5 tips for fire apparatus suspension care

Here's a look at what every fire apparatus driver needs to know about maintaining and inspecting the rig's suspension system

Once upon a time, a firefighter was doing daily checks on the fire engine they were assigned to drive and operate that day. While checking the fuel level and water level in the tank, the firefighter saw something unusual on the frame rail while “under the hood.”

After wiping the area clean to get a better look, the firefighter saw that there was a crack in the frame rail about 4 to 5 inches long. The firefighter reported this to their company officer, who immediately placed the engine out of service and reported this action to their battalion chief. Ultimately, the engine never returned to service.

A work of fiction? No. It happened in my former organization and it’s what should happen in every department.

Now don’t get me wrong; I’m not negating the need for regular annual inspections for fire apparatus by a certified EVT. Nor am I dismissing the need for an EVT to examine a fire apparatus to determine if the rig can or should remain in service.

But who is better than the firefighter who drives the apparatus on a regular basis to know what’s right or what’s wrong with their apparatus?

And who better than that firefighter’s company officer, who also knows the apparatus in question, to make the call to take the unit out of service?

As in professional sports, that judgement call by the company officer can be reversed upon further review by an EVT if it was not the right call. In our business, it’s better to err on the side of caution.

Apparatus care responsibility

We’re talking about empowerment. Before empowerment can take place, a department’s leadership must ensure that there are proper policies and procedures in place and that everyone is fully trained on those documents. Because with empowerment comes responsibility.

One tip I heard from a couple of EVTs is to use a mechanic’s creeper to get under the rig and photograph all the key suspension and chassis components. Or accompany your apparatus the next time it goes to the repair shop and get those photos while the rig is up on the lift.

Either way, those photographs will form the baseline of what everything looked like before something went wrong or broke. As part of the monthly maintenance and inspection, have the firefighter and officer examine all those photographed areas to see if there’s been any change.

Why both the firefighter and their officer? Because two sets of eyes are better than one; the officer needs to be just as familiar with the apparatus as his or her people; and it’s a good opportunity for some one-on-one time between the supervisor and their direct report.

That last item may be the most important, because trust in working relationships is more easily developed by working through jobs or tasks together.

Working side-by-side with their firefighter during an apparatus check can be one small thing that leads to bigger dividends down the road — like when that firefighter goes to the officer and says, “Captain, we’ve got a pretty good sized crack in the engine’s frame rail.”

Whether your department has a daily apparatus check process or not, here are five keys points that the operator should be checking during daily operational and post-fire checks to ensure the undercarriage is in good shape.

1. Apparatus Vehicle stance

Start by looking at the big picture. Check the overall appearance of vehicle stance to ensure it’s not leaning to one side or the other.

2. Weight distribution

Ensure that the load is evenly distributed so that the suspension system and apparatus chassis can work the way they were designed. One EVT reported seeing apparatus out of balance by as much as 1,000 pounds from one side to the other.

Who hasn’t seen this happen one piece of equipment at a time? A shift wants equipment X on one side for easier access. C shift found something in a storage closet that they wanted to carry on the apparatus. Before you know it, the rig is listing like a ship taking on water.

3. Tire damage

Look for cuts in the tire’s sidewall that penetrate to the cord, bulges greater than 3⁄8 of an inch or sidewall separation. Tires with even the slightest edge wear, cupping or spotty wear are exhibiting signs of misalignment.

This misalignment may be a result of either poor alignment settings or worn parts that create a misaligned front suspension.

4. Tire pressure

Ensure that tire pressures are maintained to the specifications of the tire manufacturer. Under-inflated tires can cause a poor ride since properly inflated tires are part of the engineering that went into the design of the suspension system. Under-inflated tires also wear out quicker and unevenly.

5. Tread depth

Check tire tread depth monthly using three points on tire: the 10, 2 and 6 o’clock positions. On those three points, measure the tread depth on the outside edge, middle and inside edge of the tire. You’re right, that adds up to nine measurements for each tire.

Fire apparatus should be removed from service if you find any tread depth measurements less than 4/32 of an inch on any steering axle or less than 2/32 of an inch on any non-steering axle.

Daily fire apparatus inspection and maintenance should include a good look at what’s under the apparatus as well. It doesn’t have to be as in-depth as the monthly examination, but a quick scan of the rig’s underbelly can identify those problems that stick out like a sore thumb.

  • Examine the front suspension for damaged rims or improper mounting, missing leaf springs or cracks in leaves, damage to shock absorbers or struts and mounting hardware and damaged or loose tie rods.
  • Examine the undercarriage for loose bolts, hanging wires, leaks, broken parts, debris in the components and any damage to the drive train, body mounts or cross members.
  • Examine the rear suspension for damaged rims or improper mounting, missing leaf springs or cracks in leaves and fluid leaks from the differential.

Apparatus Driving observations

Pay attention to how your vehicle handles. As a truck’s suspension system goes bad, steering can require more physical effort, tires can wiggle and the steering wheel can feel like it has a mind of its own.

The issue most obviously related to a vehicle’s suspension is bumpy driving. A properly working suspension system smooths out the ride, even when a vehicle is going down an uneven road.

But as the suspension fails, a vehicle’s bounce becomes more violent. Don’t look for your fire truck to hop up and down like a low-rider on flat surfaces, just that bumps get more noticeable.

The suspension system does more than keep all the tires on the ground at the same time. It’s also crucial for keeping the vehicle going in a straight line. If you are constantly pulling the wheel from one side to the other, it’s likely an indication that something is wrong somewhere in the suspension system. 

Even one of these issues can cause plenty of trouble if not addressed early. So pay close attention to how your truck responds to your commands.

And when it stops consistently meeting your expectations, take it to your nearest EVT for them to get it back on track. 

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