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john, Auto, ATV, Sleds, Bikes, Tractors
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Experience:  26 years of mechanics experience
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1999 GMC: the caliper rotor and pads...cant seem to get the brakes

Resolved Question:

how do you bleed the brakes on a 99 jimmy i just replaced the caliper rotor and pads...cant seem to get the brakes bled

Optional Information:
1999 GMC Jimmy 4.3

Already Tried:
I have replace the back rotors, calipers and pads...cant get the brakes bled





Submitted: 8 years ago.
Category: Car
Expert:  Emily replied 8 years ago.
Start at farthest wheel away and work your way closer to the master cylinder. Try bleeding them without running the engine you may have better luck. Did you bench bleed the calipers before installation?
Customer: replied 8 years ago.
Reply to Emily's Post: I was told I did not have to bench bleed the calipers...?I tried both w/ engine on and off...now I am being told I need to ajust the e-brake...gosh I am lost!!!!
Expert:  john replied 8 years ago.

Hydraulic Brake System Bleeding



NoticeJust let me know if you need any more help.


Brake fluid will damage electrical connections and painted surfaces. Use shop cloths, suitable containers, and fender covers to prevent brake fluid from contacting these areas. Always re-seal and wipe off brake fluid containers to prevent spills.



If air has entered the hydraulic brake system, bleed the system. You may need to bleed the hydraulic brake system at all four wheels due to one of the following conditions:



  • Air entered the system due to a low fluid level.
  • The brake pipes have been disconnected at the master cylinder.
  • The brake pipes have been disconnected at the combination valve.
  • The brake pipes have been disconnected at the Brake Pressure Modulator Valve (BPMV).

If a pipe is disconnected at one wheel, then only bleed that wheel.


If the master cylinder has been removed, bench bleed the master cylinder before installing it on the vehicle in order to reduce the time required to bleed the system. Refer to Master Cylinder Bench Bleeding .


If the BPMV has been replaced or has air trapped in it, refer to Brake Pressure Modulator Valve (BPMV) Replacement in Antilock Brake System.


Manual Bleeding

    Tools Required
  • J 28434 Wheel Cylinder Bleeder Wrench
  • J 21472 Brake Bleeder Wrench


  1. Apply the brakes several times with the ignition OFF in order to relieve the brake vacuum reserve.
  2. Fill the master cylinder reservoirs with DOT 3 motor vehicle brake fluid.
  3. Maintain the fluid level during bleeding.
  4. If the master cylinder has air in the bore, bleed the master cylinder using the following procedure:

    1. Disconnect the forward brake pipe connector at the master cylinder.
    2. Allow the brake fluid to flow from the connector port.
    3. Connect the brake pipe connector. Do not tighten the brake pipe connector.
    4. Slowly apply the brake pedal and allow the air to bleed from the loose connector.
    5. Tighten the connector before releasing the brake pedal.
    6. Wait 15 seconds.
    7. Repeat this sequence, including the 15 second wait, until all air is purged from the master cylinder bore.
    8. Repeat this procedure for the rear brake pipe after you purge all the air from the forward pipe connection.

  5. If the brake pressure modulator valve of the antilock brake system is replaced or if you suspect that air is trapped inside, bleed the brake pressure modulator valve next. Refer to Brake Pressure Modulator Valve (BPMV) Replacement in Antilock Brake System.
  6. Follow this sequence if it is necessary to bleed all four wheels:

    1. Right rear wheel cylinder or caliper.
    2. Left rear wheel cylinder or caliper.
    3. Right front wheel caliper.
    4. Left front wheel caliper.

  7. Use J 28434 to bleed the wheel cylinders.

    1. Place the hex end of the wrench over the wheel cylinder bleeder valve.
    2. Immerse the opposite end of the hose into a clear container partially filled with clean brake fluid.

  8. Use J 21472 to bleed the calipers.

    1. Place the proper size hex end of the wrench over the caliper bleeder valve.
    2. Place a clear tube over the caliper bleeder valve.
    3. Immerse the opposite end of the hose into a clear container partially filled with clean brake fluid.

  9. Slowly apply the brake pedal one time and hold.
  10. Loosen the bleeder valve in order to purge the air from the wheel cylinder or caliper.
  11. Tighten the bleeder valve and slowly release the brake pedal.
  12. Wait 15 seconds.


    Notice


    Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.



  13. Repeat this sequence, including the 15-second wait, until all air is purged from the wheel cylinder or caliper. Tighten

    Tighten the bleeder valve to 7 N·m (62 lb in).


  14. Repeat steps 7-13 at each wheel until the brake system is bled.
  15. Clean any brake fluid off the vehicle that may have gotten on it during the bleeding procedure.
  16. Inspect the brake pedal for sponginess, and inspect the brake warning lamp for an indication of unbalanced pressure. Repeat the bleeding procedure in order to correct either of these conditions.
  17. Fill the master cylinder reservoir to the proper level. Refer to Master Cylinder Reservoir Filling .

Pressure Bleeding

Use a diaphragm-type pressure bleeder. The pressure bleeder must have a rubber diaphragm between the air supply and the brake fluid. This prevents the following items from entering the hydraulic brake system:



  • Air
  • Moisture
  • Oil
  • Other contaminants

    Tools Required
  • J 35589 Master Cylinder Pressure Bleeder Adapter
  • J 39177 Combination Valve Pressure Bleeding Tool
  • J 28434 Wheel Cylinder Bleeder Wrench
  • J 21472 Brake Bleeder Wrench


  1. Fill the pressure bleeder tank at least 2/3 full of brake fluid.
  2. Charge the pressure bleeder with 140-170 kPa (20-25 psi) air pressure.
  3. Bleed the pressure bleeder each time fluid is added in order to remove any trapped air.
    Object Number: 383536  Size: SH
    Click here for detailed picture of above image.

  4. Use the J 39177 in order to depress and hold the valve stem on the combination valve.
  5. Remove the master cylinder reservoir cap and install the master cylinder pressure bleeder adapter, J 35589 , to the reservoir.
  6. If the brake pressure modulator valve of the antilock brake system is replaced, or if you suspect that air is trapped inside, bleed the brake pressure modulator valve first. Refer to Brake Pressure Modulator Valve (BPMV) Replacement in Antilock Brake System.
  7. Follow this sequence if it is necessary to bleed all four wheels:

    1. Right rear wheel cylinder or caliper.
    2. Left rear wheel cylinder or caliper.
    3. Right front wheel caliper.
    4. Left front wheel caliper.

  8. Connect the hose from the pressure bleeder to the adapter at the master cylinder.
  9. Open the tank valve.
  10. Use J 28434 to bleed the wheel cylinders.

    1. Place the hex end of the wrench over the wheel cylinder bleeder valve.
    2. Immerse the opposite end of the hose into a clear container partially filled with clean brake fluid.

  11. Use J 21472 to bleed the calipers.

    1. Place the proper size hex end of the wrench over the caliper bleeder valve.
    2. Place a clear tube over the caliper bleeder valve.
    3. Immerse the opposite end of the hose into a clear container partially filled with clean brake fluid.


    Notice


    Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.



  12. Slowly open the wheel cylinder or caliper bleeder valve at least 3/4 of a turn. Allow the fluid to flow until you see no more air in the fluid. Tighten

    Tighten the wheel cylinder or caliper bleeder valve to 7 N·m (62 lb in).


  13. Repeat steps 10-12 at each wheel until the brake system is bled.
  14. Clean any brake fluid off the vehicle that may have gotten on it during the bleeding procedure.
  15. Inspect the brake pedal for sponginess. Inspect the brake warning lamp for an indication of unbalanced pressure. Repeat the bleeding procedure in order to correct either of these conditions.
  16. Disconnect the hose from the bleeder adapter.
  17. Remove the bleeder adapter.
  18. Fill the master cylinder to the proper level. Refer to Master Cylinder Reservoir Filling .
  19. Install the master cylinder reservoir cap.
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john, Auto, ATV, Sleds, Bikes, Tractors
Category: Car
Satisfied Customers: 298
Experience: 26 years of mechanics experience
john and 9 other Car Specialists are ready to help you
Customer: replied 8 years ago.
Reply to john's Post: Hey John,
Thanks..I seem to have no pressure at the rr tire when depressing the brake pedal and holding...I loosen the bleeder but the fluid basically dribbles out...normally when I have done this in the past air and fluid would express under pressure? Was i supposed to bench bleed the calipers?
Expert:  john replied 8 years ago.
It is usually a good idea to bench bleed but since you are this far along,we can skip that.You may have a lot of air in the caliper,that is why you have pressure when your foot is on the pedal-but after cracking the bleeder-only get a dribble.Try to follow the instructions that I sent,and keep bleeding-sometimes it takes a little time.
Customer: replied 8 years ago.
Reply to john's Post: Hey John,

I am accepting your answer...great info and thank you very much...But the Pedal is spongy not firm...I will continue to bleed...It just has never taken this long before...

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