PULLEY-CRANKSHAFT 7W5691 - Caterpillar

Illustration 29 g03150656
Results of incorrect assembly
If a Duo-Cone seal is installed incorrectly, there is a risk of misalignments, twists, and bulges to the rubber toric that will cause early hour failures. Refer to Illustration 29.Final Assembly of Duo-Cone Seal Group
Using a lint-free wipe clean the seal ring faces with approved cleaner.Using a lint-free wipe, pre-lubricate one seal ring face with the fluid being sealed or approved oil. When pre-lubricating, do not allow the fluid to contact the rubber toric to avoid slippage of the toric.In the case where the fluid being sealed is not available, refer to 1E4485 for a list of approved Duo-Cone seal assembly lubricants.Some instances may require the use of a Molykote GN-paste (CAT P/N: 6V-4876) as the assembly lubricant in place of an approved oil. Contact the Caterpillar Dealer Solutions Network for any questions concerning seal defects.Refer to Table for the Caterpillar part numbers associated with the Molykote Paste.
Table 4
Supplier ProductName CAT Part Number Product Size
Dow Corning Molykote 6V-4875 0.5 kg (1 lb) Can
Dow Corning Molykote 6V-4876 5 kg (11 lb) Can
Illustration 30 g03150696
Concentric alignment of two housings
Align the two housings so the housings are concentric and slowly bring the two seal ring faces together. Refer to Illustration 30.Do not let the housings rock excessively as this risks damage to the seal rings. Damages may include seal misalignment or breaking of the seal rings.Do not let the seal ring faces bang together, as this motion risks breaking the seal ring.Results of Incorrect Assembly of the Duo-Cone Seal Group
If the rubber toric slips at one location, but not all the way around the rubber toric, the toric can twist. This twist can cause the seal ring to cock or misalign.
Illustration 31 g03150697
Cocked Duo-Cone seals
Severely cocked seals can cause uneven pressure on the seal. This results in an excessive wobbling motion. Refer to Illustration 31.Wobble may be defined as a seal that has movement exceeding 1.0 mm (0.04 inch) in the axial direction. Minor wobble of seals may exist and is normal in the assembly. For additional information regarding cocked seals/wobble contact the Caterpillar Dealer Solutions Network (DSN).Wobble can cause dirt to enter by pumping mud and contamination past the rubber toric. The wobble lead to oil pumping between the rubber toric and housing (retainer), and toric and seal ring interface which can cause the seal to spin.Uneven pressure on the seal faces as a result of an excessively cocked seal, can cause galling, scoring, and leakage of the seal assembly.FAILURE MODES DISCUSSION
While metal face seals generally perform satisfactorily, premature failure can occur for a number of reasons, but can be avoided or minimized through proper seal design and/or installation.Failures of Duo-Cone Seals (oil out or dirt in) can occur in-house or in the field. The different modes of failure that the seals can experience are listed below:
Oil Leakage
Galling
Pumping of Mud Past the Toric and Into the Oil Compartment
Toric Failure
Seal Ring Breakage
Illustration 32 g03150698The failure modes can be either immediate (in-house) or long term