When William von Raab was commissioner of the Customs Service he frequently met with members of Congress on subjects ranging from drug enforcement to his agency's budget.

The only time he was asked "to do something I thought was wrong," von Raab said, was when three lawmakers requested that he drop a complaint that a candidate for an ambassadorship had smuggled watches into the country. "I felt a little soiled as a result. But I didn't feel it was improper because they didn't have any leverage over me. . . . They couldn't take money from my budget."

That is one key difference between his experience and that of Edwin J. Gray, former chairman of the Federal Home Loan Bank Board, a main witness in the Senate ethics committee's hearings on the intervention of five senators on behalf of savings and loan executive Charles H. Keating Jr.

Gray testified this week that he felt intimidated at a 1987 meeting with the senators because he considered them vital in winning approval of legislation to replenish the depleted insurance fund for the savings and loan industry.

The question of how far members of Congress should go in contacting federal regulatory officials on behalf of constituents who are campaign contributors is a central issue in the ethics investigation of the "Keating Five." The senators -- Alan Cranston (D-Calif.), Dennis DeConcini (D-Ariz.), John Glenn (D-Ohio), John McCain (R-Ariz.) and Donald W. Riegle Jr. (D-Mich.) -- have defended their 1987 meetings with Gray and his subordinates on Keating's behalf as normal constituent service.

A number of former Reagan administration regulatory officials who were interviewed this week agreed with von Raab that congressional requests for such meetings for a specific company or individual were rare, but did happen.

"I'm not sure it's {intervention for constituents} an appropriate part of their job, but it has been and is a part of their job," said von Raab, who headed the Customs Service from 1981 to 1989. "And if the committee determines it's not, it will make a fundamental change in the relationships between members of Congress and the executive branch.

"It is a very real check on the executive branch. . . . The real monitoring I had on my activities was my committee hearings and my inquiries from the Hill."

In opening statements last week, DeConcini likened the Keating case to his efforts on behalf of Arizona farmers to get the Interior Department to modify regulations about the cost of water from reclamation projects. Cranston said if the committee decides it is improper to take action for someone who has made a legal political contribution, as Keating did, "then every senator . . . had better run for cover -- because every senator has done it, every senator must do it."

The St. Petersburg Times reported last April that even after the publicity about the Keating intervention, bank regulators received requests from several senators and their aides for leniency on banks in their states. In another case, Rep. Glenn M. Anderson (D-Calif.) inquired in 1986 about a rejected application for a bank charter for a group that included his wife. His opponent tried to make the case an issue in this year's election, but Anderson said he did not do anything he would not do for another constituent.

Earlier this year, Sen. Bob Packwood (R-Ore.) called Carol Hallett, the current head of the Customs Service, to his office to protest a ruling that meant higher import duties on athletic shoes made by Oregon-based Nike. A Packwood spokeswoman said the senator "occasionally" requests such meetings with regulators.

L. William Seidman, head of the Federal Deposit Insurance Corp., another banking agency, said in an affidavit in the Keating hearing that he had never attended a meeting like the one to which the senators summoned Gray. A spokesman for the Federal Reserve Board, which also regulates some banks, said such requests are "extremely rare."

John A. Pendergrass, former administrator of the Occupational Safety and Health Administration, said he had only one memorable congressional contact, a phone call at home from a senator who was "unhappy" about an OSHA action.

"I was a little put out by the call. The senator wasn't well informed and I thought he was trying to interfere with the operations of the agency," Pendergrass said. Pendergrass said he took no action, the senator -- whom he declined to name -- never called again, and he could not remember whether the complaint was that OSHA was too tough or not tough enough.

William D. Ruckelshaus, who was head of the Environmental Protection Agency when it was started in 1970 in the Nixon administration and again during the Reagan administration, said it was common for members of Congress to inquire about the agency's treatment of a city or state government permit. There were only a few times members made requests he considered improper.

"I always treated inquiries I thought were borderline as if the caller didn't know," he said. "I would say the case was under administrative review, and if he continued talking I would have to consider it an ex parte communication and have to take notes for the record of the case. Usually that was enough. I can only think of a couple of times where that occurred. I don't recall I ever had to get up and walk out of a meeting with a member of Congress because I thought it was wrong."

Like Ruckelshaus, James L. Miller III, former chairman of the Federal Trade Commission, said he had a "set spiel" when a lawmaker called about a specific case the commission was considering. "I'd say, 'Well, you must be calling on the merits, not politics. And I'll have to put on the record any communications.' They would usually be sort of flabbergasted and that would usually be enough." He recalled only one instance where a legislator was not deterred by that caution.

Daniel Oliver, another former FTC chairman, and David S. Ruder, former chairman of the Securities and Exchange Commission, said they had few telephone inquiries from members of Congress and no requests for meetings about particular cases. Ruder said he was following the hearings in the Keating case and said "I regarded it as highly unusual to have even a single senator come to me. To have five come would have seemed extraordinary."