LEHMER'S CONCORD BUICK GMC | SERVING DE LA SALLE AND CARONDELET FAMILIES AND OUR COMMUNITY SINCE 1928. Lehmer's is proud to be the Official GMC truck supplier for the Spartans. Whether you are looking to purchase a new or used car or need auto service, we invite you to experience our family-owned, fifth generation state-of-the-art facility and award-winning hospitality in Concord. We are the Bay Area's oldest franchised General Motors dealership and we are a proud Spartan family. Go Spartans! Tammy and Rick Freeman ('86) [email protected], Darren Anderson (’89) [email protected]