The next time you utilize a drive belt, Car Pulley Belt timing belt, or timing chain, you’ll likely need to loosen a tensioner pulley to remove it. Subsequent these general suggestions and specific instructions from your owners manual or restoration manual, your belt or chain will function for the life of your car.
Toyota and other timing belt tensioners are loosened simply by removing them from the engine. You need to 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 on automobiles with timing chains, while some are used with timing belts. Hydraulic tensioners are run by oil pressure from the engine oil pump and could press on a tensioner pulley (timing belts) or stress slipper (timing chain). You will likely need the entire year, make, and model information, and you may need to use special tools for this sort of tensioner pulley.
Typically, a hydraulic tensioner needs to be “reset” and locked after removing it from the engine. Remove 
the lock only following the tensioner, pulley, or slipper, and timing belt or timing chain are installed and aligned.
The spring maintains tension, while the hydraulic damper keeps it from bouncing under load changes. This prevents timing belts and timing chains slapping and jumping tooth and retains drive belts from slipping and making sound. To loosen a drive belt springtime tensioner pulley, refer initial to the restoration manual or owners manual’s specific 12 months, make, and model details.
You may 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 tension on the belt. You’ll need to hold some springtime tensioners while slipping on a new belt. Others may possess a locking mechanism, such as a hole for a locking pin or hex important.
To loosen an NAI tensioner, loosen the locking nut or bolt, then back off the tensioner screw. Press the pulley toward the other pulleys or add-ons, loosening the belt.
Spring tensioner pulleys, because the name implies, use a springtime to hold tension upon the belt. Most, if not all, springtime tensioner pulleys are NAI tensioners and include a hydraulic damper. They are more complex and costly but don’t require changes and are less prone to user error.