No Brake Pressure in Pedal: There Is No Pressure in My Brake Pedal…

No Brake Pressure in Pedal: There Is No Pressure in My Brake Pedal...

If you can pump up the pedal when it’s off but it goes to the floor slowly with engine off or quickly with engine running, I suspect either there is a leak or the master cylinder is bad.

Try this. With the engine off, pump up the brakes and hold steady pressure on the pedal. Does it slowly go to the floor? If so, the MC is bad.

Confirm the brake fluid is full. If it is, then there are no leaks. At that point, replace the master cylinder.

Take a look through this link:

https://tonupboys.com/articles/brake-pedal-goes-to-the-floor

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Here are the directions specific to your vehicle. The attached pics correlate with the directions. However, before replacing this, reconfirm there are no leaks under the vehicle, at the MC area, or at any of the wheels.

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2003 GMC Truck S15/T15 Sonoma P/U 2WD V6-4.3L VIN X
Master Cylinder Replacement
Vehicle Brakes and Traction Control Hydraulic System Brake Master Cylinder Service and Repair Procedures Master Cylinder Replacement
MASTER CYLINDER REPLACEMENT
Master Cylinder Replacement

Removal Procedure

Notice: Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Service Precautions.

1. Apply the parking brake and block the wheels.
2. Disconnect the brake pipes from the master cylinder.

Important: Install a rubber cap or plug to the exposed brake pipe fitting ends in order to prevent brake fluid loss and contamination.

pic 1

3. Plug the open brake pipe ends.

pic 2

4. Remove the master cylinder nuts and bolts.
5. Remove the master cylinder from the vehicle.
6. Drain the master cylinder reservoir of all the brake fluid.

Installation Procedure

pic 3

1. Bench bleed the master cylinder.

pic 4

2. Install the master cylinder to the vehicle.

Notice: Refer to Fastener Notice in Service Precautions.

3. Install the master cylinder bolts and nuts.
Tighten the nuts to 36 Nm (27 ft. lbs.).

pic 5

4. Connect the brake pipes to the master cylinder.
Tighten the pipe nuts to 30 Nm (22 ft. lbs.).
5. Bleed the hydraulic brake system.

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Here are the directions for bleeding the system.

2003 GMC Truck S15/T15 Sonoma P/U 2WD V6-4.3L VIN X
Hydraulic Brake System Bleeding (Manual)
Vehicle Brakes and Traction Control Hydraulic System Brake Bleeding Service and Repair Procedures Hydraulic Brake System Bleeding (Manual)
HYDRAULIC BRAKE SYSTEM BLEEDING (MANUAL)
Hydraulic Brake System Bleeding (Manual)

Notice: When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

Notice: Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Service Precautions.

1. Place a clean shop cloth beneath the brake master cylinder to prevent brake fluid spills.
2. With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.
3. If you have performed a brake master cylinder bench bleeding on this vehicle, or if you disconnected the brake pipes from the master cylinder, you must perform the following steps:
3.1. Ensure that the brake master cylinder reservoir is full to the maximum-fill level. If necessary add Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. If removal of the reservoir cap and diaphragm is necessary, clean the outside of the reservoir on and around the cap prior to removal.
3.2. With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder.
3.3. Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder.
3.4. Reconnect the brake pipe to the master cylinder port and tighten securely.
3.5. Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
3.6. Loosen the same brake pipe to purge air from the open port of the master cylinder.
3.7. Tighten the brake pipe, then have the assistant slowly release the brake pedal.
3.8. Wait 15 seconds, then repeat steps 3.3-3.7 until all air is purged from the same port of the master cylinder.
3.9. With the front brake pipe installed securely to the master cylinder – after all air has been purged from the front port of the master cylinder – loosen and separate the rear brake pipe from the master cylinder, then repeat steps 3.3-3.8.
3.10. After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.
4. Fill the brake master cylinder reservoir with Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. Ensure that the brake master cylinder reservoir remains at least half-full during this bleeding procedure. Add fluid as needed to maintain the proper level.
Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.
5. Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.
6. Install a transparent hose over the end of the bleeder valve.
7. Submerge the open end of the transparent hose into a transparent container partially filled with Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
8. Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
9. Loosen the bleeder valve to purge air from the wheel hydraulic circuit.
10. Tighten the bleeder valve, then have the assistant slowly release the brake pedal.
11. Wait 15 seconds, then repeat steps 8-10 until all air is purged from the same wheel hydraulic circuit.
12. With the right rear wheel hydraulic circuit bleeder valve tightened securely – after all air has been purged from the right rear hydraulic circuit – install a proper box-end wrench onto the LEFT REAR wheel hydraulic circuit bleeder valve.
13. Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
14. With the left rear wheel hydraulic circuit bleeder valve tightened securely – after all air has been purged from the left rear hydraulic circuit – install a proper box-end wrench onto the RIGHT FRONT wheel hydraulic circuit bleeder valve.
15. Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
16. With the right front wheel hydraulic circuit bleeder valve tightened securely – after all air has been purged from the right front hydraulic circuit – install a proper box-end wrench onto the LEFT FRONT wheel hydraulic circuit bleeder valve.
17. Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
18. After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.
19. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
20. Slowly depress and release the brake pedal. Observe the feel of the brake pedal.
21. If the brake pedal feels spongy, repeat the bleeding procedure again. If the brake pedal still feels spongy after repeating the bleeding procedure, perform the following steps:
21.1. Inspect the brake system for external leaks.
21.2. Pressure bleed the hydraulic brake system in order to purge any air that may still be trapped in the system.
22. Turn the ignition key ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated.

Important: If the brake system warning lamp remains illuminated, DO NOT allow the vehicle to be driven until it is diagnosed and repaired.

23. If the brake system warning lamp remains illuminated, refer to Symptoms – Hydraulic Brakes.

Let me know if this helps.

Joe
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No Hi, If you can pump up the pedal point when it ‘s off but it goes to the floor slowly with locomotive off or quickly with engine running, I suspect either there is a leak or the master cylinder is bad.Try this. With the engine off, pump up the brakes and hold steady pressure on the pedal. Does it slowly go to the floor ? If indeed, the MC is bad.Confirm the bracken fluid is wax. If it is, then there are no leaks. At that distributor point, replace the overcome cylinder.Take a look through this connect : _________________________________________________Here are the directions specific to your fomite. The attached pics correlate with the directions. however, before replacing this, reconfirm there are no leaks under the vehicle, at the MC area, or at any of the wheels.________________________________________________2003 GMC Truck S15/T15 Sonoma P/U 2WD V6-4.3L VIN XMaster Cylinder ReplacementVehicle Brakes and Traction Control Hydraulic System Brake Master Cylinder Service and Repair Procedures Master Cylinder ReplacementMASTER CYLINDER REPLACEMENTMaster Cylinder ReplacementRemoval ProcedureNotice : refer to Brake Fluid Effects on Paint and electric Components Notice in Service Precautions.1. Apply the parking brake and block the wheels.2. Disconnect the brake pipes from the chief cylinder.Important : Install a arctic detonator or punch to the exposed brake pipe fitting ends in orderliness to prevent brake fluent loss and contamination.pic 13. Plug the open brake pipe ends.pic 24. Remove the master cylinder nuts and bolts.5. Remove the master cylinder from the vehicle.6. Drain the master cylinder reservoir of all the brake fluid.Installation Procedurepic 31. Bench bleed the overcome cylinder.pic 42. Install the overlord cylinder to the vehicle.Notice : refer to Fastener Notice in Service Precautions.3. Install the master cylinder bolts and nuts.Tighten the nuts to 36 Nm ( 27 foot. pound. ) .pic 54. Connect the brake pipes to the passkey cylinder.Tighten the pipe nuts to 30 Nm ( 22 foot. lbs. ) .5. Bleed the hydraulic brake system._______________________________________________Here are the directions for bleeding the system.2003 GMC Truck S15/T15 Sonoma P/U 2WD V6-4.3L VIN XHydraulic Brake System Bleeding ( Manual ) Vehicle Brakes and Traction Control Hydraulic System Brake Bleeding Service and Repair Procedures Hydraulic Brake System Bleeding ( Manual ) HYDRAULIC BRAKE SYSTEM BLEEDING ( MANUAL ) Hydraulic Brake System Bleeding ( Manual ) Notice : When adding fluid to the brake passkey cylinder reservoir, use alone Delco Supreme 11, GM P/N 12377967 ( canadian P/N 992667 ), or equivalent DOT-3 brake fluid from a clean, sealed bracken fluid container. The use of any type of fluid early than the recommend type of brake fluid, may cause contaminant which could result in damage to the inner rubber seals and/or rubber eraser linings of hydraulic brake organization components.Notice : mention to Brake Fluid Effects on Paint and electric Components Notice in Service Precautions.1. Place a clean workshop cloth beneath the bracken master cylinder to prevent bracken fluid spills.2. With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake bicycle effort increases importantly, in order to deplete the brake booster ability reserve.3. If you have performed a brake master cylinder bench bleeding on this vehicle, or if you disconnected the bracken pipes from the master cylinder, you must perform the succeed steps:3.1. see that the brake maestro cylinder reservoir is full to the maximum-fill horizontal surface. If necessary add Delco Supreme 11, GM P/N 12377967 ( canadian P/N 992667 ), or equivalent DOT-3 bracken fluid from a clean, sealed brake fluid container. If removal of the reservoir capital and diaphragm is necessary, clean the outside of the reservoir on and around the cap anterior to removal.3.2. With the buttocks brake pipe installed securely to the chief cylinder, relax and separate the front brake pipe from the front larboard of the brake master cylinder.3.3. Allow a little amount of brake fluid to gravity shed blood from the open port of the dominate cylinder.3.4. Reconnect the brake pipe to the passkey cylinder port and tighten securely.3.5. Have an assistant slowly depress the brake pedal in full and maintain steadily press on the pedal.3.6. Loosen the same brake pipe to purge air from the unfold port of the maestro cylinder.3.7. Tighten the brake pipe, then have the adjunct lento release the bracken pedal.3.8. Wait 15 seconds, then repeat steps 3.3-3.7 until all air is purged from the same port of the master cylinder.3.9. With the front brake shriek installed securely to the dominate cylinder – after all vent has been purged from the front port of the headmaster cylinder – loosen and separate the raise bracken pipe from the master cylinder, then repeat steps 3.3-3.8.3.10. After completing the final chief cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are by rights tightened.4. Fill the bracken master cylinder reservoir with Delco Supreme 11, GM P/N 12377967 ( canadian P/N 992667 ), or equivalent DOT-3 brake fluid from a clean and jerk, sealed bracken fluid container. see that the brake master cylinder reservoir remains at least half-full during this bleeding procedure. Add fluid as needed to maintain the proper level.Clean the outdoor of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.5. Install a proper box-end wrench onto the correct REAR wheel hydraulic circuit hemophiliac valve.6. Install a diaphanous hosiery over the end of the hemophiliac valve.7. Submerge the open end of the diaphanous hose into a guileless container partially filled with Delco Supreme 11, GM P/N 12377967 ( canadian P/N 992667 ), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.8. Have an adjunct slowly depress the bracken pedal fully and maintain steady pressure on the pedal.9. Loosen the hemophiliac valve to purge air from the roulette wheel hydraulic circuit.10. Tighten the hemophiliac valve, then have the assistant lento release the brake pedal.11. Wait 15 seconds, then repeat steps 8-10 until all vent is purged from the lapp wheel hydraulic circuit.12. With the right buttocks wheel hydraulic tour hemophiliac valve tightened securely – after all air has been purged from the right raise hydraulic circumference – install a proper box-end twist onto the LEFT REAR wheel hydraulic lap hemophiliac valve.13. Install a guileless hosiery over the end of the hemophiliac valve, then repeat steps 7-11.14. With the left raise wheel hydraulic circuit hemophiliac valve tightened securely – after all breeze has been purged from the leave raise hydraulic circuit – install a proper box-end twist onto the RIGHT FRONT wheel hydraulic circuit hemophiliac valve.15. Install a transparent hosiery over the end of the hemophiliac valve, then repeat steps 7-11.16. With the right field front man wheel hydraulic tour hemophiliac valve tightened securely – after all air has been purged from the right front hydraulic circuit – install a proper box-end twist onto the LEFT FRONT wheel hydraulic racing circuit hemophiliac valve.17. Install a diaphanous hose over the end of the hemophiliac valve, then repeat steps 7-11.18. After completing the final bicycle hydraulic circuit shed blood routine, ensure that each of the 4 rack hydraulic circuit hemophiliac valves are by rights tightened.19. Fill the brake victor cylinder reservoir to the maximum-fill degree with Delco Supreme 11, GM P/N 12377967 ( canadian P/N 992667 ), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.20. Slowly depress and release the brake pedal point. Observe the spirit of the brake pedal.21. If the brake pedal feels spongy, repeat the bleeding procedure again. If the brake pedal still feels spongy after repeating the bleed procedure, perform the following steps:21.1. Inspect the brake system for external leaks.21.2. blackmail bleed the hydraulic brake system in order to purge any air that may still be trapped in the system.22. Turn the ignition samara ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated.Important : If the brake system warning lamp remains illuminate, DO NOT allow the vehicle to be driven until it is diagnosed and repaired.23. If the bracken system warning lamp remains illuminate, refer to Symptoms – hydraulic Brakes.Let me know if this helps.Joe

source : https://tonupboys.com
Category : Car Brakes