Striking mechanics in the Chicago area voted to continue their work stoppage Saturday, rejecting a new deal that would have ended their nearly-two week work stoppage.

Nearly 2000 members of Automobile Mechanics Union Local 701 have been on strike since Aug. 1, affecting nearly 180 car dealerships in the Chicago area.

According to reports, the main sticking point in negotiations involves benefits for employees. According to the Chicago Tribune, a dispute over billable hours is also to blame, as mechanics say that they’re often working for free while they’re on the clock, because of manufacturer limits on the number of hours certain jobs take.

Lawyers for car dealers say that deal can go the other way as well, with mechanics getting paid for an hour of work when a repair only takes a half hour to complete.

The New Car Dealer Committee, which is representing dealers in Chicago, engaged in a marathon negotiating session on Thursday with the mechanic’s union before presenting its latest offer. The membership of the union voted on the new proposal Saturday and rejected it.

Nearly half of all new car dealers in the Chicago area have unionized mechanics, and according to the Tribune there are no mixed shops that feature both unionized and non-unionized workers.