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    GM Chevy Mid-Size Cars 1964-1988 Repair Guide

    Brake Hoses and Pipes

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    HYDRAULIC BRAKE LINE CHECK



    The hydraulic brake lines and brake linings are to be inspected at the recommended intervals in the maintenance schedule. Follow the steel tubing (pipe) from the master cylinder to the flexible hose fitting at each wheel. If a section of the tubing is found to be damaged, replace the entire section with tubing of the same type (steel, not copper), size, shape, and length. When installing a new section of brake tubing, flush clean brake fluid or denatured alcohol through the system to remove any dirt or foreign material from the line. Be sure to flare both ends to provide sound, leak-proof connections. When bending the tubing to fit the underbody contours, be careful not to kink or crack the line. Torque all hydraulic connections to 10-15 ft. lbs. (14-20 Nm).

    Check the flexible brake hoses that connect the steel tubing to each wheel cylinder. Replace the hose if it shows any signs of softening, cracking, or other damage. When installing a new front brake hose, position the hose to avoid contact with other chassis parts. Place a new copper gasket over the hose fitting and thread the hose assembly into the front wheel cylinder or use the banjo bolt to secure it to the caliper, as applicable. A new rear brake hose must be positioned clear of the exhaust pipe or shock absorber. Thread the hose into the rear brake tube connector. When installing either a new front or rear brake hose, engage the opposite end of the hose to the bracket on the frame. Install the horseshoe type retaining clip and connect the tube to the hose with the tube fitting nut.

    Always bleed the system after hose or line replacement. Before bleeding, make sure that the master cylinder is topped up with high temperature, extra heavy duty fluid of at least SAE 70R3 quality.

    REMOVAL & INSTALLATION



    Brake Hose
    1. Raise the end of the vehicle which contains the hose to be repaired, then support the vehicle safely using jackstands.
    2.  
    3. If necessary, remove the wheel for easier access to the hose.
    4.  
    5. Note the hose routing to assure correct installation.
    6.  
    7. Disconnect the hose from the wheel cylinder or caliper and plug the opening to avoid system contamination or excessive fluid loss.
    8.  
    9. Disconnect the hose from the brake line and plug the openings to avoid excessive fluid loss or contamination.
    10.  

    To install:
    1. Install the brake hose to the brake line, then make sure that the line is routed properly as noted during removal.
    2.  
    3. Tighten all hydraulic connections to 10-15 ft. lbs. (14-20 Nm).
    4.  
    5. Properly bleed the brake system, then check the connections for leaks.
    6.  
    7. Remove the supports and carefully lower the vehicle.
    8.  

    Brake Line

    There are 2 options available when replacing a brake line. The first, and probably most preferable, is to replace the entire line using a line of similar length which is already equipped with machined flared ends. Such lines are usually available from auto parts stores and usually require only a minimum of bending in order to properly fit then to the vehicle. The second option is to bend and flare the entire replacement line (or a repair section of line) using the appropriate tools.

    Buying a line with machined flares is preferable because of the time and effort saved, not to mention the cost of special tools if they are not readily available. Also, machined flares are of a higher quality than those produced by hand flaring tools or kits.

    1. Raise the end of the vehicle which contains the hose to be repaired, then support the vehicle safely using jackstands.
    2.  
    3. Remove the components necessary for access to the brake line which is being replaced.
    4.  
    5. Disconnect the fittings at each end of the line, then plug the openings to prevent system contamination or excessive fluid loss.
    6.  
    7. Trace the line from 1 end to the other and disconnect the line from any retaining clips, then remove the line from the vehicle.
    8.  

    To install:
    1. Try to obtain a replacement line that is the same length as the line that was removed. If the line is longer, you will have to cut it and flare the end, or if you have decided to repair a portion of the line, see the procedure on brake line flaring, later in this section.
    2.  
    3. Use a suitable tubing bender to make the necessary bends in the line. Work slowly and carefully; try to make the bends look as close as possible to those on the line being replaced.
    4.  

    When bending the brake line, be careful not to kink or crack the line. If the brake line becomes kinked or cracked, it must be replaced.

    1. Before installing the brake line, flush it with brake fluid to remove any dirt or foreign material.
    2.  
    3. Install the line into the vehicle. Be sure to attach the line to the retaining clips, as necessary. Make sure the replacement brake line does not contact any components that could rub the line and cause a leak.
    4.  
    5. Connect the brake line fittings, then tighten all hydraulic connections to 10-15 ft. lbs. (14-20 Nm).
    6.  
    7. Properly bleed the brake system and check for leaks.
    8.  
    9. Install any removed components, then remove the supports and carefully lower the vehicle.
    10.  

    BRAKE LINE FLARING



    Use only brake line tubing approved for automotive use; never use copper tubing. Whenever possible, try to work with brake lines that are already cut to the length needed. These lines are available at most auto parts stores and have machine made flares, the quality of which is hard to duplicate with most of the available inexpensive flaring kits.

    When the brakes are applied, there is a great deal of pressure developed in the hydraulic system. An improperly formed flare can leak with a resultant loss of stopping power. If you have never formed a double-flare, take time to familiarize yourself with the flaring kit; practice forming double-flares on scrap tubing until you are satisfied with the results.

    The following procedure applies to a standard GM flaring kit, but should be similar to commercially available brake-line flaring kits. If these instructions differ in any way from those in your kit, follow the instructions in the kit.

    1. Determine the length necessary for the replacement or repair and allow an additional 1 / 8 in. (3.2mm) for each flare. Select a length of tubing according to the repair/replacement charts in the figure, then cut the brake line to the necessary length using an appropriate saw. Do not use a tubing cutter.
    2.  
    3. Square the end of the tube with a file and chamfer the edges. Remove burrs from the inside and outside diameters of the cut line using a deburring tool.
    4.  
    5. Install the required fittings onto the line.
    6.  
    7. Install the flaring tool, into a vice and install the handle into the operating cam.
    8.  
    9. Loosen the die clamp screw and rotate the locking plate to expose the die carrier opening.
    10.  
    11. Select the required die set and install in the carrier with the full side of either half facing clamp screw and counter bore of both halves facing punch turret.
    12.  
    13. Insert the prepared line through the rear of the die and push forward until the line end is flush with the die face.
    14.  
    15. Make sure the rear of both halves of the die rest against the hexagon die stops, then rotate the locking plate to the fully closed position and clamp the die firmly by tightening the clamp screw.
    16.  
    17. Rotate the punch turret until the appropriate size points towards the open end of the line to be flared.
    18.  
    19. Pull the operating handle against the line resistance in order to create the flare, then return the handle to the original position.
    20.  
    21. Release the clamp screw and rotate the locking plate to the open position.
    22.  
    23. Remove the die set and line, then separate by gently tapping both halves on the bench. Inspect the flare for proper size and shape.
    24.  
    25. If necessary, repeat Steps 2-12 for the other end of the line or for the end of the line which is being repaired.
    26.  

     
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