Corteco is urging technicians to fit its TVD pulley kits with the supplied bolts or risk damage.
Pulleys should be checked every 90,000 km and replaced together with the bolts and belt.
A Corteco spokesperson said: “Corteco recommends replacing the bolts with the pulley.
“In serial production torque-to-yield (TTY) bolts are often used which are tightened by automatic bolt tightening devices to just above their elasticity range.
“The bolt undergoes lasting deformation and/or stretching.
“Re-using such bolts poses considerable safety risks and is not recommended.
“As a result of the deformation, the usual ratio between torque and preload cannot be achieved.
“Result – the screw can become loose or even break.”
Corteco’s TVD pulley kits include the pulley, washer, bolts, mounting information and tools.
The spokesperson added: “We know replacement bolts are difficult to identify, but Corteco offers you the widest selection in OE quality.
“Purposely designed original pulleys and bolts guarantee straightforward assembly and the highest degree of safety.”