TIMING BELT - FAULT FINDING

   
BELT BACKING CRACKS  
 
FEATURES:    
 Severe cracking on belt back.
CAUSES:     
Extreme temperatures (hot and cold).
GENERAL:  
Cracks of this type will weaken the back of the belt producing hundreds of fatigue points which will lead to ultimate belt break. The cause of extreme temperatures can be on opposite scales.
TOO COLD. During very bad weather conditions where temperatures fall below 0°C the belt can become rigid and less pliable. Rotating a frozen belt will initiate belt cracks.
TOO HOT. Normally associated with friction due to seized/or seizing idler pulleys. Heat obviously work hardens the rubber backing inducing a brittle skin.
ACTION:  
In all instances, be it hot or cold failures, it pays to play safe and renew belt idler pulleys.
   

 
OIL CONTAMINATION  
 
FEATURES:    
Belt visually oily/greasy.
CAUSES:     
Oil leaks.
GENERAL:  
Oil seal leakage will centrifuge oil onto the belt. Dust and particle contamination will form a sticky residue. Rubber may become swollen and the teeth fabric will lose its adhesion and begin to delaminate. Belt's tensile properties will be lost and failure will result.
ACTION:  
Cure any oil leaks and check at regular intervals.