diff --git a/src/util.rs b/src/util.rs
index 12b0ea58..0ceb133a 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -70,3 +70,31 @@ impl<'a, R: Reader> Reader for RefMutReader<'a, R>
         self.inner.read(buf)
     }
 }
+
+/// Additional integer write methods for a io::Read
+pub trait WriteIntExt {
+    /// Write a u32 in little-endian mode
+    fn write_le_u32(&mut self, u32) -> io::Result<()>;
+    /// Write a u16 in little-endian mode
+    fn write_le_u16(&mut self, u16) -> io::Result<()>;
+}
+
+impl<W: Write> WriteIntExt for W {
+    fn write_le_u32(&mut self, val: u32) -> io::Result<()> {
+        let mut buf = [0u8; 4];
+        let v = val;
+        buf[0] = ((v >>  0) & 0xFF) as u8;
+        buf[1] = ((v >>  8) & 0xFF) as u8;
+        buf[2] = ((v >> 16) & 0xFF) as u8;
+        buf[3] = ((v >> 24) & 0xFF) as u8;
+        self.write_all(&buf)
+    }
+
+    fn write_le_u16(&mut self, val: u16) -> io::Result<()> {
+        let mut buf = [0u8; 2];
+        let v = val;
+        buf[0] = ((v >>  0) & 0xFF) as u8;
+        buf[1] = ((v >>  8) & 0xFF) as u8;
+        self.write_all(&buf)
+    }
+}
diff --git a/src/writer.rs b/src/writer.rs
index b873b0d9..af1c4521 100644
--- a/src/writer.rs
+++ b/src/writer.rs
@@ -6,7 +6,6 @@ use crc32;
 use result::{ZipResult, ZipError};
 use std::default::Default;
 use std::io;
-use std::io::Seek;
 use std::io::prelude::*;
 use std::old_io::Writer;
 use std::mem;
@@ -64,7 +63,7 @@ struct ZipWriterStats
     bytes_written: u64,
 }
 
-impl<W: Write+Seek> Write for ZipWriter<W>
+impl<W: Write+io::Seek> Write for ZipWriter<W>
 {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize>
     {
@@ -98,7 +97,7 @@ impl ZipWriterStats
     }
 }
 
-impl<W: Write+Seek> ZipWriter<W>
+impl<W: Write+io::Seek> ZipWriter<W>
 {
     /// Initializes the ZipWriter.
     ///
@@ -135,9 +134,7 @@ impl<W: Write+Seek> ZipWriter<W>
                 header_start: header_start,
                 data_start: 0,
             };
-            let mut conv_w = IoConverter::new(writer);
-            try!(writer_spec::write_local_file_header(&mut conv_w, &file));
-            let writer = conv_w.into_inner();
+            try!(writer_spec::write_local_file_header(writer, &file));
 
             let header_end = try!(writer.seek(io::SeekFrom::Current(0)));
             self.stats.start = header_end;
@@ -168,9 +165,7 @@ impl<W: Write+Seek> ZipWriter<W>
         file.uncompressed_size = self.stats.bytes_written;
         file.compressed_size = try!(writer.seek(io::SeekFrom::Current(0))) - self.stats.start;
 
-        let mut conv_w = IoConverter::new(writer);
-        try!(writer_spec::update_local_file_header(&mut conv_w, file));
-        let writer = conv_w.into_inner();
+        try!(writer_spec::update_local_file_header(writer, file));
         try!(writer.seek(io::SeekFrom::End(0)));
         Ok(())
     }
@@ -194,12 +189,10 @@ impl<W: Write+Seek> ZipWriter<W>
             let writer = self.inner.get_plain();
 
             let central_start = try!(writer.seek(io::SeekFrom::Current(0)));
-            let mut conv_w = IoConverter::new(writer);
             for file in self.files.iter()
             {
-                try!(writer_spec::write_central_directory_header(&mut conv_w, file));
+                try!(writer_spec::write_central_directory_header(writer, file));
             }
-            let writer = conv_w.into_inner();
             let central_size = try!(writer.seek(io::SeekFrom::Current(0))) - central_start;
 
             let footer = spec::CentralDirectoryEnd
@@ -221,7 +214,7 @@ impl<W: Write+Seek> ZipWriter<W>
 }
 
 #[unsafe_destructor]
-impl<W: Write+Seek> Drop for ZipWriter<W>
+impl<W: Write+io::Seek> Drop for ZipWriter<W>
 {
     fn drop(&mut self)
     {
@@ -234,7 +227,7 @@ impl<W: Write+Seek> Drop for ZipWriter<W>
     }
 }
 
-impl<W: Write+Seek> GenericZipWriter<W>
+impl<W: Write+io::Seek> GenericZipWriter<W>
 {
     fn switch_to(&mut self, compression: CompressionMethod) -> ZipResult<()>
     {
diff --git a/src/writer_spec.rs b/src/writer_spec.rs
index 2827fc5a..62e2540b 100644
--- a/src/writer_spec.rs
+++ b/src/writer_spec.rs
@@ -1,12 +1,13 @@
-use std::old_io;
+use std::io;
 use std::io::prelude::*;
 use std::ascii::AsciiExt;
 use types::ZipFile;
 use result::ZipResult;
 use spec;
 use util;
+use util::WriteIntExt;
 
-pub fn write_local_file_header<T: Writer>(writer: &mut T, file: &ZipFile) -> ZipResult<()>
+pub fn write_local_file_header<T: Write>(writer: &mut T, file: &ZipFile) -> ZipResult<()>
 {
     try!(writer.write_le_u32(spec::LOCAL_FILE_HEADER_SIGNATURE));
     try!(writer.write_le_u16(20));
@@ -27,17 +28,17 @@ pub fn write_local_file_header<T: Writer>(writer: &mut T, file: &ZipFile) -> Zip
     Ok(())
 }
 
-pub fn update_local_file_header<T: Writer+Seek>(writer: &mut T, file: &ZipFile) -> ZipResult<()>
+pub fn update_local_file_header<T: Write+io::Seek>(writer: &mut T, file: &ZipFile) -> ZipResult<()>
 {
-    static CRC32_OFFSET : i64 = 14;
-    try!(writer.seek(file.header_start as i64 + CRC32_OFFSET, old_io::SeekSet));
+    static CRC32_OFFSET : u64 = 14;
+    try!(writer.seek(io::SeekFrom::Start(file.header_start + CRC32_OFFSET)));
     try!(writer.write_le_u32(file.crc32));
     try!(writer.write_le_u32(file.compressed_size as u32));
     try!(writer.write_le_u32(file.uncompressed_size as u32));
     Ok(())
 }
 
-pub fn write_central_directory_header<T: Writer>(writer: &mut T, file: &ZipFile) -> ZipResult<()>
+pub fn write_central_directory_header<T: Write>(writer: &mut T, file: &ZipFile) -> ZipResult<()>
 {
     try!(writer.write_le_u32(spec::CENTRAL_DIRECTORY_HEADER_SIGNATURE));
     try!(writer.write_le_u16(0x14FF));
@@ -66,7 +67,7 @@ pub fn write_central_directory_header<T: Writer>(writer: &mut T, file: &ZipFile)
 
 fn build_extra_field(_file: &ZipFile) -> ZipResult<Vec<u8>>
 {
-    let writer = old_io::MemWriter::new();
+    let writer = Vec::new();
     // Future work
-    Ok(writer.into_inner())
+    Ok(writer)
 }