to even remotely consider the possibility of having to tow a piece of apparatus. However, any fire apparatus technician will tell you that towing apparatus is a reality, and the horror stories will usually follow.
MYTH OR TRUTH?
There are many towing myths, and my job is to unravel the myths and get to the truth.
Myth: Electrical components, engines, and transmissions will never fail on any of our apparatus.
The truth is that electrical components, engines, and transmissions do fail. The truth is also that accidents do happen and apparatus does break down.
All tow companies train their operators to tow vehicles with the drive wheels in the air. Heavy fire apparatus is the exception to this rule. Because of the heavy rear-end weight and the extended tailboards, it would be next to impossible to tow them backward. So, to the front we go: hook up, lift, and off we go. Unfortunately, it is not quite that simple. Lifting fire apparatus without damaging the body and frame necessitates having the proper equipment and special skills. And even with proper equipment and special skills, the possibility of transmission damage always exists. If your department is gifted with a standard transmission, put it in neutral and go. If your department has an automatic transmission, you must make some difficult decisions.
Myth: If you tow a vehicle a few feet with a chain, the transmission will always fail.
The reason this myth persists is that no one wants to take the responsibility for buying that transmission if the little gremlins decide that transmission failure will occur at the same time the apparatus is repaired.
Most fire apparatus built today use an Allison automatic transmission. The reason transmission manufacturers limit towing a vehicle with the drive wheels on the ground is that the driveshaft is directly connected to the rear part of the transmission. The rear planetary gear assemblies in the transmission might be moving while the apparatus is being towed. Each of these assemblies is made up of a sun gear, pinion gears, and a ring gear. The planetary gear assemblies make possible the gear reduction that takes place for the different speeds and reverse. When these planetary gears are driven from the driveshaft end, because of the gear reduction, the rear gears may spin much faster than they normally would. Combine the gears` spinning much faster than normally with the fact that no lubrication is getting to these gears (since the engine is shut off), and let your imagination go wild and picture all these gears flying in every direction. This has been known to happen, but usually only under abusive towing conditions.
To avoid any transmission failures or liability problems, most towing companies observe the transmission manufacturer`s rules about towing. The tow companies are going to insist on removing driveshafts, no matter what the circumstances. This is the way they were trained. It can be very challenging and expensive (in some instances, it can cost hundreds of dollars) to remove drive-shafts, and the possibility exists that the U-joints and driveshaft can be damaged or destroyed. Some designs actually prohibit field removal of the driveshaft.
A word to the wise: Review the section on towing in your transmission manufacturer`s manual. For certain Allison transmissions (you will be able to find this information in your transmission manual for the specific apparatus), for example, as long as the problem is not the transmission, you are allowed to push, pull, or tow the vehicle up to one-half mile at a speed of no more than 10 miles an hour. This is good to know if the breakdown occurs just down the street from the fire station. If your apparatus was delivered without the official manufacturer`s manual, make sure you get one as soon as possible. Find out the specific towing guidelines before a breakdown occurs.
Myth: If a pumper is going to be towed a long distance, the driveshafts must always be removed.
The truth of the matter is that on engines with midship pumps that use a split driveshaft, the problem can be solved by shifting the pump into gear. Placing the pump in gear will satisfy Allison`s requirement that the drive wheels be disconnected with the output of the transmission.
The pump manufacturers were quick to point out that a check of the “pump engage” light would be a good idea. If engine or transmission failure occurs, manual rotation of the front driveshaft may be necessary to help the pump click into gear. The pump manufacturers all agree that no damage would occur to the pump case if towed this way. This also aids in the argument for installing manual pump shifts on new pumpers.
If you are not dealing with a split driveshaft, another way to disconnect the rear drive line is to remove the axles. In some circumstances this may prove to be a lot simpler. The best recommendation I can give is to make a list of your apparatus and decide beforehand the easiest way to deal with your drivetrain.
Sometimes to save time, the tow operator will tell you that if the drive lines have not been disconnected and the vehicle is towed at a reasonable speed and distance (which the tow operator assures you he will do), no damage will occur. I cannot and do not recommend that the apparatus be towed in this manner. To allow towing in this manner would make your department–not the towing company–responsible.
PROPER LIFTING OF THE APPARATUS
Axle Lift
Because of the heavy weight of most apparatus, proper lifting is a significant part of the towing operation. The sling-equipped wrecker cannot be used on present-day apparatus. The sling equipment uses the bumper to support most of the weight, and bumpers are not designed to do this. Since the axle is designed to carry the load of the vehicle, it makes perfect sense to lift and pull by the axle. It is a real challenge to accomplish this with extended bumpers and the low angle of approach and departure on most apparatus. To lift by the axle, the tow truck must have a longer than normal extension on the hoist to enable it to reach the axle. And chances are that more extension is required to have the clearance needed for cornering and for uneven and bumpy roads.
Another problem is the teeter-totter effect that results when the vehicle is raised so far behind the tow truck`s rear axles. A long-wheelbase wrecker with two or three rear axles is needed to properly tow the average pumper. If you have to have apparatus towed, make sure the right equipment is dispatched the first time so money and time are not wasted when the wrong tow equipment shows up.
Frame Lift
In some instances, lifting by the axles is not going to be possible because of equipment limitations and because the tow operator will want to lift the apparatus by the frame. Chances are that the tow operator is not going to be familiar with the design of the apparatus. In theory, the frame ahead of the front spring shackles no longer needs to support the entire weight of the vehicle. However, apparatus is usually specified and built with pull tow hooks that can “pull the gross weight of the apparatus.” So if tow hooks (pull-out hooks) are attached to the frame, this is an indication that the frame is probably substantial enough to support the weight of the vehicle.
Warning: Be very careful of towing in this manner. Never lift the apparatus beyond the frame tow hooks. The apparatus frame beyond this point may not have been designed to take the full load of the apparatus. Never, ever lift the apparatus by using the frame extensions that hold the compartments, bumpers, or tailboards.
Parking Brake
The rear parking brake will have to be released before the vehicle is towed. There are two ways to accomplish this. To release and hold the parking brake off, a constant air supply is needed. The first and simplest way to accomplish this is to supply the air pressure from the tow truck through the air lines and fittings. To do this, the apparatus needs to have an air inlet fitting to the air system. Most apparatus already have this feature, which is used to keep the air system charged at the fire station for those quick getaways. If you do not have this outside fill feature, consider installing one.
If a tow operator does not have the equipment to remotely charge the air brakes, the second option is to pull the parking brakes off with a release stud tool. Review using this tool with a brake mechanic or your tow operator. The tools are different for each brake system, so the tow operator may not have the proper tools. These tools should always be available and stored with the apparatus in case of that unexpected breakdown.
Other Points to Consider
When lifting the front of the apparatus by the frame, the front will have to be lifted so high for front-wheel-to-road clearance that the rear tailboard may not have enough clearance. Proper clearance from the tailboard to the road is mandatory for the crowns at intersections, bumps, or heaves that will be encountered on the way to the shop to avoid damage to the tailboard.
A frame lift will most likely need blocking and special securing because the apparatus will more easily shift and move around while being towed.
Consider locating a flatbed carrier if lift towing is not an option.
A tow truck operator may insist on pulling a driveshaft no matter what the circumstances, because this is what he was taught. If you decide to tow the apparatus with the pump in neutral, consider having ready for signature preprinted release forms that will relieve the towing company from the liability of transmission damage. This is the only time–when specifying this method of towing–that the towing company should be relieved of responsibility for damage.
Meet with the owners of the tow company you prefer to engage to review all your concerns. Review pricing before the emergency; it is sometimes cheaper that way.
A towing contract is a good idea, to record the agreement.
Make sure that fire apparatus is a priority. For example, stress the importance of being able to move a pumper in the winter before the water freezes in it.
Always drain the water from the tank. Reducing the weight of the apparatus by thousands of pounds relieves the stress on the apparatus and the tow truck. Water can always be drained by gravity if the pump cannot be operated.
Always use safety chains, should a hookup or equipment fail.
Use temporary stop and taillights.
Liability
Make sure that the tow company you engage has proper liability coverage. Depending on the state in which you are located, accomplishing this may be as simple as making sure that the towing company is properly licensed by the state. Most states require that the carrier maintain ample insurance and be bonded. The towing company must also follow fair business practices to remain licensed by the state. Some states require posting rates (by the hour or by the tow). Check into your state`s laws governing towing companies. Most of the time the Secretary of State`s office will have the answers. If not, you will be referred to the proper office. Be very careful if you have to use an out-of-state towing company or if you cross state lines while towing your apparatus. In some instances, the towing company may have to be licensed in both states.
I have only briefly touched on towing fire apparatus, but many of the same rules apply to smaller vehicles. Different towing equipment will be needed, and the preferred way of towing would be to lift the drive wheels with a wheel lift or car carrier. Since different equipment will be needed for your support vehicles, prearrange for their towing in an emergency also. You may find that you will need a different towing company for different vehicles. n
I would like to thank the following for information for this article: Allison Transmissions, W. S. Darley & Company, Waterous Company, Hale Fire Pump Company, and AAAA Towing in Darien, Illinois.
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The tow truck may need a long undercarriage to clear the extended bumpers on apparatus.
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The tow truck operator is connecting to his auxiliary air supply so that the apparatus parking brake can be released.
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The frame is being used to lift the apparatus. Note the use of the safety chains.
TERRY ECKERT, a 15-year veteran of the fire service, is a firefighter and head of apparatus maintenance in the Darien-Woodridge (IL) Fire District and the chief engineer of the Westmont (IL) Fire Department. He has 25 years of experience as a vehicle technician. He is an ASE-certified master automobile technician and master heavy truck technician and an EVT Level 3 master technician. He also has ASE certification in advanced level engine performance. Eckert is a member of numerous professional associations, including the National Association of Emergency Vehicle Technicians (NAEVT) and the Illinois Fire Apparatus Mechanics Association. He is a member of the EVT Certification Commission, where he serves on the Validation Committee and had chaired the E-3 section, and the NFPA Technical Committee on Emergency Vehicle Technician Professional Qualifications. He was the 1997 recipient of the NAEVT Certificate of Achievement Award.
