UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549





FORM 10-K/A

(Amendment No. 1)





ANNUAL REPORT
PURSUANT TO SECTION 13 OR- 15(d) OF

THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2011

Commission File Number 1-898





AMPCO-PITTSBURGH CORPORATION



|                                                  |  |                                
|------------------------------------------------- |  | -------------------------------
|Pennsylvania                                      |  | 25-1117717                     
|(State of Incorporation)                          |  | I.R.S. Employer ID No.         
|                                                  | 
|600 Grant Street, Suite 4600 Pittsburgh, PA 15219 |  | (412) 456-4400                 
|(Address of principal executive offices)          |  | (Registrants telephone number)

Securities registered pursuant to Section 12(b) of the Act:



|                           |  |                                          
|-------------------------- |  | -----------------------------------------
|Title of each class        |  | Name of each exchange on which registered
|Common stock, $1 par value |  | New York Stock Exchange                  

Securities registered pursuant to Section 12(g) of the Act:  None





Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities
Act.    Yes   ̈    No  þ

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes   ̈    No  þ

Indicate by
check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to
file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  þ    No   ̈

Indicate by check mark whether the Registrant has submitted electronically and posted on its
corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T(§232.405 of this chapter) during the preceding 12 months (or such shorter period that the registrant was required
to submit and post such files).    Yes  þ    No   ̈

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained,
to the best of Registrants knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  þ

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or smaller
reporting company. See the definitions of large accelerated filer, accelerated filer and smaller reporting company in Rule 12b-2 of the Exchange Act.



|                        |  |   |  |                           |  |  
|----------------------- |  | - |  | ------------------------- |  | -
|Large accelerated filer |  |  ̈ |  | Accelerated filer         |  | þ
|                        |  |   | 
|Non-accelerated filer   |  |  ̈ |  | Smaller reporting company |  |  ̈

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange
Act).    Yes   ̈    No  þ

The aggregate market value of the voting stock of Ampco-Pittsburgh Corporation held by non-affiliates on June 30, 2011 (based upon the closing price of the Registrants Common Stock on the New
York Stock Exchange (the NYSE) on that date) was approximately $199 million.

As of March 12, 2012, 10,331,436 common shares
were outstanding.

Documents Incorporated by Reference: Part III of this report incorporates by reference certain information from the Proxy
Statement for the 2012 Annual Meeting of Shareholders.









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EXPLANATORY NOTE

Ampco-Pittsburgh Corporation (the Company) is filing this Amendment No. 1 (this Amendment) to its Annual
Report on Form 10-K for the fiscal year ended December 31, 2011, filed with the Securities and Exchange Commission on March 15, 2012 (the Original Report), for the sole purpose of correcting an error in Item 9A, Controls
and Procedures. In the first sentence of the second paragraph under the subheading Managements Annual Report on Internal Control Over Financial Reporting, the Company inadvertently referred to December 31, 2010 as the date as
of which management assessed the effectiveness of the Companys internal control over financial reporting. In fact, management assessed the effectiveness of the Companys internal control over financial reporting as of December 31,
2011. The Company is filing this Amendment solely to amend Item 9A to clarify the date as of which management assessed the effectiveness of the Companys internal control over financial reporting. This Amendment amends and restates in
their entirety Item 9A of Part II and Item 15 of Part IV of the Original Report.

No other amendments,
modifications, updates or changes are being made to the Original Report other than as described above. This Amendment speaks as of the date of the filing of the Original Report. The Company has not taken into account any other events occurring after
the filing of the Original Report which might have affected any disclosures in the Original Report, nor has the Company amended, modified, updated or otherwise changed any disclosures to reflect any subsequent events.

We have also included as exhibits the certifications required under Section 302 of The Sarbanes-Oxley Act of 2002. Because no
financial statements are contained within this Amendment, we are not including certifications pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.



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ITEM 9A. CONTROLS AND PROCEDURES

Disclosure Controls and Procedures. An evaluation of the effectiveness of the Corporations disclosure controls and procedures as of the end of the period covered by this report was carried
out under the supervision, and with the participation, of management, including the principal executive officer and principal financial officer. Disclosure controls and procedures are defined under Securities and Exchange Commission
(SEC) rules as controls and other procedures that are designed to ensure that information required to be disclosed by a company in the reports that it files under the Exchange Act is recorded, processed, summarized and reported within
required time periods. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by an issuer in the reports that it files or submits under the Exchange Act
is accumulated and communicated to the issuers management, including its principal executive and principal financial officers, or persons performing similar functions, as appropriate, to allow timely decisions regarding required disclosure.
Based on that evaluation, the Corporations management, including the principal executive officer and principal financial officer, has concluded that the Corporations disclosure controls and procedures were effective at the reasonable
assurance level as of December 31, 2011.

Managements Annual Report on Internal Control Over Financial Reporting. The
Corporations management is responsible for establishing and maintaining adequate internal control over financial reporting (as defined in Rule 13a  15(f) under the Securities Exchange Act of 1934, as amended). Internal control over
financial reporting cannot provide absolute assurance of achieving financial reporting objectives because of its inherent limitations. Effective internal control over financial reporting can only provide reasonable assurance that the objectives of
the control process are met. Internal control over financial reporting is a process that involves human diligence and compliance and is subject to lapses in judgment and breakdowns resulting from human failures. Internal control over financial
reporting also can be circumvented by collusion or improper management override. Because of such limitations, there is a risk that material misstatements may not be prevented or detected on a timely basis by internal control over financial
reporting. However, these inherent limitations are known features of the financial reporting process. Therefore it is possible to design into the process safeguards to reduce, though not eliminate, this risk. Further, the design of internal control
over financial reporting includes the consideration of the benefits of each control relative to the cost of the control.

Management assessed
the effectiveness of internal control over financial reporting as of December 31, 2011. In making this assessment, management used the criteria set forth in Internal Control  Integrated Framework issued by the Committee of Sponsoring
Organizations of the Treadway Commission. Based on those criteria and managements assessment, management, including the principal executive officer and principal financial officer, concluded that the Corporations internal control over
financial reporting was effective as of December 31, 2011.

The Corporations independent registered public accounting firm,
Deloitte & Touche LLP, has issued an attestation report on the Corporations internal control over financial reporting which is included herein.

Changes in Internal Control Over Financial Reporting. There were no changes in the Corporations internal control over financial reporting during the quarter ended December 31, 2011 that
have materially affected, or are reasonably likely to materially affect, its internal control over financial reporting.



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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Directors and Shareholders of Ampco-Pittsburgh Corporation

We have audited the internal control over financial reporting of Ampco-Pittsburgh Corporation and subsidiaries (the Corporation) as of December 31, 2011, based on criteria established in
Internal Control  Integrated Frameworkissued by the Committee of Sponsoring Organizations of the Treadway Commission. The Corporations management is responsible for maintaining effective internal control over financial reporting
and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Managements Annual Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the
Corporations internal control over financial reporting based on our audit.

We conducted our audit in accordance with the standards of
the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material
respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the
assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A companys internal control over financial reporting is a process designed by, or under the supervision of, the companys principal executive and principal financial officers, or persons
performing similar functions, and effected by the companys board of directors, management, and other personnel to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for
external purposes in accordance with generally accepted accounting principles. A companys internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable
detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with
generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding
prevention or timely detection of unauthorized acquisition, use, or disposition of the companys assets that could have a material effect on the financial statements.

Because of the inherent limitations of internal control over financial reporting, including the possibility of collusion or improper management override of controls, material misstatements due to error or
fraud may not be prevented or detected on a timely basis. Also, projections of any evaluation of the effectiveness of the internal control over financial reporting to future periods are subject to the risk that the controls may become inadequate
because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

In our opinion, the
Corporation maintained, in all material respects, effective internal control over financial reporting as of December 31, 2011, based on the criteria established in Internal Control  Integrated Frameworkissued by the Committee of
Sponsoring Organizations of the Treadway Commission.

We have also audited, in accordance with the standards of the Public Company Accounting
Oversight Board (United States), the consolidated financial statements as of and for the year ended December 31, 2011 of the Corporation and our report dated March 15, 2012 expressed an unqualified opinion on those financial statements.



LOGO

Pittsburgh, Pennsylvania

March 15, 2012



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 PART IV 

ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

THE FOLLOWING DOCUMENTS ARE
FILED AS PART OF THIS REPORT:



|1. | Financial Statements
|-- | --------------------

 Consolidated
Balance Sheets

 Consolidated Statements of Operations

 Consolidated Statements of Shareholders Equity

 Consolidated Statements of
Cash Flow

 Notes to Consolidated Financial Statements

 Report of Independent Registered Public Accounting Firm



|2. | Financial Statement Schedules
|-- | -----------------------------

The
following additional financial data should be read in conjunction with the consolidated financial statements in this Annual Report on Form 10-K. Schedules not included with this additional financial data have been omitted because they are not
applicable or the required information is shown in the financial statements or notes thereto.



|                                                        |  |                |    |  |            |  |    | 
|------------------------------------------------------- |  | -------------- | -- |  | ---------- |  | -- | 
|                                                        |  | ScheduleNumber |    |  | PageNumber | 
|Index to Ampco-Pittsburgh Corporation Financial Data    |  |                |    |  |            |  | 68 | 
|Report of Independent Registered Public Accounting Firm |  |                |    |  |            |  | 69 | 
|Valuation and Qualifying Accounts                       |  |                | II |  |            |  | 70 | 



|3. | Exhibits
|-- | --------

Exhibit No.



|(3) | Articles of Incorporation and By-laws
|--- | -------------------------------------



| | a. | Articles of Incorporation
| | -- | -------------------------

Incorporated by reference to the Quarterly Report on Form 10-Q for the quarter ended March 31, 1983; the Quarterly Report on Form
10-Q for the quarter ended March 31, 1984; the Quarterly Report on Form 10-Q for the quarter ended March 31, 1985; the Quarterly Report on Form 10-Q for the quarter ended March 31, 1987; and the Quarterly Report on Form 10-Q for the
quarter ended September 30, 1998.



| | b. | By-laws
| | -- | -------

Incorporated by
reference to the Form 8-K dated December 21, 2010.



|(10) | Material Contracts
|---- | ------------------



| | a. | 1988 Supplemental Executive Retirement Plan, as amended and restated December 17, 2008 Incorporated by reference to the 2008 Annual Report on Form 10-K.
| | -- | --------------------------------------------------------------------------------------------------------------------------------------------------------



| | b. | Severance Agreements between Ampco-Pittsburgh Corporation and certain officers and employees of Ampco-Pittsburgh Corporation as amended and restated December 31,
2008 Incorporated by reference to the 2008 Annual Report on Form 10-K.
| | -- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | c. | Amendment to Severance Agreement between Ampco-Pittsburgh Corporation and Robert A. Paul dated February 16, 2011 Incorporated by reference to the 2010 Annual
Report on Form 10-K.
| | -- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | d. | 2008 Omnibus Incentive Plan Incorporated by reference to the Proxy Statement dated March 6, 2008.
| | -- | -------------------------------------------------------------------------------------------------



| | e. | 2011 Omnibus Incentive Plan Incorporated by reference to the Proxy Statement dated March 22, 2011.
| | -- | --------------------------------------------------------------------------------------------------



| | f. | Retirement and Consulting Agreement between Ampco-Pittsburgh Corporation and Ernest G. Siddons dated April 30, 2009 Incorporated by reference to the Quarterly
Report on Form 10-Q for the quarter ended March 31, 2009.
| | -- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



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|       |  |                                                                                                                                                                                                  
|------ |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|       | 
|(21)   |  | Significant Subsidiaries
Incorporated by reference to the 2011 Annual Report on Form 10-K filed on March 15, 2012.                                                                               
|       | 
|(23.1) |  | Consent of Deloitte & Touche LLP Incorporated by reference to the 2011 Annual Report on Form 10-K filed on March 15, 2012.                                                                       
|       | 
|(23.2) |  | Consent of Hamilton, Rabinovitz & Associates, Inc. Incorporated by reference to the 2011 Annual Report on Form 10-K filed on March 15, 2012.                                                     
|       | 
|(31.1) |  | Certification of Principal Executive Officer pursuant to Section 302 of The Sarbanes-Oxley Act of 2002.
Incorporated by reference to the 2011 Annual Report on Form 10-K filed on March 15, 2012.
|       | 
|(31.2) |  | Certification of Principal Financial Officer pursuant to Section 302 of The Sarbanes-Oxley Act of 2002.
Incorporated by reference to the 2011 Annual Report on Form 10-K filed on March 15, 2012.
|       | 
|(31.3) |  | Certification of Principal Executive Officer pursuant to Section 302 of The Sarbanes-Oxley Act of 2002.                                                                                          
|       | 
|(31.4) |  | Certification of Principal Financial Officer pursuant to Section 302 of The Sarbanes-Oxley Act of 2002.                                                                                          
|       | 
|(32.1) |  | Certification of Principal Executive Officer pursuant to Section 906 of The Sarbanes-Oxley Act of 2002.
Incorporated by reference to the 2011 Annual Report on Form 10-K filed on March 15, 2012.
|       | 
|(32.2) |  | Certification of Principal Financial Officer pursuant to Section 906 of The Sarbanes-Oxley Act of 2002.
Incorporated by reference to the 2011 Annual Report on Form 10-K filed on March 15, 2012.
|       | 
|(101)  |  | Interactive Data File (XBRL) Incorporated by reference to the 2011 Annual Report on Form 10-K filed on March 15, 2012.                                                                           



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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly
authorized.



|                |  |  |  |                              |  |                               
|--------------- |  |  |  | ---------------------------- |  | ------------------------------
|August 22, 2012 |  |  |  | AMPCO-PITTSBURGH CORPORATION
|                |  |  | 
|                |  |  |  | By:                          |  | /s/ Robert A. Paul            
|                |  |  |  |                              |  | Name: Robert A. Paul          
|                |  |  |  |                              |  | Title: Chief Executive Officer



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