SOUTHFIELD, Mich. — Ford Motor Co., struggling to overcome record losses this year, plans to borrow as much as $18 billion to pay for American job cuts and factory shutdowns and will back its loans with collateral for the first time.

The new chief executive officer, Alan Mulally, must raise cash to revamp the North American auto unit as he works to boost sales and recover from a $6.99 billion loss in the first nine months of the year. Ford’s switch to asset-backed loans is a sign investors are demanding protection from a default.

“It significantly raises the total debt burden, and it massively increases the amount of secured debt,” the chief of New York-based research firm Credit-Sights Inc., Glenn Reynolds, said. “There’s still very low default risk, but bondholders’ asset protection has been significantly eaten into.”

About $15 billion of the new debt will be secured by collateral, Ford said in a statement. An $8 billion secured credit line will replace an unsecured $6.3 billion loan. The Dearborn, Mich.-based company also plans a new $7 billion secured term loan and $3 billion in unsecured funding, which may include notes that can be converted into equity shares.

American automakers’ domestic sales are falling as buyers abandon light trucks for more fuel-efficient passenger cars by rivals such as Toyota Motor Corp. The industry’s decline has pushed five major auto-parts makers into bankruptcy since February 2005.

For collateral, Ford is using American plants, other American automotive assets, and “all or a portion” of profitable units such as Ford Motor Credit Co. and Volvo. JPMorgan Chase & Co., Citigroup Inc., and Goldman Sachs Group Inc. are arranging the financing, which will be completed by December 31, Ford said.

Moody’s Investors Service, Standard & Poor’s, and Fitch Ratings all cut Ford’s unsecured debt rating yesterday, citing less protection for investors in case of a default. Fitch rates the debt B, five steps below investment grade; the Moody’s rating of Caa1 and S&P’s CCC+ rating are seven steps below.

Ford’s 7.45% note due in 2031 fell 0.75 cent from November 22 to 78.75 cents on the dollar, yielding 9.7%, according to Trace, the NASD’s bondprice reporting service.

The company had $154 billion in debt outstanding as of September 30, at least $130 billion of which was issued by the finance unit.

Ford’s North American auto unit has lost money in eight of the past nine quarters, and the automaker’s share of the American new-vehicle market will decline for the 11th consecutive year in 2006. Ford now says the North American unit will become profitable in 2009, one year later than a target set in January.

They realize they’re in worse shape than they thought and it’s going to take a long time to fix this,”a Montclair, N.J.-based debt analyst at Gimme Credit Publications, Shelly Lombard, said.

“This subordinates the bonds, but the alternative — running out of cash and filing bankruptcy — is worse,” she said.