These nine consolidated appeals are from the orders of the lower court granting appellees’ motions for summary judgment. In each case, an appellant brought a wrongful death and survival action grounded in negligence, strict liability in tort, and breach of warranty against appellees, asbestos companies, for asbestos-related injuries suffered by a decedent.1 Appellees then filed motions for summary judgment alleging that the appellant’s causes of action were barred by the applicable statutes of limitations. In orders dated November 27, 1984.2 and January 1, 1985,3 the lower court granted appellees’ motions for summary judgment in each case and dismissed appellants’ complaints with prejudice. Appellants contend on appeal that the lower court erred in finding that their complaints were time-barred. We affirm in part, reverse in part, and remand for further proceedings.
The lower court held that appellants’ complaints were untimely filed under the rule announced by our Supreme Court in Anthony v. Koppers Co., Inc., 496 Pa. 119, 436 A.2d 181 (1981). In Anthony, the Supreme Court considered and rejected the application of the “discovery rule”4 to the statutes of limitations then in effect for *169wrongful death and survival actions, and held that the limitations periods began to run, at the latest, on the date of the decedent’s death.
The statutes of limitation considered in Anthony provided a one-year period from the date of death in which to bring wrongful death actions, 12 P.S. § 1603, and a two-year period “from the time when the injury was done” for bringing survival actions. Id. § 34. Both statutes were repealed by the Judiciary Act Repealer Act of April 28, 1978, P.L. 202, § 2a (310) (wrongful death), (807) (survival), effective June 27, 1978, and have been recodified at 42 Pa.C.S.A. § 5524(2).5 In the recodification, both forms of action have a two-year statute of limitations. Id.
In the instant cases, the lower court applied the old statutes of limitations and found that each decedent had died more than two years before the filing of the complaint. See Appendix. For that reason, it held that all of the complaints were time-barred.
Appellants first contend that the lower court erred in applying Anthony retroactively to complaints brought before that decision was filed on October 29, 1981. We disagree.
In Pennsylvania, judicial decisions are normally retroactive, and the construction placed by the court upon a statute becomes part of the act from the very beginning. ____ A court’s interpretation will be applied to cases arising from the time of the enactment of the statute unless vested rights are affected.
Baker v. Casualty and Surety Co., 309 Pa. Superior Ct. 81, 85-86, 454 A.2d 1092, 1094-95 (1982) (citations omitted). *170See also August v. Stasak, 492 Pa. 550, 554, 424 A.2d 1328, 1330 (1981). When deciding whether a decision should be applied prospectively only, we consider three factors:
“First, the decision to be applied nonretroactively must establish a new principle of law, either by overruling clear past precedent on which litigants may have relied ... or by deciding an issue of first impression whose resolution was not clearly foreshadowed____ Second, it has been stressed that ‘we must ... weigh the merits and demerits in each case by looking to the prior history of the rule in question, its purpose and effect, and whether retrospective operation will further or retard its operation.’ ... Finally, [the courts] have weighed the inequity imposed by retroactive application, for ‘[w]here a decision ... could produce substantial inequitable results if applied retroactively, there is ample basis in [the case-law] for avoiding the “injustice or hardship” by holding of nonretroactivity.’ ”
Fairbanks v. Travelers Insurance Co., 337 Pa. Superior Ct. 39, 42, 486 A.2d 469, 470 (1984) (quoting Chevron Oil Co. v. Huson, 404 U.S. 97, 106-07, 92 S.Ct. 349, 355, 30 L.Ed.2d 296 (1971) (citations omitted)). The first factor of the Chevron test, whether the decision establishes a new principle of law, is a threshold factor that must be met before the other two factors are considered. See Schreiber v. Republic Intermodal Corp., 473 Pa. 614, 622, 375 A.2d 1285, 1289 (1977); Baker v. Aetna Casualty and Surety Co., supra, 309 Pa.Superior Ct. at 89 n. 9, 454 A.2d at 1096 n. 9.
After reviewing our Supreme Court’s decision in Anthony, we find that it does not meet the threshold test of Chevron. The statutes of limitations at issue in Anthony were enacted in 1855 (wrongful death) and 1895 (survival) and had been applied since their enactment without applying the discovery rule. In Anthony, therefore, our Supreme Court declined to create a new legal principle and, instead, reaffirmed the traditional application of the statutes of limitations for wrongful death and survival actions.
*171Appellants argue, nevertheless, that a new principle of law was established in Anthony because its result was not “clearly foreshadowed.”6 They argue that the decision was contrary to the trend towards extending the application of the discovery rule to statutes of limitations in a variety of situations. We believe that the existence of such a trend is irrelevant where, as in Anthony, the plain language of the statutes clearly precluded the application of the discovery rule. See Anthony v. Koppers Co., Inc., supra 496 Pa. at 123, 125, 436 A.2d at 183, 184-85; Gravinese v. Johns-Manville Corp., 324 Pa. Superior Ct. 432, 439, 471 A.2d 1233, 1237 (1984). Having found that Anthony did not establish a new legal principle, and thus failed to meet the threshold requirement of the Chevron test, we hold that the lower court did not err in applying its holding retroactively.7 Cf. Gravinese v. Johns-Manville Corp., supra (applying Anthony retroactively without discussion).
Appellants next contend that the discovery rule should toll the statute of limitations for all wrongful death and tort survival actions filed after June 27, 1978, the effective date of the recodified statute of limitations, 42 Pa.C.S.A. § 5524(2). Appellants argue that (1) the discovery rule applies to § 5524(2) and (2) that section governs all complaints filed after its effective date. While this Court has held, in accordance with appellants' first argument, that the discovery rule is applicable to § 5524(2), see Pastierik v. Duquesne Light Co., 341 Pa. Superior Ct. 329, 491 A.2d 841 (1985), we cannot agree that the new statute of limitations applies to all wrongful death and tort survival *172actions filed after its effective date. The Judicial Code states: “No cause of action fully barred prior to the effective date of this act shall be revived by reason of the enactment of this act.” Judiciary Act of July 9, 1976, P.L. 586, No. 142, § 25(G) (reprinted following 42 Pa.C.S.A. § 5524). Thus, in Symbula v. Johns-Manville Corp., 343 Pa. Superior Ct. 541, 495 A.2d 598 (1985), we held that the discovery rule will operate to toll the new statute of limitations for wrongful death and tort survival actions, but only
where the action is commenced after the effective date of the Judicial Code statute of limitations, and the decedent’s date of death was on or after June 26, 1977, with regard to wrongful death actions [where 12 P.S. § 1603 had previously supplied a one-year statute of limitations], and on or after June 26, 1976, with regard to survival actions [where 12 P.S. § 34 had previously provided for a two-year period]____
Id., 343 Pa.Superior Ct. at 545, 495 A.2d at 600.
Applying these principles to the instant cases, we find that the discovery rule is applicable only to two of the appeals before us. In No. 246 PHL 85, James Simpkins died on May 2, 1977, and the complaint on behalf of his estate was filed on November 5, 1980. See Appendix. Therefore, the discovery rule applies to appellant Simp-kins’s tort survival claim, but not the wrongful death action. In No. 247 PHL 85, Clark Stephens died on January 21, 1978, and the complaint on behalf of his estate was also filed on November 5, 1980. See id. Thus, the discovery rule applies to both appellant Stephens’s wrongful death and tort survival claims. The causes of action of the remainder of appellants were time-barred before the effective date of § 5524(2). Accordingly, we will reverse the order of the lower court, dated January 10, 1985, insofar as it granted summary judgment to appellees and dismissed the tort survival action in No. 246 PHL 85 and the wrongful death and tort survival claims in No. 247 PHL 85.8
*173Appellants Simpkins and Stephens, Nos. 246 and 247 PHL 85, respectively, also contend that the lower court erred in dismissing their breach of warranty survival claims.9 The Uniform Commercial Code provides a four-year statute of limitations for breach of warranty actions. 13 Pa.C.S.A. § 2725 (formerly 12A P.S. § 2-725). See also Williams v. West Penn Power Co., 502 Pa. 557, 467 A.2d 811 (1983) (four-year statute of limitations applies to personal injury claims founded upon breach of warranty).10 Here, the actions in both the Simpkins’s case and the Stephens’s case were brought within four years of the date of the decedent’s death. See Appendix. We therefore reverse the order of the lower court dismissing as time-barred the survival claims for breach of warranty contained in Nos. 246 and 247 PHL 85.11
Finally, appellants contend that the allegations in their complaints that appellees intentionally and negligently concealed facts giving rise to the instant causes of action, if proven, would estop appellees from invoking the bar of the statute of limitations.
*174“Mere mistake, misunderstanding or lack of knowledge is not sufficient to toll the running of the statute.” Shaffer v. Larzelere, 410 Pa. 402, 405, 189 A.2d 267, 269 (1963); McNair v. Weikers, ... 300 Pa. Superior Ct. [379,] 388, 446 A.2d [905,] 909 [ (1982) ]. It is only where the defendant, through fraud or concealment, causes the plaintiff to relax his or her vigilance or to deviate from the right of inquiry that a defendant is estopped from invoking the bar of the statute of limitations. ... In general, this requires that a defendant have done something amounting to an affirmative inducement to plaintiff to delay bringing the action. ... The party asserting estoppel, moreover, has the burden of proving fraud by evidence that is clear, precise and convincing.
Gravinese v. Johns-Manville Corp., supra, 324 Pa. Superior Ct. at 441-42, 471 A.2d at 1238 (citations omitted). As in Gravinese, we find nothing in the record here that would create an issue of concealment sufficient to estop appellees from asserting a statute of limitations defense. See id.; see also Symbula v. Johns-Manville Corp., supra, 343 Pa. Superior Ct. at 546 n. 6, 495 A.2d at 601 n. 6. We therefore find this issue meritless.
For the foregoing reasons, we affirm the orders of the lower court on appeals Nos. 3372 and 3373 PHL 84 and Nos. 245, 248-250, and 252 PHL 85; reverse the lower court’s dismissal of the survival actions in tort and breach of warranty in Nos. 246 and 247 PHL 85, and its dismissal of the wrongful death action in No. 247 PHL 85; and remand for further proceedings consistent with this opinion. Jurisdiction is not retained.
APPENDIX
Name of Appellant Date of and Docket No._ Death Date Suit Years Filed Delay
MARIE MIHALCIK, Admx. 8/26/74 1/27/81 6½
of the Estate of
ANDREW MIHALCIK, et al. 3372 PHL 1984
*175Name of Appellant Date of Date Suit and Docket No. Death Filed Years Delay
HELEN PETACCIO, Ex. of 12/9/75 the Estate of ARMAND PETACCIO, et al. 3373 PHL 1984 11/17/80 5
MARION DORSEY STEWART, 1/28/74 Admx. of the Estate of DAVID DORSEY, et al. 245 PHL 1985 11/5/80 7
ELOISE SIMPKINS, Admx. 5/2/77 of the Estate of JAMES SIMPKINS, et al. 246 PHL 1985 11/5/80 3V2
BERNICE STEPHENS, Admx. 1/21/78 of the Estate of CLARK STEPHENS, JR. 247 PHL 1985 11/5/80 3
RONALD MAYKUT, Ex. 8/7/75 of the Estate of WALTER MAYKUT 248 PHL 1985 4/8/81 51/2
CATHERINE WRIGHT, Admx. 11/27/70 of the Estate of CHARLES WRIGHT 249 PHL 1985 5/1/81 10/2
LOUISE BRUNO, Admx. of 4/12/59 the Estate of AUGUSTINE BRUNO 250 PHL 1985 5/29/81 22
MARILYN BILLIOPS, Admx. 11/7/74 of the Estate of ROBERT KELLY 252 PHL 1985 11/20/80 6