Usage:
3176 (2YG, 7LG),
3176B (9CK),
C-10 (2PN),
C-12 (1YN) Truck Engines
Reference: See "New Strap Used In Alternator Mounting Groups" and "New Belt Tighteners Used In Alternator Mounting Groups" in this issue.
Description of Change: A new film (decal) is used in the belt tightener group. The new decal indicates when the belts have stretched beyond the automatic spring tightener's capability to correct.
The new decal is located on the side of the belt tightener and is visible any time the hood is open. The decal has an upper and lower red zone and a central green zone. When the belt tightener is in the green zone, the system is in the correct operating range. If the belt tightener is in the green zone, belt stretch is not excessive. If the belt tightener is in the upper red zone, the belt has stretched and the belt must be replaced or an adjustment must be made to the system. If the belt tightener is in the lower red zone the belt is to short and should be replaced.
NOTE: The belt tension should only be checked when the engine is stopped. Caterpillar recommends checking the belt tension at each oil change.
Adaptable To: The 132-1123 Film is adaptable to 3176 (2YG and 7LG) and 3176B (9CK) Truck Engines. The 134-1018 is adaptable to C-10 (2PN) and C-12 (1YN) Truck Engines.
Installation
Illustration 1, Side view of belt tightener showing placement of 132-1123 Decal (A) on spring case (D) between parting line and pivot arm. Heavy black line (B) of decal. Shoulder of pivot arm used as pointer indicator (1). Initial red zone (2). Green operating range (3). Red zone (4). Beginning of overtravel zone (C).
Illustration 2, Side view of belt tightener showing movement of pointer indicator after tightening the belt. Heavy black line on decal (B) has moved in relationship to shoulder of pivot arm used as pointer indicator (1). Pointer indicator (1) is now in the green operating range (3).
Remove the belt and allow the tightener to come to rest on the free arm stop (6).
NOTE: Removing the tightener is not necessary but may be easier.
Prepare the spring housing surface to accept the decal by removing all loose paint, grease, oil and dirt. Remove the masking on the face of the decal and the backing. Apply the decal to the case of the tightener by aligning the heavy black line on the decal (B) to the shoulder of the tightener arm on the right hand (outboard) side of the tightener.
NOTE: When checking the decal for the correct position, always have the engine OFF.
Illustration 3, typical view of alternator group, spring tang (5), free arm stop (6).
When changing to a new belt, swing the alternator (inboard) to the initial part of the slot. Run the engine for five minutes to allow for initial belt stretch and seating in the grooves. Adjust the indicator to the far edge of the green zone (overtravel area) (C). Make sure that the back of the belt does not hit the spring tang (5).
When making an adjustment, always adjust as close to the overtravel zone (C) as possible without rubbing the belt on the spring tang (5). This will allow for the most time between adjustments.