Jan 20 (Reuters) - Auto-parts supplier Checker Motors Corp, which used to make the iconic Checker taxi cab, filed for bankruptcy protection, citing high labor and raw material costs, as well as weak sales due to a decline in its customers' market share.

The Kalamazoo, Michigan-based company filed for Chapter 11 bankruptcy protection in a U.S. bankruptcy court in Michigan on Friday, and said it expects to restructure itself to respond to changes in the auto industry.

Checker, established by Morris Markin in 1922 through a merger of Commonwealth Motors and Markin Automobile Body, had assets worth about $24.5 million and liabilities of about $21.8 million as of Nov. 30, 2008, the court papers showed.

The company, which employs about 246 people, said it had aimed to restructure voluntarily without resorting to bankruptcy and had been seeking to negotiate a concessionary labor agreement with its union for about a year.

Checker plans to "reorganize its business and to bring its labor costs in-line with other similarly situated automotive suppliers," it said in the filing.

Several auto suppliers have filed for bankruptcy protection in recent months as the Detroit Big Three automakers have scaled back their output due to a slump in sales.

Checker, which stopped making its famous yellow taxi cabs in 1982, now manufactures stamped components and welded assemblies. Its customers include General Motors Corp (GM.N: Quote, Profile, Research), Ford Motor Co (F.N: Quote, Profile, Research) and Chrysler LLC, according to its website.

The case is In re Checker Motors Corp, No 09-00358, U.S. Bankruptcy Court, Western District of Michigan. (Reporting by Santosh Nadgir in Bangalore; Editing by Aradhana Aravindan and Pratish Narayanan)