This is an appeal from a judgment allowing a claim in bankruptcy. A brief statement of the background may be helpful in understanding the manner in which the questions for determination arise. In 1935, M. E. Heiser sued Leonard J. Wood-ruff and others in the United States Coun for Southern California. It was alleged in the complaint that plaintiff had been and was engaged in the business of mining and marketing raw gems, particularly emeralds, sapphires, and zircons; that in 1928, he arrived in the United States from Australia on a business trip to find and establish a regular and ready market for raw gems, mined under his control and management in Australia; that he then owned and had in California certain sapphires, opals, zircons, and jade; that such gems were reasonably worth $164,000; and that the defendants cheated and defrauded him out of them. The defendant Woodruff failed to answer or otherwise plead in the case; plaintiff submitted evidence; and on March 20, 1939, the court entered judgment against such defendant for $164,000, together with accrued interest, aggregating $277,036.71. The defendant filed a motion to set aside the judgment. The motion was denied. The parties stipulated that the court might hear evidence respecting the value of the property of plaintiff for which damages were awarded in the judgment; and that should the court find the value to be less than the amount of the judgment, the judgment should be modified and reduced to the amount which represented the value of the property. On June 29, 1939, after hearing evidence, the court found the value of the property to be the amount fixed in the judgment.
Woodruff filed in the United States Court for Eastern Oklahoma his voluntary petition in bankruptcy; and, on July 5, 1939, an order of adjudication was entered. Heiser filed in the proceeding an unsecured claim, based upon the judgment. The referee entered an order authorizing any creditor of the estate to contest any claim filed. Willie Mae Woodruff, wife of the bankrupt, and Ida Belle Woodruff, as creditors, filed objections to the claim of Heiser; and the bankrupt also filed objections. The referee authorized the trustee to employ an attorney in California and take such legal steps as seemed necessary and proper to vacate the judgment. The trustee and Woodruff filed in the cause in California a joint motion to vacate the judgment, vacate the default, vacate the orders entered after the rendition of the judgment, permit Woodruff to answer, and permit the trustee to intervene. The court denied the motion, Woodruff and the trustee appealed, and the order wás affirmed. Jackson v. Heiser, 9 Cir., 111 F.2d 310. The referee later heard evidence and disallowed the claim in toto; on review, the district court entered judgment allowing it in full; and by order, the court authorized the objecting creditors to appeal from the judgment.
The action of the district court in allowing the claim was predicated upon the conclusion that the proceedings in California constituted res judicata of the matters set up in the objections. Section 2 of the Bankruptcy Act, as amended, 52 Stat. 840, 11 U.S.C.A. § 11, provides among other things that the district courts sitting in bankruptcy shall be vested with such jurisdiction in law and in equity as will enable them to exercise original jurisdiction in proceedings under the act; and that they may make such orders and enter such judgments, in addition to those specifically provided for, as may be necessary for the enforcement of the provisions of the act. A court of bankruptcy is essentially a court of equity, and its proceedings are inherently proceedings in equity. It exercises equitable powers of wide sweep in relation to problems arising out of the administration of bankrupt estates; and, with appropriate regard for rights acquired under the law of the state, its equitable powers may be exerted in full vigor with respect to the allowance of claims, the rejection of claims, or the subordination of claims to other claims. Pepper v. Litton, 308 U.S. 295, 60 S.Ct. 238, 84 L.Ed. 281; Prudence Realization Corporation v. Geist, 316 U.S. 89, 62 S.Ct. 978, 86 L.Ed. 1293.
A bankruptcy court in which an estate is being administered has full power to inquire into the validity of an alleged debt of the bankrupt upon which a claim against the estate is based. And the merger of the original debt or obligation *871into judgment does not take away the power of the bankruptcy court to inquire into its provability. Notwithstanding the change in form of the liability from a simple contract debt, or an unliquidated claim, into a judgment of a court of record, it remains the same debt and the bankruptcy court may look behind the judgment to determine the essential nature of the liability for purposes of proof and allowance or rejection. Pepper v. Litton, supra. And in the absence of a well grounded plea of res judicata, the trustee in bankruptcy may collaterally attack a judgment which is presented as a claim against the estate on the ground that it was founded upon no real debt of the bankrupt. Pepper v. Litton, supra.
The claim of Heiser was contested on the grounds that no personal service of summons was had upon the defendant Woodruff in the action in California; that the complaint filed in the action failed to state a cause of action under the laws of California; that the complaint showed on its face that if plaintiff ever had any cause of action, it was barred by the statutes of limitation of California; and that the judgment was void for the reason that the complaint undertook to state three separate and distinct causes of action and the judgment failed to specify the cause upon which it was rendered. By the motion to vacate the judgment, set aside the default, vacate the orders entered after the rendition of the judgment, and permit the interposition of a defense to the action, the trustee and the defendant Woodruff expressly attacked the judgment on these grounds, and others. The trustee was acting for all of the creditors of the estate of the bankrupt, and the determination of such issues adverse to him constitutes res judicata here to that extent and protects the judgment against collateral attack on those grounds. Pepper v. Litton, supra.
But the grounds of contest did not end there. It was specifically charged in the objections that at the time of the filing of the suit in California and at the time of the rendition of the judgment, Woodruff was not indebted to Heiser in any amount; that the material allegations contained in the complaint were untrue; that the judgment was obtained through the use of perjured testimony given by Heiser; and that Heiser thus committed a fraud upon the court and the parties. The record fails to indicate that these matters were placed before the court in California, either in the motion of the defendant Woodruff to vacate the judgment, by the motion of the trustee and the defendant Woodruff to set aside the judgment, or otherwise. Therefore the judgment did not constitute res judicata in respect of these issues, and the claim was open to attack on these grounds. Pepper v. Litton, supra. In reaching this conclusion we are mindful of the statement in Jackson v. Heiser, supra, that the charge of fraud in obtaining the judgment was denied, not proved, and apparently abandoned. But the nature of the fraud referred to does not appear. And the record before us does not contain any showing that the contention that the material allegations in the complaint were knowingly false, that the judgment was secured through the use of perjured testimony given by Heiser, and that a fraud thus was committed on the court and the parties was ever submitted to the court in California by motion to vacate the judgment or otherwise, or that such issues were ever expressly adjudicated by that court in fav- or of Heiser.
The evidence concerning the claim was extensive and presented issues of fact. But the court did not make any formal findings of fact or conclusions of law. It was the duty of the court to make findings and conclusions, in accordance with Federal Rule of Civil Procedure 52(a), 28 U.S.C.A. following section 723c. And where the issues cannot be decided satisfactorily on appeal without findings of fact by the trial court, the judgment may be vacated and the cause remanded in order that findings of fact may be made. Mayo v. Lakeland Highlands Canning Co., 309 U.S. 310, 60 S.Ct. 517, 84 L.Ed. 774; Kelley v. Everglades Drainage District, 319 U.S. 415, 63 S.Ct. 1141, 87 L.Ed. 1485.
Where the trial court embodied in its written opinion specific findings on the material issues of fact and set out conclusions on the important questions of law involved, the cause should not be remanded for formal findings and conclusions. Carter Coal Co. v. Litz, 4 Cir., 140 F.2d 934. The court rendered an opinion in writing, but it does not present the findings or conclusions of the court upon the issues open to inquiry concerning the debt or obligation underlying the judgment. And the issues can not be satisfactorily decided on appeal without findings of fact.
*872The provision in the judgment allowing the claim of Heiser is vacated, and the cause is remanded for appropriate action in conformity with this opinion.