Last year’s mild winter and the economic slowdown are still affecting sales of replacement parts at Genuine Parts Co. in Atlanta.

Thomas Gallagher, Genuine Parts’ chairman and CEO, said Thursday that the company was seeing a slowdown in global demand from some equipment and machinery customers. Sales of car brakes and windshield wipers were slower than expected in the Central U.S., Midwest and Northeast in the third quarter of the year, the result of the relatively warm winter.

“We were a bit disappointed in the sales results in each of our core businesses,” Gallagher said in a conference call.

Gallagher speculated that consumers were deciding to spend more of their discretionary income on electronics and back-to-school purchases, rather than non-critical car repairs. Overall vehicle replacement parts sales were softer than expected at the beginning of the quarter, said Paul Donahue, the company’s president.

A more normal winter should drive some of those sales back, he said.

Across the company’s business, though, the slowdowns have been inconsistent. While solar and contract manufacturing have been challenged, iron and steel, chemicals and wire and cable have been strong, Gallagher said.

Across all businesses, sales are expected to increase between 6 and 7 percent in the fourth quarter, Gallagher said. Genuine Parts made $172.9 million in the quarter, a 13.9 percent increase over the same period in 2011.