WASHINGTON--Senators threatened with a disrupted vacation overwhelmingly adopted President Bush's savings and loan rescue after bowing to a last-minute plea to strengthen a key reform.

Dwarfing all other government bailouts, the plan approved yesterday would provide at least $157 billion over the next decade--most of it from taxpayers--to close or merge 350 failed thrift institutions and make good on government pledges in the rescue of 200 others last year.

It would also reorganize the regulatory bureaucracy, provide $50 million a year for the Justice Department to pursue fraud in S&Ls and enact other reforms, chief among them a requirement that thrift owners back their lending with more of their own capital.

The ultimate passage of the bill was never in doubt, but Sen. Howard M. Metzenbaum (D-Ohio) was threatening to prolong debate, which began Monday, into the weekend unless senators agreed to tougher capital requirements.

Sen. Donald W. Riegle Jr. (D-Mich.) chair of the Senate Banking Committee, and Sen. Jake Garn (R-Utah), the panel's senior Republican, had been resisting amendments, arguing that the package put together privately by the committee and endorsed by a 21-0 vote last week was too delicately balanced to with-stand many changes without crumbling.

But only five minutes before the scheduled start of an 11-day recess, Metzenbaum succeeded in wresting concessions that allowed senators to adopt the bill, 91-8, and leave town until May 1.

The committee's bill had doubled capital standards, requiring S&L owners to come up with $6 for every $100 in lending, compared with the current requirement of $3.

However, it provided a big loophole for about a third of the nation's 3,000 S&Ls by allowing an accounting item known as "good will" to be counted as capital for the next 25 years. Good will represents the value of an institution's customer loyalty and other intangible assets.

Declaring that "goodwill isn't worth doodly-doo," Metzenbaum insisted that S&Ls have at least 1.5 percent in "tangible capital"--cash, stocks and property that could easily be converted to cash and could be seized, in the event of a failure, before turning to government deposit insurance funds.

Metzenbaum had sought 3 percent tangible capital but in the end had to accept 1.5 percent. Regulators will have the authority to restrict the growth of institutions falling below that level.

"I can't say I'm satisfied with the result that has been obtained," he said, adding, "I can say substantive progress has been made," Metzenbaum said.

Treasury Secretary Nicholas F. Brady praised the bill, saying, "[We] applaud the Senate's efforts to maintain strong capital requirements."

Metzenbaum was urged on by two groups--Consumer Federation of America and Consumers Union--that decided to emphasize capital as an important consumer issue. The groups are hoping the Metzenbaum victory will lend momentum to their fight to toughen the House version of the S&L bill.

The House Banking subcommittee on financial institutions passed a similar 1.5 percent standard last week and Rep. Henry B. Gonzalez (D-Texas), chair of the full committee, says he will try to increase that when his panel begins redrafting the legislation next Wednesday.