GM Century/Lumina/Grand Prix/Intrigue 1997-2000

Brake Hoses and Pipes

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CAUTION
Always use double walled steel brake lines when replacing rusted or damaged brake lines. The use of any other tubing is not approved and may cause brake failure. Carefully route and retain replacement brake lines. Always use the correct fasteners and the original location for replacement brake pipes. Failure to properly route and retain brake lines may cause damage to the brake lines and cause brake system failure, resulting in possible personal injury.

The steel brake lines on these vehicles use what is called an I.S.O. Flare. This is different from the flare used on American vehicles for many years. If a brake line is damaged and requires replacement, you must obtain a replacement brake line with the correct flare. Most automotive parts stores stock straight lengths of steel brake line, already flared, with the correct fittings installed. Brake line replacement requires obtaining a piece of brake line as close in length to the original as possible. The brake line must be of the correct diameter and flare. The replacement length of brake line is carefully bent to conform to the shape of the original brake line. GM specifies that a clearance of 3 / 4 inch be maintained from all moving or vibrating components.



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Fig. These vehicles use steel brake lines with an I.S.O. Flare. Replacement brake lines must have this flare of the system will leak



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Fig. ABS systems require a considerable amount of steel brake lines to connect all components



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Fig. Typical rear brake line routing-Buick shown, others similar



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Fig. The tight underhood space constraints of front wheel drive vehicles equipped with ABS means brake lines must be carefully routed and secured

One of the major causes of brake line replacement is twisting off or otherwise damaging a piece of brake line when replacing other components. For example, when replacing a rear wheel cylinder, if the brake line is rusted, loosening the brake line fitting backs the fitting over rusted portions of the brake line. This binds up the fitting so it seizes on the brake line. Continuing to loosen the brake line fitting usually results in snapping off the brake line, requiring replacement of that section of brake line. Many technicians take the time to polish off any rust and corrosion from the brake line next to the fitting, using fine emery cloth or crocus cloth, then using a penetrating oil to loosen the brake line fitting. The time spent cleaning the brake line before attempting to loosen the fitting pays off by saving the original brake line.

Another condition requiring brake line replacement is when the fittings are damaged. This is almost always caused by using the wrong wrench. Brake line wrenches (sometimes called Flare Nut Wrenches) should be used. These wrenches wrap around the fitting, grasping it on five of the six wrench flats on the fitting. This reduces (but doesn't eliminate) the chance of rounding off the fitting's corners so that it cannot be removed, or, if removed, cannot be adequately tightened at installation. Brake line wrenches are available at most all auto supply stores, in both standard and metric sizes.

Your GM W-Body vehicle also uses brake hoses to carry the brake fluid to parts that are in motion, mainly the front and rear brakes which move with the independent suspension. Generally, brake hoses give little trouble but should be inspected at least twice a year. Check the brake hoses for road hazard damage, crack, chafing of the outer cover, leaks, blisters and for proper routing and mounting. A light and mirror may be needed for an adequate inspection. If any of these conditions are found, it will be necessary to replace the brake hose.


NOTE
Never allow components to hang from the flexible brake hoses as damage to the hoses may occur. Some brake hoses have protective rings or covers to prevent direct contact of the hose with other chassis parts. Besides causing possible structural damage to the hose, excessive tension could cause the hose rings to move out of proper locations.

REMOVAL & INSTALLATION



Front Brake Hoses & Lines
  1. Raise the vehicle and support with safety stands.
  2.  
  3. Remove the front wheel assembly.
  4.  
  5. Clean all dirt and foreign material from the brake hose and fitting.
  6.  
  7. Remove steel brake line from the brake hose at the bracket. Use brake line (flare nut) and back-up wrenches to avoid fitting damage. Generally, one wrench is used to hold the brake hose fitting stationary while another is used to loosen the fitting at the bodyside steel brake line.
  8.  
  9. Remove the brake hose retainer at the mounting bracket. This is usually a U-shaped clip that slides off the end of the brake hose, releasing it from the bracket. Remove the hose from the bracket.
  10.  
  11. Most caliper installations of these vehicle use a "banjo" fitting on the caliper end of the brake hose with a special bolt that goes through the fitting, into the caliper. Remove the inlet fitting bolt at the caliper. There should be two copper sealing washers, one on top of the banjo fitting and one under the fitting. GM recommends that these washers be replaced.
  12.  



Click image to see an enlarged view

Fig. Front disc brake caliper and brake hose arrangement

To install:

  1. Clean all parts well. Lubricate the caliper bolt threads with clean brake fluid. Using new copper washers, assemble the banjo fitting to the caliper. Carefully tighten the bolt to 30-33 ft. lbs. (40-44 Nm).
  2.  
  3. With the vehicle weight on the suspension, install the brake hose to the bracket and install the U-shaped brake hose retainer clip. Make sure there are NO kinks in the hose. Many brake hoses have a paint stripe on them as a visual aid to help you make sure the hose is not twisted at installation.
  4.  
  5. Hold the brake hose fitting stationary and install the bodyside steel brake line fitting into the brake hose. Tighten with your fingers to make sure the fitting is not cross-threaded, which will cause a fluid leak. When satisfied with the installation of the fitting, use your brake line wrenches to tighten the fitting to 11-15 ft. lbs. (15-20 Nm).
  6.  


WARNING
Make sure the hose is NOT kinked or touching any part of the frame or suspension after installation. These conditions may cause the hose to fail prematurely.

  1. Check the hose after turning the steering wheel extreme right and then extreme left. If the hose is tight or touching anything, make the proper adjustments.
  2.  
  3. Install the wheel and tire assembly.
  4.  
  5. Carefully lower the vehicle. The brake system must be bled as outlined later in this information.
  6.  


CAUTION
Do not move the vehicle until a firm brake pedal is obtained. Failure to obtain a firm pedal before moving the vehicle may result in personal injury.

  1. Verify that a firm brake pedal has been obtained before moving the vehicle.
  2.  

Rear Brake Hoses & Lines
WITH REAR DISC BRAKES
  1. Raise the vehicle and support with safety stands.
  2.  
  3. Remove the rear wheel and tire assembly.
  4.  
  5. Clean all dirt and foreign material from the brake hose and fitting.
  6.  
  7. The rear caliper brake hose is attached to the body with a bracket near the rear strut, that bolts to both the body and the inboard end of the brake hose. Remove the attaching bolt.
  8.  
  9. Remove steel brake line from the brake hose at the bracket. Use brake line (flare nut) and back-up wrenches to avoid fitting damage. Generally, one wrench is used to hold the brake hose fitting stationary while another is used to loosen the fitting at the bodyside steel brake line. Use care not to bend the brake line or the bracket.
  10.  
  11. Remove the brake hose retainer at the mounting bracket. Remove the hose from the bracket.
  12.  
  13. Most caliper installations of these vehicle use a "banjo" fitting on the caliper end of the brake hose with a special bolt that goes through the fitting, into the caliper. Remove the inlet fitting bolt at the caliper. There should be two copper sealing washers, one on top of the banjo fitting and one under the fitting. GM recommends that these washers be replaced.
  14.  



Click image to see an enlarged view

Fig. Rear disc brake caliper and hose arrangement

To install:

  1. Clean all parts well. Lubricate the caliper bolt threads with clean brake fluid. Using new copper washers, assemble the banjo fitting to the caliper. Carefully tighten the bolt to 20 ft. lbs. (27 Nm).
  2.  
  3. With the vehicle's weight on the suspension, install the brake hose to the bracket. The hose fitting must align with a notch in the bracket. Make sure there are NO kinks in the hose. Many brake hoses have a paint stripe on them as a visual aid to help you make sure the hose is not twisted at installation.
  4.  
  5. Hold the brake hose fitting stationary and install the bodyside steel brake line fitting into the brake hose. Tighten with fingers to make sure the fitting is not crossthreaded which will cause a fluid leak. When satisfied with the installation of the fitting, use your brake line wrenches to tighten the fitting to 20 ft. lbs. (27 Nm).
  6.  


WARNING
Make sure the hose is NOT kinked or touching any part of the frame or suspension after installation. These conditions may cause the hose to fail prematurely.

  1. Install the wheel and tire assembly.
  2.  
  3. Carefully lower the vehicle. The brake system must be bled as outlined later in this information.
  4.  


CAUTION
Do not move the vehicle until a firm brake pedal is obtained. Failure to obtain a firm pedal before moving the vehicle may result in personal injury.

  1. Verify that a firm brake pedal has been obtained before moving the vehicle.
  2.  

WITH REAR DRUM BRAKES

Rear drum brakes have flexible rubber hoses from the body to a bracket bolted to the rear struts. A short length of steel brake line connects the wheel-end of the hoses to the wheel cylinders.

  1. Raise the vehicle and support with safety stands.
  2.  
  3. Remove the rear wheel assembly.
  4.  
  5. Clean all dirt and foreign material from the brake hose and fittings at both ends of the brake hose.
  6.  
  7. The rear drum brake hoses are attached to the body with a bracket on one end and at the wheel-end, attached to a bracket bolted to the rear of the strut. Remove steel brake lines from both ends of the rear drum brake hose. Use brake line (flare nut) and back-up wrenches to avoid fitting damage. Generally, one wrench is used to hold the brake hose fitting stationary while another is used to loosen the fitting at the bodyside steel brake line. Use care not to bend the brake line or the bracket.
  8.  
  9. Remove the brake hose retainers at the mounting brackets. Remove the hose from the bracket.
  10.  



Click image to see an enlarged view

Fig. Rear brake hose, brake line and bracket arrangement for vehicles equipped with rear drum brakes

To install:

  1. Clean all parts well. With the vehicle's weight on the suspension, install the brake hose to the bracket. The hose fitting must align with a notch in the bracket. Make sure there are NO kinks in the hose. Many brake hoses have a paint stripe on them as a visual aid to help you make sure the hose is not twisted at installation.
  2.  
  3. Hold the brake hose fitting stationary and install the bodyside and wheel-end steel brake line fittings into the brake hose. Tighten with fingers to make sure the fittings are not crossthreaded which will cause a fluid leak. When satisfied with the installation of the fitting, use your brake line wrenches to tighten the fitting to 20 ft. lbs. (27 Nm).
  4.  


WARNING
Make sure the hose is NOT kinked or touching any part of the frame or suspension after installation. These conditions may cause the hose to fail prematurely.

  1. Install the wheel and tire assembly.
  2.  
  3. Carefully lower the vehicle. The brake system must be bled as outlined in this section.
  4.  

 
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