How to Install a Belt on a Pulley?
2 Answers
Shorten the center distance to allow the belt to be properly installed; do not pry the belt into the pulley groove. Using tools to stretch the belt over the pulley groove can easily damage both the belt and the pulley groove. If a tensioner pulley is required on the transmission device, it must be installed with a grooved pulley supporting the inner side of the transmission belt, preferably on the slack side of the belt. The tensioner pulley should be positioned close to the large pulley. The movement range is determined after the transmission device is properly installed. During installation, the belt should at least fit over the outer diameter of one of the pulleys, and some elongation of the belt is permissible.
Last time I helped my neighbor replace the alternator belt, it was quite a hassle. Sharing some tips: First, study the belt routing diagram in the engine bay (usually on a sticker under the hood), or take a photo of the old belt's path with your phone. Prepare a suitable new belt, then use a wrench to turn the tensioner pulley counterclockwise (different cars have different mechanisms - some require loosening a bolt) until the belt is slack enough to remove the old one by hand. When installing the new belt, ensure it's properly seated in all pulley grooves - start with the large crankshaft pulley and finish with the tensioner pulley. The most critical part is adjusting the tension - press the belt midway with your finger; 5-6mm deflection is ideal. Too tight and you'll damage bearings, too loose and it'll squeal/slip. After installation, manually rotate the belt two full turns to check alignment, then run the engine for 10 minutes to confirm no abnormal noises. Remember to wear gloves throughout to prevent cuts!
