How do I properly escape '=' in my string replacement script?

I have made a batch script that replaces strings in a specified text-based file. Within my file, the string OutDir=bin should be replaced as OutDir=Build but gets output as bin=OutDir=Build=bin. How do I escape the = in OutDir=bin so that the string doesn't become garbled? I have tried OutDir^= but using the carrot doesn't work either.

Here is my current script:

@echo off     setlocal enableextensions disabledelayedexpansion    set search=OutDir=bin    set replace=OutDir=Build    set textFile=%DOCUMENT%.txt    for /f "delims=" %%i in ('type "%textFile%" ^& break ^> "%textFile%"') do (        set "line=%%i"        setlocal enabledelayedexpansion>>"%textFile%" echo(!line:%search%=%replace%!        endlocal    )

I have attempted to change the find and replace variables to compensate for the = in the string I'm replacing but none have worked:

set search= "OutDir=bin"set replace= "OutDir=Build"set search="OutDir=bin"set replace="OutDir=Build"set "search=OutDir=bin"set "replace=OutDir=Build""set search=OutDir=bin""set replace=OutDir=Build"