Service and Repair Manual

each point where bubbles appear with a wire clip. If there is a leak in the tube, remove it as described in this action, paragraph 2.i.(1), and insert a new one by soldering it ln place as described ln this section, paragraph 2.i.(2). If the leak appears around the jacket, or the core face, the leak can usually be soldered without disturbing any of the assembled parts.

The same test should be made after any repairs are completed.

     (2) Coolant Radiators. - The leak test for the coolant radiators should be conducted in the same manner as for the oil cooler except that an air pressure of not more than 10 pounds per square inch is to be applied.

     h. Repair Eguipment Reguired. - The following equipment is required for the complete repair work of oil coolers and coolant radiators in accordance with this prospectus:

     (1) Oxyacetylene torch, oxygen-acetylene tanks, and pressure regulator with several sizes of torch tips.

     (2) Small gas-fired furnace for heating copper soldering irons.

     (3) At least two large gas -heated soldering irons.

     (4) At least four special tube pulling irons. (See figure below.)

     (5) Silver solder wire approximately 1/16 inch in diameter; soft tin lead solder wire approximately 1/8 inch in diameter.

     (6) Zinc chloride flux for the soft solder and also flux for the silver solder.

     SQUARE OFF END OF PLAIN SOLDERING IRON (AT LEAST A 3-POUND IRON). DRILL 3/ 8-INCH HOLE IN SQUARED END 1-1/4 INCHES DEEP. INSERT COPPER POINT AND SILVER SOLDER TO IRON. BE SURE TO SWEAT SOLDER FULL LENGTH OF HOLE.

     i. Repairs.

     (1) Removing Single Tubes. - Collapsed tubes usually will not leak but should be removed because of their effect on the heat dissipation. Instruction for repair and replacement of collapsed tubes also applies to the repair and replacement of a leaking tube. The procedure is as follows: Heat the special tube pulling irons in the gas furnace. While the irons are heating, clean the original soldered ends of the tubes to be pulled, with concentrated hydrochloric acid and swab with zinc chloride flux. The cleaning and fluxing should be done with a small hair brush or swab. With the irons hot, insert the tip of one iron into one end of the tube and the tip at the other iron into the opposite end of the tube, making sure they are in the same tube.

Corresponding tube ends can be identified easily by pushing a wire through the tube and as the wire is withdrawn from the tube, insert one iron in the end from which the wire has been withdrawn and then as the wire is withdrawn from the other end, insert the other iron in that end. Then applying a pushing pressure directed toward the core face with one iron, hold the other iron against the tube with just enough pressure to keep it in place and apply a slight oscillating motion of 10 or 15 degrees to both irons. If the irons are hot enough the solder bond between the tube to be removed and the adjacent tubes will loosen almost immediately and the hex tube ends will assume a round shape and will break loose from their position in the core. Then the irons may be removed from both ends of the tube. Using a pair of pliers, pull the protruding end of the tube out through the core.

     (2) Replacing New Tubes. - To replace the new tube, first flux each end of the new tube and tin it with a lead tin solder on the hex ends only. Then take the special tube pulling iron and round up the opening in the core where the old tube was removed so that the new tube may be easily inserted in case there are any lumps of solder adhering to the opening. Next flux the openings in the core where the old tube has been removed and insert the new tube. Use a pair of sharp-nosed pliers and re-form the hexagons of the tubes adjacent to the new tubes. After refluxing use the standard soldering iron and solder over the face of the core with a back-and-forth motion of the iron:

     (3) Removing Large Sections of Core. -The above procedure applies to removing one tube or several tubes. However, if a large section of the core must be removed, it is safe to use an oxyacetylene flame bn both ends of the core to melt out large sections at one time.

     (4) Repair of Core Surface Leaks. - Core surface leaks may be repaired by fluxing the surface of the core at the point of leakage with a zinc chloride flux, and then using a hot iron apply a back-and-forth motion, and solder over the point of leak.

     (5) Repair of Surface Leaks Between the Core and Shell Assembly. - Flux at the point of leak with zinc chloride flux and either apply an iron directly to the solder bond, and re-solder at the point of leak, or use a flame on the outside surface of the shell to apply heat to the brass and using the solder wire feed the solder between the periphery of the core and the inside of the shell.

     (6) Leaks Through Silver solder Bond of the Shell Assembly. - These leaks may be repaired by the application of soft solder, using either a flame or an iron after first fluxing the point of leak.

     (7) Dents in Shell. - Large dents in the shell may be corrected by applying an air pressure of 30 to 40