can you file bankruptcy just to buy more time on a foreclosure?

Well, the way you phrase your question leaves open a lot of possible answers and without more specific facts it's hard to be accurate.   Filing a bankruptcy case will (assuming it's the first case filed in the last year) stop a foreclosure sale temporarily.  But how long depends on a whole host of factors, such as what chapter you file, what other debts there are, whether you're seeking to catch up on payments on the property in question, how much equity it has, what other assets you have, etc.  If you have no intention to complete a bankruptcy or pay the lender, and this is your only (or primary) debt, then it would likely be considered a bad faith filing and your case will be dismissed within a couple of months.  The lender may also seek relief from the automatic stay sooner to proceed with the foreclosure.  Mark Markus has been practicing exclusively bankruptcy law in California since 1991.  He is a Certified Specialist in Bankruptcy Law by the State Bar of California Board of Legal Specialization,  AV-Rated by martindale.com, and A+ rated by the Better Business Bureau.