GASKET-COVER 2A3691 - Caterpillar

The upper seal is between the bearing and the gear compartment. There is normally grease on both sides of the upper seal. A new upper seal can not be installed unless the upper frame and carbody are separated. If the upper seal is damaged or leaking, it is not normally practical to install a new seal until the machine is disassembled for other reasons. Add lubricant as needed when the machine is operated with a damaged or leaking upper seal.
The lower seal is between the bearing and the lower side of the machine. The lower seal keeps dirt from the bearing. A damaged or leaking lower seal must be removed and a new lower seal installed as soon as possible to prevent damage to the bearing. A machine can be operated with a damaged or leaking lower seal if the lubrication interval is shortened so the bearing always has lubricant and the dirt is flushed out by excess (more than is needed) grease. But, the machine cannot be operated in conditions where water or mud can get into the bearing. A machine must not be operated for a long period of time with a damaged or leaking lower seal.
On 235 and 245 Excavators, machine disassembly is not necessary to install a new lower seal. On the 225 Excavators, the upper frame and carbody must be separated to install a new lower seal.
Procedure to Install Seal
1. The temperature must be 60°F (15°C) or higher. Remove all of the old seal.2. Clean all grease and foreign material from the seal groove. The seal groove must be completely clean. If there is any rust in the groove, clean the groove with a wire brush.3. Wash the groove with a solvent. Let the groove become dry.4. An adhesive is needed to hold the seal in the groove. Use 5P3429 Adhesive if possible. If the 5P3429 Adhesive is not available, 5H2471 Cement, Scotch Grip 1300 made by the 3M Company or an equivalent adhesive can be used.5. Start approximately 1 foot (.3 m) from one end of the seal and put the adhesive in the groove and on the part of the seal that goes into the groove. See the instructions on the container for the adhesive. The adhesive must be put on evenly. Do not use too much adhesive since that makes it harder to install the seal and takes more time for the adhesive to dry. It is normally easier to work on the seal in lengths of 3-4 feet (.9-1.2 m).6. Push the seal into the groove with a blunt (not sharp) edge tool. Do not get any oil or dirt on the seal. Do not cut or stretch (make longer) the seal. Do not put the adhesive on approximately 1 foot (.3 m) of each end of the seal or in the groove where the ends of the seal are to be installed.7. Push the ends of the seal into the groove. The ends of the seal must be