In 1922, a group of investors constructed a building in Harrisburg, PA to house the leaf spring operations of Harrisburg Stanley Spring Works. By the year 1927, Benjamin Franklin Barker was installed as President and General Manager in an effort to make the operation profitable. Unfortunately, the depression of the 20's and early 30's forced that corporation into bankruptcy in 1934.

In 1935, Frank and Rhoda Barker formed a new corporation named Stanley Spring Works, Inc. After WWII, the federal government had a tremendous surplus of leaf springs. Barker was able to purchase thousands of tons of this surplus, which he resold at a substantial profit which enabled the business to invest in new equipment and manufacture a quality product.

In 1954, Angelo Paioletti was promoted to vice president. Stanley Spring Works then began to build a substantial inventory of finished goods. With high quality product and inventory now available, Barker and Paioletti changed Stanley's marketing strategy from selling primarily to the automotive parts houses to selling exclusively to spring service shops and export markets. This proved to be highly successful. With growing recognition in the industry, Stanley Spring Works expanded its marketing territory to include the deep south and west to the Mississippi River.

The most significant change in the company came in 1964, when Frank Barker sold controlling interest in the business to five of his employees: Angelo Paioletti, Edwin Musser, Charles Orris, Charles Haring and John Stengel.

Under the guidance of new management, Stanley Spring Works more than doubled its rate of growth. They quickly reached the position of second in the country in replacement leaf spring sales and first in quality. A trend in facility expansion continued between 1969 and 1974.

With the great success of Stanley Spring Works, many large corporations began to court the company. Stanley Spring Works was sold to TRW in 1981 and became TRW Heavy Duty Parts. The company then became Dayton Parts, Inc. in 1988 when Varity Corporation combined TRW Heavy Duty Parts and Dayton Walther's aftermarket.

In 1992, JPE, Inc. acquired Dayton Parts, Inc. and in 1997 Dayton Parts, Inc. acquired Brake, Axle and Tandem Company (BATCO), who was an industry leader in foundation air brake and wheel attaching components. In May of 1999, ASC Holdings, LLC acquired controlling interest in JPE, Inc.  In February 2003, the management team and Gen Cap of America became financial partners and acquired the business, forming Dayton Parts, LLC.  January of 2006, management recapitalized the business with Capital Partners and continued to focus on high service levels for the heavy, medium and light duty truck Independent Aftermarket.  

In February of 2007, Dayton Parts, LLC acquired S&G Enterprises and Merion Spring Company (a subsidiary of S&G).  Then in May of 2012, the management team of Dayton Parts, LLC partnered with AEA Investors, LP to purchase Dayton Parts, LLC to continue and expand on the growth of Dayton Parts, LLC.  Under the new partnership, one of the first acquisitions Dayton Parts, LLC was to purchase Dallas Spring / Eagle Suspension.  Dallas Spring is a leading distributor of leaf springs and suspension components servicing the heavy-duty aftermarket and Eagle Suspension is a leading manufacturer of leaf springs to some of the most respected truck, trailer and suspension system builders in the world.  The transaction closed in November of 2012.