GM Blazer/Jimmy/Typhoon/Bravada 1983-1993 Repair Guide

Brake Pipes and Hoses

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REMOVAL & INSTALLATION



You will need to use new brass gaskets when installing hoses with banjo fittings.

Flexible Hoses

See Figure 1

Flexible hoses are usually installed between the frame-to-front calipers and the frame-to-rear differential, though they may be used elsewhere on some applications. Commonly, flexible hoses are used at points on the vehicle where suspension travel would damage or break a solid metal pipe.

  1. Using a wire brush and a cloth, clean the dirt and/or grease from both ends of the hose fittings.
  2.  
  3. Disconnect the steel pipe fitting at the end of the flexible hose.
  4.  

Because the flexible hose is designed to move slightly with the suspension, routing is VERY important. Before disconnecting a hose take note of how it is routed in order to assure proper installation.



Click image to see an enlarged view

Fig. Fig. 1: Common flexible brake hose mounting - early model vehicles

  1. To remove the brake hose from the front brake caliper or the rear differential, perform the following procedures:
    1. Remove the brake hose-to-frame bracket retaining clip.
    2.  
    3. Remove the brake hose-to-brake caliper or differential junction block bolt.
    4.  
    5. Remove the brake hose and the gaskets from the vehicle.After disconnecting the brake hose, be sure to cap or plug all openings in order to prevent system contamination or excessive fluid loss.
    6.  

  2.  
  3. Clean and inspect the brake hose(s) for cracking, chafing or road damage; replace the hose(s) if any signs are observed.
  4.  

To install:
  1. Route the hose as noted during removal. Make sure the line is not kinked or twisted.
  2.  

Be sure that the hoses do not make contact with any of the suspension components.

  1. Connect the hose to the caliper or junction block and secure using the retaining bolt and NEW gaskets. Tighten the bolt to 32 ft. lbs. (44 Nm) on caliper fittings or to 13 ft. lbs. (17 Nm) on junction block fittings.
  2.  
  3. Make sure the hose is still properly routed and secure any retaining clips or brackets.
  4.  
  5. Connect the line to the steel pipe fitting, then tighten the fitting to 1 ft. lbs. (29 Nm).
  6.  
  7. Properly bleed the hydraulic brake system at the wheel cylinder or caliper downstream of the hose that was replaced.
  8.  

Steel Pipes

See Figure 2

When replacing the steel brake pipes, always use double-walled steel piping which is designed to withstand high pressure and resist corrosion. Also, it is important to make sure that the pipe is of the same size to assure both a proper fit and proper brake operation.


CAUTION
Never use copper tubing. It is subject to fatigue, cracking, and/or corrosion, which will result in brake line failure.

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 requires the use of the a tube cutter tool No. J-23533 and a flaring tool No. J-23530 or their equivalents.

  1. Disconnect the steel brake pipe(s) and measure the old part to determine the shape and length of the replacement.
  2.  
  3. Remove the steel brake pipe from the vehicle. Be sure to remove any retaining clips before attempting to remove the pipe.
  4.  
  5. Obtain a new steel pipe (of proper type and size), then cut the pipe to length using a tube cutter such as J-23533 or equivalent. The pipe should be cut to approximately the same length of the old pipe, but be sure to add an additional 1 / 8 in. (3mm) for each flare.
  6.  



Click image to see an enlarged view

Fig. Fig. 2: Single and double flare tube ends

  1. 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.
  2.  

Be sure to install the correct pipe fittings onto the tube before forming any flares.

  1. Use a flaring tool such as J-23530 or equivalent to form double flares on the ends of the pipes. Be sure to follow the tool manufacturer's instructions closely.
  2.  
  3. Use a small pipe bending tool to properly shape the pipe to match the contour of the old component.
  4.  
  5. Install the pipe and tighten the fittings. Make sure the pipe is in the same position as the original and will not contact any suspension or other moving parts.
  6.  
  7. Properly bleed the hydraulic brake system.
  8.  

 
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