SCREEN AS 4979886 - Caterpillar

Illustration 1. Cross section comparison of new and former Duo-Cone seals.With the new rings, the measurement used to check the remainder of seal service life is the flange thickness at the outer edge. See Illustration 2. As shown in the illustration, the measurement must be made carefully because of the shoulder, which is only 1.52 mm (.060") from the edge of the flange. Also, before the flange is measured, it must be inspected for a wear lip around the outer edge as shown in Illustration 3. The development of a wear lip at the outer edge is a normal condition any time the edges of the two ring flanges are not exactly even when the seal is installed. A wear lip in this location does not damage the seal ring, and has no effect on seal performance, but it must be carefully ground off before the flange thickness is measured and/or before the seal is installed again. If any type of wear lip is found around the inner edge of the seal face (see Illustration 3), or if the seal face has any scratches or other damage, a new seal must be installed. The seal face must be flat and smooth.
Illustration 2. Measurement of flange thickness on hardened steel rings.
Illustration 3. Location of wear lip on seal ring.Estimates of expected seal life are difficult because of the many differences in machine applications, job conditions, maintenance and other factors which have an effect on seal service life. The chart that follows can be used as a guide to make an estimate of the remainder of seal service life, according to flange thickness.
Adaptable As: Direct replacement. Specific part numbers and applications are not shown here because some groups are not yet available, but each of the new seal groups can be used as a direct replacement for the respective former group. Seal Storage and Hand Contact: Protection from rust and corrosion, expecially on the machined seal face, is very important. The new seals, like existing seals and many other parts, need protection from moisture (water) and/or mechanical damage (scratches, bend stresses, etc.). Damage can also be caused by hand contact because of moisture and salt from the person's body. Be sure seal rings are thoroughly cleaned and have an application of heavy oil before storage. This needs to be done for storage intervals as short as one or two days during service work on the machine.
Installation And Tools
... Use correct tools for seal installation, which are made specifically for this purpose. The same tools are used for the new steel rings which were used for the former cast iron rings.... Be sure the toric ring is not twisted when it is installed on the seal ring.... During installation of used parts, keep the same two seal rings together which have "worn in" together. When two rings have been used together, they must be installed as a "set".... Never mix new and used metal seal rings.... During seal installation, be sure