HUB 2125839 - Caterpillar

Cylinder Liners
A) Water Spots
Many cylinder liners are thrown away because of water spots on cylinder liner walls. Water spots and/or light rust on the cylinder liner walls can be caused when water has been in a cylinder for several days or weeks or when the correct procedure for storage of the parts is not followed.
Rust is never permitted on the inside of a liner, but certain water spots are permitted after a reconditioning operation with a FLEX-HONE. Water spots can be different sizes and shapes. Most of the time, the water spots are larger than the spots shown in Illustration 1. If a cylinder liner has water spots that can not be felt with the fingernail or measured with a dial bore gauge, the liner can be used again if no other defects are present. These types of spots are normally surface discoloration only.
Illustration 1. USE AGAIN--Cylinder liner with water spots that can not be felt or measured.Put cylinder liners that have water spots and/or light rust through a reconditioning operation. Use a FLEX-HONE to clean the inside of the liner and give the proper surface finish. After the FLEX-HONE has been used, see if the water spots are really small pits. The liner must not have scratches, small pits or rust on the inside walls that can be felt with a fingernail or fingertip.
B) External Pits
If the outside of a liner has pits that go into the lower two seal grooves at the bottom of the liner or into the filler band groove at the top of the liner, do not use it again.
If the liner has pits on the outside between the seal grooves and filler band groove and they are more than .090" (2.3 mm) deep, do not use the liner. Grind an 8S2251 Drill as shown in Illustration 2 to make a gauge to check the depth of the pits when a visual inspection of the pit is not clear. Always install liners with pits so the pits are toward the front or rear of the engine.
Illustration 2. Modification to 8S2251 Drill.C) Additions to FLEX-HONE Procedure
Check the condition of the FLEX-HONE at regular intervals. The tips are worn or dirty if liners are still shiny with the normal number of strokes of the FLEX-HONE. If the FLEX-HONE is worn, use a new FLEX-HONE or have the manufacturer install new tips. After the FLEX-HONE procedure is completed, clean the inside of the liner with a nylon brush and a strong detergent and water solution. No other method is approved. Clean the FLEX-HONE with soap and water or solvent.
1) During the FLEX-HONE procedure, a good solvent can be used on the FLEX-HONE instead of 10, 20 or 30 weight oil. Never use the FLEX-HONE when it is dry.2) Because drills have different speeds, it can be necessary to change the rate given in the FLEX-HONE Procedure (Form SEBF8001-01). Use a cylinder liner without wear as a reference to get the correct angle of the "Crosshatch" pattern