William Agee, chairman of Bendix Corp., yesterday signed a hasty truce with RCA Corp., pledging not to buy any more of its stock for at least 30 days and repeating a promise not to attempt a takeover.

After a day of conversations by attorneys from both sides, Bendix issued a statement saying it would maintain its present holdings of 5.5 million shares of RCA, about 7.3 percent of total shares outstanding. Further, Bendix said it would declare formally to the Securities and Exchange Commission that it has "no intention to acquire any additional shares of RCA stock."

Although Agee had insisted this week that Bendix's surprising purchase of RCA stock was solely for investment purposes, RCA saw a sinister motive, attacking the "secret accumulation" of its shares and making a blistering personal assault on Agee.

In its initial announcement Mondy, Bendix said it has acquired somewhat more than 5 percent of RCA's stock, indicating it might continue buying until it reached 9.9 percent. (Purchases above that level could lead to government antitrust scrutiny of Bendix's intentions.)

The Bendix statement yesterday freezes its position, ending for now the speculation about what lay in store for RCA, the electronics and communications giant whose depressed sales and stock price had made it a prime takeover target in the view of many market analysts.

Bendix and RCA officials would not discuss the communications that produced yesterday's statements. Agee and RCA Chairman Thornton F. Bradshaw apparently did not talk yesterday, according to an RCA spokesman. "The lawyers worked it out," the RCA official said.

Among Bradshaw's moves Monday was the retention of the law firm Wachtell, Lipton, Rose & Katz, specialists in hard-nosed defenses against hostile corporate takeovers, and they may have made it plain to Agee's representatives that RCA's counter measures would be stiff and unpleasant, one source close to the situation speculated yesterday.

RCA's statement Monday focused on Agee personally, charging that "his only purpose is to further his own ambitions." That ferocity probably surprised Agee--in any case, attorneys for both sides evidently decided the matter had gotten out of hand.

The statements yesterday were full of sweetness and light. RCA "expressed its appreciation of Bendix's confirmation of its status as an investor and the confidence expressed in the future of RCA."

In addition to a promise not to buy more RCA stock for 30 days, Bendix said that if it changes its mind thereafter and decides to obtain more stock, it will notify RCA 48 hours in advance. Bendix "reemphasized its aims were to acquire a significant investment in RCA on friendly terms since it considers RCA to be an excellent value at current market prices" and "believes the RCA investment has good prospects to become a profitable part of its portfolio. . . . Bendix reiterated that it has no plans for an acquisition, merger or reorganization of RCA," the Bendix statement said.

Despite such assurances, some industry analysts assumed that Agee's long-term goal was to obtain enough stock to exert influence over RCA's management, perhaps compelling RCA to exchange some of its subsidiaries for the Bendix-owned stock. Maurice Valente, who headed RCA for six months in 1980, told The New York Times that RCA's parts--"NBC, Hertz, consumer electronics--are worth much more separately than the $1.5 billion market value of the whole company. NBC alone could bring a good portion of that."

An acquisitions strategy would threaten RCA directly, however, because Agee has said he will move Bendix into new high-technology enterprises, while Bradshaw wants to use RCA's technology base to rebuild the company.