The next time you work with a drive belt, timing belt, or timing chain, you’ll likely have to loosen a tensioner pulley to eliminate it. Subsequent these general recommendations and specific instructions from your owners manual or restoration manual, your belt or chain will function for the life span of your car.

Toyota and various other timing belt tensioners are loosened simply by removing them from the engine. You must slowly compress them in a bench vice and lock them with a pull-pin before reinstallation.
Hydraulic (not hydraulic-damped) tensioners are almost always positioned in the timing case, mostly upon vehicles with timing chains, though some are used in combination with timing belts. Hydraulic tensioners are powered by oil pressure from the engine essential oil pump and may press on a tensioner pulley (timing belts) or stress slipper (timing chain). You’ll likely need the year, make, and model information, and you may have to use special equipment for this sort of tensioner pulley.
Typically, a hydraulic tensioner must be “reset” and locked after removing it from the engine. Take away the lock only Car Pulley Belt following the tensioner, pulley, or slipper, and timing belt or timing chain are set up and aligned.

The spring maintains tension, as the hydraulic damper keeps it from bouncing under load changes. This prevents timing belts and timing chains slapping and jumping teeth and retains drive belts from slipping and producing noise. To loosen a drive belt springtime tensioner pulley, refer first to the repair manual or owners manual’s specific year, make, and model information.
You might need a special tool, but many spring tensioners have a square hole, for a 3/8” or 1/2” breaker bar, or a hex or square protrusion for a wrench or socket. Using the correct tool, release stress on the belt. You will have to hold some springtime tensioners while slipping on a fresh belt. Others may have a locking mechanism, such as a hole for a locking pin or hex key.

To loosen an NAI tensioner, loosen the locking nut or bolt, after that cool off the tensioner screw. Force the pulley toward the various other pulleys or accessories, loosening the belt.
Spring tensioner pulleys, as the name implies, use a spring to hold tension upon the belt. Most, if not absolutely all, springtime tensioner pulleys are NAI tensioners and include a hydraulic damper. They are more complex and expensive but don’t require modifications and are less susceptible to user error.