diff --git a/modules/benchmarks/src/old/compiler/compiler_benchmark.ts b/modules/benchmarks/src/old/compiler/compiler_benchmark.ts
index 5376c2eb15..b28b000bc3 100644
--- a/modules/benchmarks/src/old/compiler/compiler_benchmark.ts
+++ b/modules/benchmarks/src/old/compiler/compiler_benchmark.ts
@@ -64,8 +64,8 @@ function measureWrapper(func, desc) {
 
 
 class MultiplyDirectiveResolver extends DirectiveResolver {
-  _multiplyBy: number;
-  _cache = new Map<Type, ViewMetadata>();
+  private _multiplyBy: number;
+  private _cache = new Map<Type, ViewMetadata>();
 
   constructor(multiple: number, components: Type[]) {
     super();
@@ -73,7 +73,7 @@ class MultiplyDirectiveResolver extends DirectiveResolver {
     components.forEach(c => this._fillCache(c));
   }
 
-  _fillCache(component: Type) {
+  private _fillCache(component: Type) {
     var view = super.resolve(component);
     var multipliedTemplates = new Array(this._multiplyBy);
     for (var i = 0; i < this._multiplyBy; ++i) {
diff --git a/modules/benchmarks/src/old/naive_infinite_scroll/app.ts b/modules/benchmarks/src/old/naive_infinite_scroll/app.ts
index e9bd7c433d..57434f9948 100644
--- a/modules/benchmarks/src/old/naive_infinite_scroll/app.ts
+++ b/modules/benchmarks/src/old/naive_infinite_scroll/app.ts
@@ -74,7 +74,7 @@ export class App {
   }
 
   // Puts a marker indicating that the test is finished.
-  _scheduleFinishedMarker() {
+  private _scheduleFinishedMarker() {
     var existingMarker = this._locateFinishedMarker();
     if (isPresent(existingMarker)) {
       // Nothing to do, the marker is already there
@@ -88,7 +88,7 @@ export class App {
     }, 0);
   }
 
-  _locateFinishedMarker() { return DOM.querySelector(document.body, '#done'); }
+  private _locateFinishedMarker() { return DOM.querySelector(document.body, '#done'); }
 
-  _getScrollDiv() { return DOM.query('body /deep/ #scrollDiv'); }
+  private _getScrollDiv() { return DOM.query('body /deep/ #scrollDiv'); }
 }
diff --git a/modules/benchmarks/src/old/naive_infinite_scroll/cells.ts b/modules/benchmarks/src/old/naive_infinite_scroll/cells.ts
index 4997e0a9d5..dd34774a67 100644
--- a/modules/benchmarks/src/old/naive_infinite_scroll/cells.ts
+++ b/modules/benchmarks/src/old/naive_infinite_scroll/cells.ts
@@ -71,7 +71,7 @@ export class Stage {
       </div>`
 })
 export class StageButtonsComponent extends HasStyle {
-  _offering: Offering;
+  private _offering: Offering;
   stages: Stage[];
 
   get offering(): Offering { return this._offering; }
@@ -86,7 +86,7 @@ export class StageButtonsComponent extends HasStyle {
     this._computeStageButtons();
   }
 
-  _computeStageButtons() {
+  private _computeStageButtons() {
     var disabled = true;
     this.stages = STATUS_LIST
                       .map((status) => {
diff --git a/modules/benchmarks/src/old/naive_infinite_scroll/common.ts b/modules/benchmarks/src/old/naive_infinite_scroll/common.ts
index 71aa3403c8..3d3aa912c6 100644
--- a/modules/benchmarks/src/old/naive_infinite_scroll/common.ts
+++ b/modules/benchmarks/src/old/naive_infinite_scroll/common.ts
@@ -60,7 +60,7 @@ export class CustomDate {
 }
 
 export class RawEntity {
-  _data: Map<any, any>;
+  private _data: Map<any, any>;
 
   constructor() { this._data = new Map(); }
 
@@ -101,7 +101,7 @@ export class RawEntity {
     return target.remove(last);
   }
 
-  _resolve(pieces, start) {
+  private _resolve(pieces, start) {
     var cur = start;
     for (var i = 0; i < pieces.length; i++) {
       cur = cur[pieces[i]];
diff --git a/modules/benchmarks/src/old/naive_infinite_scroll/scroll_area.ts b/modules/benchmarks/src/old/naive_infinite_scroll/scroll_area.ts
index 3c8a99a159..f07cfb16d0 100644
--- a/modules/benchmarks/src/old/naive_infinite_scroll/scroll_area.ts
+++ b/modules/benchmarks/src/old/naive_infinite_scroll/scroll_area.ts
@@ -33,7 +33,7 @@ import {ScrollItemComponent} from './scroll_item';
     </div>`
 })
 export class ScrollAreaComponent {
-  _fullList: Offering[];
+  private _fullList: Offering[];
   visibleItems: Offering[];
 
   viewPortHeight: number;
diff --git a/modules/playground/src/animate/app/animate-app.ts b/modules/playground/src/animate/app/animate-app.ts
index b3a337b368..b296aed438 100644
--- a/modules/playground/src/animate/app/animate-app.ts
+++ b/modules/playground/src/animate/app/animate-app.ts
@@ -64,7 +64,7 @@ import {Component, animate, keyframes, state, style, transition, trigger} from '
 })
 export class AnimateApp {
   public items: any[] /** TODO #9100 */ = [];
-  public _state: any /** TODO #9100 */;
+  private _state: any /** TODO #9100 */;
 
   public bgStatus = 'focus';
 
diff --git a/modules/playground/src/model_driven_forms/index.ts b/modules/playground/src/model_driven_forms/index.ts
index d71abcc806..4135041f12 100644
--- a/modules/playground/src/model_driven_forms/index.ts
+++ b/modules/playground/src/model_driven_forms/index.ts
@@ -67,7 +67,7 @@ class ShowError {
     return null;
   }
 
-  _errorMessage(code: string): string {
+  private _errorMessage(code: string): string {
     var config = {'required': 'is required', 'invalidCreditCard': 'is invalid credit card number'};
     return (config as any /** TODO #9100 */)[code];
   }
diff --git a/modules/playground/src/template_driven_forms/index.ts b/modules/playground/src/template_driven_forms/index.ts
index e736e7f9fb..359b0959f7 100644
--- a/modules/playground/src/template_driven_forms/index.ts
+++ b/modules/playground/src/template_driven_forms/index.ts
@@ -93,7 +93,7 @@ class ShowError {
     return null;
   }
 
-  _errorMessage(code: string): string {
+  private _errorMessage(code: string): string {
     var config = {'required': 'is required', 'invalidCreditCard': 'is invalid credit card number'};
     return (config as any /** TODO #9100 */)[code];
   }
diff --git a/modules/playground/src/todo/app/TodoStore.ts b/modules/playground/src/todo/app/TodoStore.ts
index 7190e8d35c..f9a79ad796 100644
--- a/modules/playground/src/todo/app/TodoStore.ts
+++ b/modules/playground/src/todo/app/TodoStore.ts
@@ -20,7 +20,7 @@ export class Todo extends KeyModel {
 
 @Injectable()
 export class TodoFactory {
-  _uid: number = 0;
+  private _uid: number = 0;
 
   nextUid(): number { return ++this._uid; }
 
diff --git a/modules/playground/src/web_workers/todo/services/TodoStore.ts b/modules/playground/src/web_workers/todo/services/TodoStore.ts
index 14b809b2d8..6b33f611b9 100644
--- a/modules/playground/src/web_workers/todo/services/TodoStore.ts
+++ b/modules/playground/src/web_workers/todo/services/TodoStore.ts
@@ -24,7 +24,7 @@ export class Todo extends KeyModel {
 
 @Injectable()
 export class TodoFactory {
-  _uid: number = 0;
+  private _uid: number = 0;
 
   nextUid(): number { return ++this._uid; }