The next time you work with a drive belt, timing belt, or timing chain, you’ll likely have to loosen a tensioner pulley to remove it. Subsequent these general suggestions and specific instructions from your own owners manual or Car Pulley Belt restoration manual, your belt or chain will function for the life span 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 nearly always positioned in the timing case, mostly upon automobiles with timing chains, though some are used in combination 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 pressure slipper (timing chain). You will likely need the entire year, make, and model details, and you may need to use special equipment for this kind 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 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 tooth and maintains drive belts from slipping and making sound. To loosen a drive belt spring tensioner pulley, refer initial to the restoration manual or owners manual’s specific calendar year, make, and model details.
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 appropriate tool, release pressure on the belt. You’ll need 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, then back off the tensioner screw. Force the pulley toward the various other pulleys or accessories, loosening the belt.
Spring tensioner pulleys, because the name implies, use a springtime 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 changes and are less susceptible to user error.