1
                                                                     EXHIBIT 5.1


                             [FLOWSERVE LETTERHEAD]


September 19, 2000



Flowserve Corporation
222 West Las Colinas Boulevard
Suite 1500
Irving, Texas  75039

Dear Sirs:

With reference to the registration statement on Form S-8 which Flowserve
Corporation (the "Company") proposes to file with the Securities and Exchange
Commission (the "SEC") under the Securities Act of 1933, registering 3,400,000
shares of common stock, par value $1.25 per share, of the Company (the "Shares")
which may be offered and sold by the Company under the Flowserve Corporation
1997 Stock Option Plan and the Flowserve Corporation 1999 Stock Option Plan, I
am of the opinion that:

     1. the Company is a corporation duly organized, validly existing and in
good standing under the laws of the State of New York, and

     2. all proper corporate proceedings have been taken so that any Shares to
be offered and sold which are of original issuance, upon sale and payment
therefor in accordance with the Plans and the resolutions of the Board of
Directors relating to the offering and sale of the Shares thereunder, will be
legally issued, fully paid and non-assessable.

I hereby consent to the filing of this opinion with the SEC in connection with
the registration statement referred to above.


                                            Very truly yours,


                                            /s/ Ronald F. Shuff

                                            Ronald F. Shuff
                                            Vice President, Secretary and
                                            General Counsel