Tips on Drive Belt Replacement

Tips on Drive Belt Replacement

Thu Nov 10, 2016 8:00 am

The timing belt, V Belt, Rubber Belt, and Drive Belt are all important parts of an internal combustion engine that synchronizes the rotation of the crankshaft and the camshaft to push the car.


Automotive Rubber Drive Belts usually fail because they are old, brittle, or rotted. They are very durable, however, engine heat is usually not kind to rubber and plastic components in an engine bay. How do you check your drive belts? Well, if you have a multi-ribbed belt such as a serpentine belt, look for missing chunks of rubber. Make sure there are no gaps between the ribs of the belt. For V-belts, look at the side walls of the belt. It should not be shiny or glazed, but if it is, it indicates that the belt is slipping and is probably not under the correct amount of tension.

Another cause of drive belt failure is faulty pulleys. They should spin smoothly and shouldn't wobble at all. The pulley should not have any grease coming out of it. If it does, the ball bearing seal might be broken. Ball bearings work better with proper lubricant. Without it, a catastrophic pulley failure is imminent and it should be replaced sooner rather than later. The pulley should not be able to move from front to back and should not "slide" on its axle.

Idler/tensioner pulleys should provide the right amount of tension on the belt for the system to operate properly. There is normally a tension indicator on the idler and it should be close to midpoint. It should not be on the "loose" part of the indicator. This means that the drive belt has stretched and should be replaced.

As a rule of thumb, the first step to properly change your drive belts is to make sure that you can put the new belt on properly. Usually, there is a sticker with a diagram of the belt routing path through the accessories. Look for this and make sure that you understand the diagram. If you're not lucky enough to have a diagram, get a piece of paper and pen and draw a diagram of your own. Label the accessories with letters such as "A" for alternator and "C" for compressor. This will help identify the accessories and keep the proper orientation.

Next, you need to find your idler/tensioner pulley. Then, what you have to do is apply opposite force to the pulley. You do this by inserting a ratchet or breaker bar into the square hole in the pulley. Sometimes this hole may not be a square as is the case for many German cars. These cars may have a star shaped hole in the center of the pulley, thus requiring the fitting of a torx bit to your ratchet or breaker bar. So, if the pulley is pushing in one direction, you need to pull in the opposite direction.

When you do this, you should feel a gradual, but smooth release of tension on the pulley. Push or pull the idler pulley until it stops. At this point, you will see that the drive belt is quite loose. Hold the breaker bar or ratchet with Rubber V Belt one hand and remove the belt with the other. Once the drive belt is removed off the idler pulley, you can slowly release the opposing tension that you applied to the pulley. Continue to remove the belt from all of the other accessories.


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