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                                                                   Exhibit 4.5.1

                               FIRST AMENDMENT TO
                           LOAN AND SECURITY AGREEMENT

     THIS FIRST AMENDMENT TO LOAN AND SECURITY AGREEMENT (this "Amendment") is
made as of the 25th day of March, 2002 to the Loan and Security Agreement dated
November 28, 2001 (the "Loan Agreement") among Numatics, Incorporated,
Micro-Filtration, Inc., Numation, Inc., Numatech, Inc., Ultra Air Products,
Inc., Microsmith, Inc., Empire Air Systems, Inc. (each a "Borrower" and
collectively "Borrowers") and LaSalle Business Credit, Inc., as Lender and
Collateral Agent. Unless otherwise defined herein, capitalized terms used herein
shall have the meanings ascribed to them in the Loan Agreement.

     WHEREAS, Borrowers have requested that Lender amend the Loan Agreement in
certain respects and Lender has agreed to do so subject to the terms and
conditions hereof.

     NOW, THEREFORE, in consideration of the foregoing, and the mutual covenants
herein contained, and such other consideration as the parties mutually agree,
the parties hereto agree as follows:

          1. Amendment. Borrowers and Lender agree that Section 14(a) of the
     Loan Agreement is amended and restated in its entirety to read as follows:

               (a) Tangible Net Worth.

               Borrowers shall not permit Tangible Net Worth at any time to be
          less than the Minimum Tangible Net Worth; "Minimum Tangible Net Worth"
          being defined for purposes of this subsection as (i) Fifteen Million
          Seven Hundred Thousand and No/100 Dollars ($15,700,000.00) at all
          times from November 28, 2001 through December 30, 2002, (ii) Eighteen
          Million Two Hundred Thousand and No/100 Dollars ($18,200,000.00) at
          all times from and including December 31, 2002 through December 30,
          2003, and (iii) Twenty Million Seven Hundred Thousand and No/100
          Dollars ($20,700,000.00) at all times from and including December 31,
          2003 and thereafter; and "Tangible Net Worth" being defined for
          purposes of this subsection as Numatics' shareholders' equity
          (including retained earnings) on a consolidated basis less the book
          value of all intangible assets and all "Investments", "Other Current
          Assets", "Deferred Tax Assets" and "Other Assets" all as classified on
          Numatics' consolidated balance sheet, including, but not limited to,
          transaction costs not amortized, debt issuance costs not amortized and
          product drawings, as determined solely by Lender on a consistent basis
          less prepaid expenses and obligations due from officers, affiliates
          and employees plus the amount of any LIFO reserve plus the amount of
          any debt subordinated to the Liabilities in a manner satisfactory to
          Lender (but excluding the indebtedness evidenced by the Subordinated
          Redemption Note dated January 3, 2001 in the principal amount of One
          Million Eighty-Nine Thousand Nine Hundred Ninety-Six and

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          No/100 Dollars ($1,089,996.00) issued by Numatics to Bruce W. Hoppe
          and, to the extent in excess of Five Hundred Thousand and No/100
          Dollars ($500,000.00), indebtedness consisting of deferred
          compensation owing to John Welker) plus deferred tax liabilities, all
          as determined for Numatics and its Subsidiaries on a consolidated
          basis under generally accepted accounting principles applied on a
          basis consistent with the financial statement dated September 30, 2001
          except as set forth herein and calculated without giving effect to any
          unrealized non-cash foreign exchange gains and/or losses accumulating
          after December 31, 2001;

          2. Representations and Warranties of Borrowers. Each Borrower
     represents and warrants that, as of the date hereof:

               (a) Each Borrower has the right and power and is duly authorized
          to enter into this Agreement and all other agreements executed in
          connection herewith;

               (b) No Event of Default or an event or condition which upon
          notice, lapse of time or both will constitute an Event of Default has
          occurred and is continuing;

               (c) The execution, delivery and performance by each Borrower of
          this Amendment and the other agreements to which such Borrower is a
          party (i) have been duly authorized by all necessary action on its
          part; (ii) do not and will not, by the lapse of time, giving of notice
          or otherwise, violate the provisions of the terms of its Articles of
          Certificate of Incorporation or By-Laws, or of any mortgage,
          indenture, security agreement, contract, undertaking or other
          agreement to which such Borrower is a party, or which purports to be
          binding on such Borrower or any of its properties; (iii) do not and
          will not, by lapse of time, the giving of notice or otherwise,
          contravene any governmental restriction to which such Borrower or any
          of its properties may be subject; and (iv) do not and will not, except
          as contemplated in the Loan Agreement, result in the imposition of any
          lien, charge, security interest or encumbrance upon any of such
          Borrower's properties under any indenture, mortgage, deed of trust,
          loan or credit agreement or other agreement or instrument to which
          such Borrower is a party or which purports to be binding on such
          Borrower or any of its properties;

               (d) No consent, license, registration or approval of any
          governmental authority, bureau or agency is required in connection
          with the execution, delivery, performance, validity or enforceability
          of this Amendment and the other agreements executed by any Borrower in
          connection herewith;

               (e) This Amendment and the other agreements executed by any
          Borrower in connection herewith have been duly executed and delivered
          by any Borrower and are enforceable against any Borrower in accordance
          with their terms; and

               (f) All information, reports and other papers and data heretofore
          furnished to Lender or Collateral Agent by any Borrower in connection
          with this Amendment, the Loan Agreement and Other Agreements are
          accurate and correct in all material respects and complete

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          insofar as may be necessary to give Lender true and accurate knowledge
          of the subject matter thereof. Each Borrower has disclosed to Lender
          every fact of which it is aware which would reasonably be expected to
          materially and adversely affect the business, operations or financial
          condition of such Borrower or the ability of such Borrower to perform
          its obligations under this Amendment, the Loan Agreement or under any
          of the Other Agreements. None of the information furnished to Lender
          by or on behalf of any Borrower contained any material misstatement of
          fact or omitted to state a material fact or any fact necessary to make
          the statements contained herein or therein not materially misleading.

          3. Conditions Precedent. The amendments to the Loan Agreement set
     forth in this Amendment shall become effective as of the date of this
     Amendment and the following conditions have been satisfied:

               (a) Lender has received a copy of this Amendment executed by each
          party thereto;

               (b) Borrowers have paid Lender a Five Thousand and No/100 Dollar
          ($5,000.00) amendment fee; and

               (c) Lender has received a copy of a fully executed amendment to
          the ACS Purchase Agreement in form and substance satisfactory to
          Lender.

          4. Fees and Expenses. Borrowers agree to pay all legal fees and other
     expenses, whether for in-house or outside counsel, incurred by Lender in
     connection with this Agreement and the transactions contemplated hereby.

          5. Foreign Pledge Agreements. Borrowers agree to execute such
     documents and take such actions as are necessary to grant Lender a valid
     and enforceable first priority security interest in sixty-five percent
     (65%) of the equity in each of Numatics S.A. de C.V., Numatics, Ltd. and
     Numatics S.R.L. by April 30, 2002.

          6. Loan Agreement Remains in Force. Except as specifically amended
     hereby, all of the terms and conditions of the Loan Agreement shall remain
     in full force and effect and this Agreement shall not be a waiver of any
     rights or remedies which Lender has provided for in the Loan Agreement and
     all such terms and conditions are herewith ratified, adopted, approved and
     accepted.

          7. No Novation. This Amendment and all other agreements executed by
     Borrowers on the date hereof are not intended to nor shall be construed to
     create a novation or accord and satisfaction, and shall only be a
     modification and extension of the existing Liabilities of Borrowers to
     Lender.

          8. Entire Agreement. This Amendment and the other documents it refers
     to comprise the entire agreement relating to the subject matter they cover
     and supersede any and all prior written or oral agreements among Lender and
     Borrowers relating thereto.

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          9. Severability. Any provision of this Amendment that is prohibited or
     unenforceable in any jurisdiction shall, as to such jurisdiction, be
     ineffective to the extent of such prohibition or unenforceability without
     invalidating the remaining provisions hereof or affecting the validity or
     enforceability of such provision in any other jurisdiction.

          Except as expressly provided for herein, the terms and conditions of
     the Loan Agreement shall remain in full force and effect.

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     IN WITNESS WHEREOF, Borrowers and Lender have caused this Amendment to be
duly executed by their proper duly authorized officers oaf the day and year
first set forth above.

                                                LASALLE BUSINESS CREDIT, INC.


                                                By  /s/ Dale P. Grzenia
                                                    ---------------------------
                                                Its   Vice President
                                                    ---------------------------

                                                NUMATICS, INCORPORATED
                                                MICRO-FILTRATION, INC.
                                                NUMATION, INC.
                                                NUMATECH, INC.
                                                ULTRA AIR PRODUCTS, INC.
                                                MICROSMITH, INC.
                                                EMPIRE AIR SYSTEMS, INC.


                                                Each By /s/ Robert P. Robeson
                                                        -----------------------
                                                Their    Secretary
                                                        -----------------------

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