TUBE AS 3563761 - Caterpillar

A. Find The Leak
1. Pinpoint the leak location. To make sure that the leak is not up higher and draining down, wash down leakage area; watch for the leak to show; place a paper towel above the connection. It will catch any fluid dripping from above.2. Determine if the leak is at a valve spool, rod packing, motor or pump shaft, cracked casting, a piping joint or a hose or tube.B. Sae 37° Flare Connection
1. Causes: Most of the leaks on this connection are due to the lack of tightening or human error. You can't tell if the nut has been tightened by just looking at the connection. If it is more then finger tight, you can't tell from observation how much. 2. Cures: Here is a foolproof method of tightening. Anyone can tell if the joint was tightened and how much:a. Tighten nut finger tight until it bottoms the seats. b. Mark a line lengthwise on the nut and extend it onto the adapter. Use an ink pen or marker. c. Using a wrench, rotate the nut to tighten. Turn the nut the amount The misalignment of the marks will show how much the nut was tightened and, best of all, that it has been tightened.3. What to do if the joint leaks after it has been tightened properly. Disconnect the line and check for:a. Foreign particles in the joint - wash them off.b. Cracked seats - replace them.c. Seat mismatching or not concentric with the threads - replace the adapter.d. Deep nicks in the seats - replace faulty port.e. SAE 45° nuts - When connected to an SAE 37° male flare fitting will leak. The SAE 45° nut is too long and will bottom on adapter hex in sizes 8 and 10 before the seals are tight - use all SAE 37° flare parts. Many of the leakage problems on this type of connection won't show until the unit has had a few hours of service.C. Sae O-Ring Boss Connection
1. Causes: a. Elbows loosen up after short service.b. O-ring leakage after short service.c. O-ring leakage after long service.d. Instant leakage upon start up. Causes may be either human error or faulty parts.2. Cures: Replace o-ring seals and start over. a. Locknut and washer must be to the back side of the smooth portion of the elbow adapter.b. Lubricate the o-ring - very important.c. Thread into port until washer bottoms onto spot face. Is the boss face large enough for the washer? Does hex of the straight adapter fit into spot face?d. Position elbows by backing up the adapter.e. Tighten jam nut.3. Why o-ring lubrication is important: a. Fitting engaged to point where o-ring touches face of boss. Lubrication on o-ring permits it to move in direction "D".b. When o-ring and boss are dry, rotary motion of assembly can cause friction and o-ring can move in direction "C".c. Locknut and washer cannot bottom fully if the o-ring is between the washer and the face of the