1942 - 1947 Chevrolet Shop Manual



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	by the pistons to lubricate them, the glucose will form a sticky rim around the cylinders, preventing piston action. The fourth type, or mineral oil such as motor oil in shock absorber fluid, is the one to guard against most strenuously. Even slight traces of mineral oil are enough to destroy the sealing qualities of the rubber cups in two or three days. Cylinders and parts should never be washed in gasoline, as even the small amount of mineral oil present in gasoline will affect the rubber seals. The last named type, or plain alcohols, most of which contain up to 10% water, should never be used as the alcohol has no lubricating properties at all and, due to its extreme thinness, will leak past the rubber cups and saturate the brake linings. In the event that improper fluid has entered the system, it will be necessary to— 1. Drain the entire system. 2. Thoroughly and vigorously flush the system with clean alcohol, 188 proof, or a hydraulic brake system cleaning fluid known to the industry as "Declene." 3. Replace all rubber parts of the system including brake hoses. 4. Refill the system with G. M. Hydraulic Brake Fluid, Super No. 9. HYDRAULIC BRAKE TUBING The hydraulic brake tubing is a double layer flexible steel, copper-coated, tin-plated tubing which resists corrosion and also stands up under the high pressures which are developed when applying the brakes.	The important thing in connection with making up hydraulic brake pipes is the proper flaring of the ends of the tubing for the compression couplings. Unless the tubing is properly flared the couplings will leak and the brake will become ineffective. This safety steel tubing must be double-lap flared at the ends in order to produce a strong, leak-proof joint. The brake tube flaring tool shown in Fig. 6 is used to form the double-lap flare.

		Fig. 7— Single and Double Lap Flare on Tubing End Fig. 7 shows two pieces of tubing—one with a single-lap flare ("A") and the other with the double-flap flare ("B"). It will be noted that the single-flap flare split the tubing while the one shown in "B" has a heavy, well-formed joint. DIRECTIONS 1. Cut the tubing to the desired length, using a tube cutter to prevent flattening the tubing. Square off the end with a fine-cut mill file, then ream the sharp edges with the reamer blade provided on the tube cutter, Fig. 8.


		Fig. 8-Cutting Hydraulic Brake Tubing 2. Place new compression coupling nuts on the tubing. Dip end of tubing to be flared in hy-
	Fig. 6-Hydraulic Brake Tubing Flaring Tool