Many House Democrats yesterday threatened to try to hold up final action on President Reagan's budget cuts to force restoration of the Social Security minimum benefit now received by 3 million Americans.

Even as House and Senate conferees were giving formal approval to nearly $36 billion in spending cuts, House Rules Committee Chairman Richad Bolling (D-Mo.) said he was considering a strategy to force deletion fot ehminimum benefit repealer from the huge budget "reconciliation" bill.

Noting that Reagan pledged in a nationwide television address to protect the benefits of those who are dependent on Social Security Bolling said. "The only way to make an honest man of him is to knock out that provision of the [reconciliation] conference report."

Bolling's comments came as more than 125 House members, including mostly Democrats but some Republicans as well, cosponsored a resolution calling on House conferees on the reconciliation bill to strike out previously approved language that would kill the $122-month-a-month minimum benefit for current and future recipients.

At the same time, Democrats on the Rules Committee agreed informally in a caucus to try to hold up a vote on the reconciliation measure until a separate vote can be taken on the minimum-benefit issue.

"There are all kinds of things we can do, including simply not having a meeting" to clear the bill, Bolling said.

Reaffirming votes taken earlier by both chambers, the reconciliation conferees voted to end the minimum benefit for future recipients in December and for those now receiving it in March, thereby saving about $1 billion next year and as much as $7 billion over the next five years.

With thousands of elderly people demonstrating on the Capitol steps, the House voted overwhelmingly last week to seek restoration of the benefits for those now receiving it, although not necessarily in the reconciliation conference agreement.

The Republican-controlled Senate rejected a proposal to restore the benefit by way of a rider to Reagan's tax-cut legislation. But Senate GOP leaders subsequently joined House leaders of both parties in saying they intend to work for legislation that would at least soften the impact of the benefit's repeal.

However, budget leaders consistently hve opposed reopening the massive package of spending cuts out of fear that such action might unravel the delicate bipartisan understandings that paved the way for smooth completion of the conference.

The resolution sponsored in the House by Rep. Bruce F. Vento (D-Minn.) has been forwarded to the Rules Committee for consideration at a meeting that had been planned for today to clear the way for House action on the reconciliation bill Friday.

In addition to calling on the conferees to go back and rescue the minimum benefits, the resolution would prohibit consideration of any reconciliation conference report that reduces the minimum benefit before the second session of the 97th Congress, which begins in January.

Formal approval by the conferees of the spending cuts legislation came after the last of several loose ends were tied up yesterday morning, including new provisions for charging interest on loans to states to cover unemployment insurance costs.

"It's clear to me, without any doubt, that this Congress has succeeded in the single most heroic effort at controlling federal spending in the nation's history," said Senate Budget Committee Chairman Pete V. Domenici (R.-N.M.) at a signing ceremony.

But Democratic liberals were not so jubilant. "Now I know how the Japanese felt when they signed the instruments of surrender on the battleship Missouri," said Rep. Stephen J. Solarz (D-N.Y.) as he signed the papers, holding his nose.