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Rock-splatter skirting protects maintenance trucks, saves almost $22K

Rocks were spraying from the road, kicked up by snowplow blades, breaking and damaging ITD’s engine belts in District 2 Maintenance trucks at an alarming rate. These rocks then got between the engine belts and pulleys, causing belt damage and putting the truck out of service. The problem was forcing the district to replace belts at least every two weeks.

At more than $70 per belt, it was adding up quickly. Last spring, Roy Hill, a TSEA in District 2 Maintenance (pictured below), decided to do something about this $29,000 problem. Hill was then the Shop Supervisor, so he got to see every truck with a damaged belt as each limped in to be fixed.

“It was an inconvenience that became a big problem,” said Hill. “I spent about four or five months to come up with a solution, and had to go back to the drawing board several times before we arrived at a final product.”

He developed an 11-inch “anti-spray skirt” that mounted to the rear of the plow harness, directly below the radiator. Finding a solution was difficult because the hydraulic pumps were front-mounted, and all of the hoses and controller wiring had to pass through the area — but the exact location of this was not uniform on many of the trucks. However, the skirt solution allowed each individual truck to have the same fix without modifying the barrier, since the skirt fits around hoses and wiring.

The skirting is similar to the type of anti-spray skirt made for semitrailers, meant to keep road spray from “boiling” up around the wheel wells during rainy weather, Hill said.

“It is made from nylon with a multitude of nylon fingers all 11 inches long. The nylon fingers can part around an object, but are still fairly rigid,” he explained.

A solid deflector was impractical because the exact location where the hydraulic hoses ran to the rear of the plow truck from the front-mounted pump varied from unit to unit.

“Using this skirting allowed us to make up the number of skirts needed and install the exact same skirt on each unit. The skirting would then self-form around the hydraulic hoses, wherever they were located. This made for a one-type-fits-all solution, saving time and making installation on our entire fleet practical,” he added.

The skirting does not totally eliminate the problem, but has been successful in deflecting a majority of rocks. They now only have to replace belts damaged by airborne rocks once or twice per season.

The $29,000 problem has been reduced to $7,000.

District 2’s local Mack dealer (these were Mack 10-wheeled trucks) heard of the innovation and passed it on, along with pictures of the spray skirt, to the Washington State Department of Transportation. The agency had encountered similar issues. Pictures are shown to the right.