HEAD GP-CYL -UTN 0R3719 - Caterpillar

things affect the torque/tension relationship of fasteners. But, the greatest factor on this relationship is the condition of the sliding surfaces of the fastener (bolt or nut).
Caterpillar has recently introduced phosphate/oil-coated bolts (the latest black bolts). These bolts provide better control and predictability of the resulting clamp load based on a given torque. Oil in the phosphate coating is the key to this improvement. Over a period of time, oil can be lost to the fastener environment. To compensate for this loss, Caterpillar recommends the following reuse procedure for phosphate/oil-coated bolts.
Unless otherwise directed, clean the bolt with Hydrosolv 4106 Cleaner or an equivalent nonacid cleaner and LUBRICATE the sliding surfaces of the bolt with engine oil or an available lubricating oil.
Hydrosolv 4106 Cleaner is available in three sizes: 1U8811-1 gal., 1U5509-5 gal., and 1U5510-55 gal.This procedure is also recommended for the new zinc-plated bolts. The zinc-plated (with dichromate) bolts have a yellow/bronze appearance and provide superior corrosion resistance compared to the phosphate/oil-coated bolts.
If the Service Manual specifies the use of 9S3263 Thread Lock or other similar substances, DO NOT reoil the bolt prior to reuse. Instead, remove any previously-applied thread lock that may still exist on the bolt. Then apply a new coating of 9S3263 Thread Lock. The lubricating properties of the thread lock will be sufficient to insure the correct torque/tension relationship.
Do not use anti-seize compound in high-torque applications unless it is specified in the Service Manual, or you may get the bolt too tight.