diff --git a/core/modules/filter/filter.module b/core/modules/filter/filter.module
index 0747250..b4e09a5 100644
--- a/core/modules/filter/filter.module
+++ b/core/modules/filter/filter.module
@@ -215,9 +215,11 @@ function filter_format_save($format) {
   }
   $filter_info = filter_get_filters();
   foreach ($filter_info as $name => $filter) {
-    // Add new filters without weight to the bottom.
+    // If the format does not specify an explicit weight for a filter, assign
+    // a default weight, either defined in hook_filter_info(), or the default of
+    // 0 by filter_get_filters().
     if (!isset($format->filters[$name]['weight'])) {
-      $format->filters[$name]['weight'] = 10;
+      $format->filters[$name]['weight'] = $filter['weight'];
     }
     $format->filters[$name]['status'] = isset($format->filters[$name]['status']) ? $format->filters[$name]['status'] : 0;
     $format->filters[$name]['module'] = $filter['module'];
diff --git a/core/modules/filter/filter.test b/core/modules/filter/filter.test
index f6476f5..06a161a 100644
--- a/core/modules/filter/filter.test
+++ b/core/modules/filter/filter.test
@@ -1823,3 +1823,62 @@ class FilterHooksTestCase extends DrupalWebTestCase {
   }
 }
 
+/**
+ * Tests filter settings.
+ */
+class FilterSettingsTestCase extends DrupalWebTestCase {
+  protected $profile = 'testing';
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Filter settings',
+      'description' => 'Tests filter settings.',
+      'group' => 'Filter',
+    );
+  }
+
+  /**
+   * Tests explicit and implicit default settings for filters.
+   */
+  function testFilterDefaults() {
+    $filter_info = filter_filter_info();
+    $filters = array_fill_keys(array_keys($filter_info), array());
+
+    // Create text format using filter default settings.
+    $filter_defaults_format = (object) array(
+      'format' => 'filter_defaults',
+      'name' => 'Filter defaults',
+      'filters' => $filters,
+    );
+    filter_format_save($filter_defaults_format);
+
+    // Verify that default weights defined in hook_filter_info() were applied.
+    $saved_settings = array();
+    foreach ($filter_defaults_format->filters as $name => $settings) {
+      $expected_weight = (isset($filter_info[$name]['weight']) ? $filter_info[$name]['weight'] : 0);
+      $this->assertEqual($settings['weight'], $expected_weight, format_string('@name filter weight %saved equals %default', array(
+        '@name' => $name,
+        '%saved' => $settings['weight'],
+        '%default' => $expected_weight,
+      )));
+      $saved_settings[$name]['weight'] = $expected_weight;
+    }
+
+    // Re-save the text format.
+    filter_format_save($filter_defaults_format);
+    // Reload it from scratch.
+    filter_formats_reset();
+    $filter_defaults_format = filter_format_load($filter_defaults_format->format);
+    $filter_defaults_format->filters = filter_list_format($filter_defaults_format->format);
+
+    // Verify that saved filter settings have not been changed.
+    foreach ($filter_defaults_format->filters as $name => $settings) {
+      $this->assertEqual($settings->weight, $saved_settings[$name]['weight'], format_string('@name filter weight %saved equals %previous', array(
+        '@name' => $name,
+        '%saved' => $settings->weight,
+        '%previous' => $saved_settings[$name]['weight'],
+      )));
+    }
+  }
+}
+