Deep Trouble: Repairing trucks and trailers after a flood

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A major Calgary flood in 2013 caused considerable damage.

TORONTO, Ont. —  Water isn’t kind to electronics or brakes or air systems or engines. The last thing short of a fire you could want to happen to your truck is to have it submerged in flood. Actually, a fire might be preferable — the damage is obvious, and you’ll get less argument from the insurance company about replacing it.

We have seen a rash of severe flooding in Canada in recent years, from this year’s catastrophic floods in New Brunswick and British Colombia to the Calgary flood of 2013. And, of course, there are the perennial storm-related floods along the U.S. Gulf Coast and up the eastern seaboard. Even if your business isn’t located in a flood-prone area, your travels could easily put you into harm’s way.

“Luckily when we had the floods in 2013 we heard of only a handful of heavy trucks being submerged,” says Mike Allen, service director at Great West Kenworth in Calgary. “In each of those instances the water was above the bottom of the door and the insurance companies deemed them to be a total loss. The newest of those units was only a year old.”

The bottom of the door seems to be a cut-off point for flood damage. Several of the people we spoke with suggested that’s where the insurance companies draw the line on writing off the truck, but it depends on the circumstances and the insurance company. Still, a lot of damage can be incurred below the bottom of the door in a contemporary Class 8 truck. The electrical system is perhaps the most vulnerable.


Water and wires don’t play well together. Any time copper wire is exposed to moisture, corrosion is imminent. If the sealed connectors do their job, water should not penetrate the connection, but you’ll need to open each connector exposed to water so it can be inspected, cleaned and dried.

“You have to systematically inspect everything that has been exposed to water,” says John Crichton, director of field service at Navistar. “Starting with the connectors and wiring harnesses, batteries, relays, fuses, terminals, etc. right up to the starter and alternator.”

These parts can be restored, Crichton says, but it would be a mistake to expect normal service from them after a flood.

“The wiring harness may look okay but it’s hard to tell if water has leaked at some point with a nick or a cut in the wire insulation,” he says. “Starters and alternators will probably be OK once they are cleaned out, but again, you can’t see internal damage.”

You would have to weigh the cost of a part-by-part inspection and cleaning versus a wholesale replacement of everything electrical in the exposed areas. The deeper you go the more it’s going to cost, and you’re still left with the uncertainty of future performance. You could see a litany faults from compromised electrical parts for the life of the truck, and with all the electronics on today’s trucks, that’s a lot of uncertainty.

Replacing the exposed electronic control modules could also be an expensive proposition. They are everywhere now, from the ABS system to the HVAC system and everything in between: aftertreatment system, transmissions, engine and more. Generally, these units are considered weatherproof, which is to say normal exposure to rain, snow, road spray and such; immersion in water is another thing altogether.

“Depending on the extent of the immersion, water and debris may get between wires and insulation and initiate corrosion,” cautions Mike McHorse, manager, on-highway product marketing, Freightliner Trucks. “Electrical components should not be washed, and vehicle batteries should be disconnected prior to any service. Electrical items and control modules may need to be replaced.”

Bendix recommends replacing any cab-mounted ECUs while running a thorough diagnostic check on the frame-mounted ECU. “All cab-mounted ECUs that have been submerged must be replaced,” Bendix notes in a pair of technical service bulletins regarding vehicle immersion (Bulletin TCH-003-049 and TCH-003-048 on flooded vehicles). “Unless damaged, frame-mounted ECUs are normally “weatherproof” and are not affected by water or most types of contamination.”

“With advanced safety systems like Wingman, you’ll need to not only download the ACS ECU and run a diagnostic check, but also the radar system’s ECU and the ABS controller,” warns Jim Szudy, engineering manager, vehicle systems at Bendix Commercial Vehicle Systems. “There are pressure sensors, load sensors and a host of electrical components that will need to be checked.”

These are just single-point-in-time inspections, Bendix cautions. The company recommends that vehicles that do not show any internal evidence of water or contamination be retested 30 days after the vehicle has been returned to service. “We also recommend that the vehicle be re‑tested for operation, leakage, and contamination, and that a diagnostic check of the ABS system be carried out,” notes the bulletin.

Axles and driveshafts

The greatest threats to your drivetrain components are rust and bearing damage.

“Water contamination due to flooding or high-water situations needs to be taken seriously with drive axles, steer axles, wheel-ends and driveshafts,” says Steve Slesinski, director global product planning for Dana’s commercial vehicle business. “Contamination to an axle’s grease and oil can cause premature wear to bearings, gearing and sealing systems. That’s why we strongly recommend that thorough inspections and corrective measures always be made to reduce the potential for failures and unwanted downtime.”

Dana says the lube should be drained from axles and checked for water contamination, which can make the lube oil appear milky. If that’s not definitive, try a “crackle” test. Place a bit of the suspect lubricant in a metal pan and heat in on a hot plate to about 400 degrees. Any water present will boil off with a crackling sound. If it just smokes, no water is present.

“Driveshafts and universal joints that have been submerged in water require the same amount of attention as an axle and should not be ignored,” says adds Tom Bosler, senior manager – driveshaft product planning for Dana. “We also recommend that damaged components never be repaired and always be replaced with new OEM-quality parts. Proper disassembly and reassembly procedures are available in all of our Dana service manuals.”

A similar threat exists with transmissions. Water could enter through the vents and so the lube should be drained and inspected. Obviously, any lubricant containing sediment should be changed and the component flushed to disperse abrasive grit.

Steer axle components submerged in floodwaters need to be checked, too. Kingpin joints must be disassembled and inspected for contamination damage including rust and/or pitting of component surfaces. Damaged components should be replaced, never repaired, Dana warns. Tie-rod ends and kingpin seals should be replaced.

Same with wheel-ends. They should be disassembled and inspected for contamination damage including rust and/or pitting of component surfaces. Damaged components should be replaced, never repaired, and new wheel seals installed.

Braking system

This section is not for the faint of heart. Depending on how long the vehicle was underwater, Bendix suggests a range of options from thorough testing of all brake system components for mildly affected vehicles up to replacement of most brake system components for any vehicle submerged in salt water.

First, inspect all wheel-end components for corrosion and abrasive sediment, including the brake chambers and slack adjusters. Disassemble and clean all brake components, including the air chamber, slack adjuster, cam-tube, S-cam, hardware, and dust shield. Remove and replace shoe and lining assemblies that have been submerged to preempt future rust-jacking.

“Even if brake components do not appear to have been adversely affected by water, test all the systems including the service, emergency and parking brakes for functionality,” says Szudy. “Even the air drier and the compressor should be dismantled, purged of water, inspected and cleaned.”

The control system is another matter, and even more critical. Technicians should check for the presence of water in the brake air system by removing the connectors at the first valve in the system from the front. Inspect the valve for water and contaminants. Use air pressure to blow air through the hoses and watch for evidence of water or contamination. Even if no contamination is found, thoroughly clean the air dryer, and then verify that the parking and emergency brakes apply and release with no perceptible lag.

If water is found, removal of all the water or contamination is not possible without total disassembly of the components. Therefore, Bendix recommends that all pneumatic air brake components be replaced (including the air compressor, air dryer, reservoirs, relay valves, spring-brake valves, ABS relay-modulators, tractor protection valves, and brake actuators).

“The extent of the damage will depend on how long the vehicle remained submerged, but you’re better assuming the worst from a safety perspective,” says Chuck Eberling, principle engineer, advanced engineering and vehicle braking systems at Bendix Commercial Vehicle Systems. “Replacement is necessary to avoid any immediate or future operational issues as a result of internal corrosion and water migration.”

Inside the cab

If the cab became submerged, you have another set of problems on your hands — a possibly uninhabitable environment due to mold or other toxins. The carpets, upholstery, seats and bedding should be at least thoroughly cleaned if not replaced.

“Cushions and upholstery should be cleaned, and HVAC ducts, insulation and vents need to be checked for moisture and mold,” says Mike McHorse, manager, on-highway product marketing, Freightliner Trucks.

Mold could present a health hazard, so it might require professional attention.

Also in the cab are multiple electrical interfaces, breaker panels, and ECUs that would all have to be checked and possibly replaced.

Chances are that if the damage is that bad, the truck will be written off and you won’t have to worry about it. But someone might. Owners of written-off trucks are required to retitle them to “salvage” so they cannot be resold as whole vehicles, but that doesn’t always happen. If you’re buying a used truck in an area with a recent history of flooding, research the vehicle carefully and check for signs that it may have been in a flood.

Equipment rolls through flooded streets in Montreal.

Don’t turn the key

If your truck has been involved in a natural disaster that has resulted in exposure to high water levels or even possible submersion, do not attempt to start the engine or operate the truck. At first glance you will have no idea of the extent of the damage or contamination. The risk is pushing water deeper into various systems than it may be already. In a worst-case scenario, if water has entered the engine through the exhaust or intake system, you could have water in the cylinders. Simply turning the engine over could do major internal damage.

“Our recommendation is to disconnect the batteries immediately to prevent any electrical system from powering up and from someone inadvertently turning over the engine,” says John Crichton, director of field service at Navistar. “Check the air intake system and the turbocharger as well as engine oil and coolant for signs of water egress. Even after all that has been checked, turn the engine over by hand first in case you have any water on top of a piston.”

If it can’t be turned over manually, you’ll have to pull the injectors and disassemble any portion of the engine that water may have seeped into. Along with flood waters also comes sediment, which can be hugely abrasive to bearings and close-tolerance components.

“If there are signs of water inside the engine, you’ll have to inspect the intake and exhaust systems too, including the charge-air cooler, the turbocharger and the emissions systems,” Crichton says. “And then there’s the potential for corrosion. Standing water and condensation begin that process immediately and the longer it sits in there, you start getting rust build up. In the long term, you could have pieces of rusted metal flaking off inside your engine.”

If there’s any possibility water has entered the engine, have it towed to a shop for inspection, first.

What kind of water

Immersion in fresh water or salt water (sea water) will have a very different impact on restoration efforts. Due to the extremely corrosive nature of salt water, many swamped components would simply have to be replaced rather than cleaned and dried as would likely work with fresh-water immersion.

“Salt water changes the equation considerably,” says Chuck Eberling, principle engineer, advanced engineering and vehicle braking systems at Bendix Commercial Vehicle Systems. “Sea water is so highly corrosive to everything on the truck that we pretty well require everything [in the brake system] be replaced.”

Fresh water contamination will initiate corrosion as well, but not quite so severely.

River water, however, often contains sediments and fine particles of dirt swept up in the fast-flowing water. This slurry can be deposited between moving parts like brake components, U-joints, steering linkages, etc., and it can be extremely abrasive.

The other potential problem is water-born toxins or even poisons that may have been introduced if the river inundates a sewage treatment facility, for example, or a chemical dump.

Before you dive in with a pressure washer, make sure you’re not exposing yourself or others to additional and possibly health-threatening contamination.




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Jim Park was a CDL driver and owner-operator from 1978 until 1998, when he began his second career as a trucking journalist. During that career transition, he hosted an overnight radio show on a Hamilton, Ontario radio station and later went on to anchor the trucking news in SiriusXM's Road Dog Trucking channel. Jim is a regular contributor to Today's Trucking and, and produces Focus On and On the Spot test drive videos.

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