1. PULLEY BOLT: Fastens pulley to arm. In some cases can also be used as a lift feature for belt installation.

2. DUST SHIELD: Prevents contaminants from entering pulley ball bearing.

3. BALL BEARING: Maintenance free and sealed for life.

4. PULLEY: Steel or plastic construction, depending on application. Due to belt length considerations, pulley diameters are application specific.

5. FRONT PLATE: Retains the complete tensioner assembly. Due to mechanical staking feature, tensioners are non-serviceable and cannot be disassembled safely.

6. THRUST WASHER: Provides additional damping and alignment.

7. ARM: Robust and precision aluminum diecasting. Transmits torque from spring to pulley to provide constant belt tension. Arm also provides environmental protection for internal components.

8. PIVOT BUSHING: Self-lubricating, highly wear resistant polymer component. Function is to ensure proper tensioner arm alignment relative to belt and counters tilting.

9. SPRING: Critical part of tensioner. Designed to provide constant, trouble-free tension to belt for life of tensioner. Round wire design not affected by corrosion or coil-to-coil contact. Does not require a PTFE filler strip to prevent spring lock-up.

10. SPRING SUPPORT/DAMPING ELEMENT: Provides primary damping for smooth tensioner and accessory drive system operation. Damping varies with spring torque for consistent level of damping throughout operating range. Engineered, highly wear resistant polymer.

11. SPINDLE or BRACKET: Robust and precision aluminum diecasting with integral locating pin. Keeps the arm ‘true’ to belt. Provides a pivot center for arm and anchors spring. Ensures angular alignment or proper placement on engine. Other accessories or passages for engine coolant may be integrated.

12. CAST LOCATING PIN: Incorporated into the diecasting for exact Original Equipment fit and accuracy. The purpose of the pin is to accurately locate the tensioner on the engine and does not have torque transmitted through it, after the mounting bolt is torqued down.

Represents typical construction

COMPONENT

SPECIFICATION

Arm
Spindle or Bracket

SAE 380 or equivalent Diecast Aluminum

Insert Bearing
Spring Support
Thrust Washer

ASTM D4066 PA0920

Spring

ASTM A401 (SAE J157) Chromium Silicon Steel

Pulley

SAE 1008/1010 with 4350MA336 electrodeposited coating
or
ASTM D4000G50 Glass Filled Nylon 6

Dust Shield

SAE 1008/1010 Steel with Zinc/Chromate Finish

Front Plate

SAE 1008/1010 Steel with Zinc/Chromate Finish

Ball Bearing

SAE 52100 or DIN Steel NBR or Polyacrylic Seals

Bolt

Cold Headed Steel

Thread Size/Type

Recommended Torque (ft.lbs)

Typical Head Size Reference

16 – 24
24 – 35
40 – 48
60 – 70

10 or 13 mm
9/16 inch
15 or 17 mm
18 or 19 mm