It is very important that bolts and nuts are tightened properly–this is called torquing

Torque Specifications Tightening values given by the auto manufacturer Normally given for all precision assemblies, such as engines, transmissions, and differentials Factory specifications should be used –general bolt torque chart may be used if factory specs are not available

Bolt Torque Chart

Bolt Tightening Sequence Used to make sure that parts are fastened evenly Creates an even, gradual clamping force along the entire mating surface of the parts Crisscross pattern is often recommended

Bolt Tightening Sequence Service manual pattern for a cylinder head

Bolt Tightening Sequence Service manual pattern for wheel lug nuts

Torque Wrench Rules Keep a steady pull on the wrench Clean fastener threads Avoid using swivel joints When reading a torque wrench, look straight down at the scale Use manufacturer’s specifications when available

Torque Wrench Rules When manufacturer’s specs are not available, use general specs in a crisscross pattern To avoid a false reading, pull only on the handle Tighten bolts and nuts in four steps Retorque when required –some assemblies must be retightened after operation and heating

Torque Wrenches