Randomly the brake pedal sticks to the floor

Hi,

I checked back through all unanswered questions and nothing is there. I'm not sure why it didn't come through to us. What is happening and how can I help?

Joe

Okay, is the brake fluid staying full? The idea that only one brake is working (rear) tells me there is either a fluid issue or the master cylinder has failed. Also, the idea that the brake pedal stays to the floor until the engine is turned off is really odd but is most likely related to a faulty vacuumed controlled brake booster.

First, try something. Do not drive the vehicle like this, but I want you to disconnect the vacuum supply to the brake booster behind the master cylinder. The brakes should become hard to press. Tell me if the pedal still sticks. Also, the idea that the pedal goes to the floor is a strong indicator that if the brake fluid is not low, the master cylinder has failed.

Take a look through this link:

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

Check to confirm there are no leaks under the vehicle and that the fluid is full. Also, disconnect the vacuum hose to the booster and see if the pedal still is sticking.

Let me know the results.
Joe

Not a problem. I will watch for your reply.

Take care,
Joe

Not a problem. The biggest concern is if the brake fluid reservoir is low or empty. Also, let me know if the brake light is on and if the vehicle has ABS.

Take care,
Joe

Dennis,

Not a problem. Take care when removing the broken bolt. Make sure you center the drill and use a quality easy out. You don't want to break that off in the bolt. They are nearly impossible to drill.

When you get to it, let me know.
Take care,
Joe

No, you should be fine. Take care and let me know how things turn out.

Joe

Can you upload a pic of the hole so I can see what you are dealing with? If it is aluminum you are dealing with, the right way is to mig weld. They make products for metal repairs, I don't know how well they can take the pressure.

Joe

Actually, that is the best thing to do. Let me know when we can get back the brake issue.

I don't know if you need them, but here are the directions for both the upper and lower. They include torque specs and tightening sequence. The attached pics correlate with the directions. I will start with the upper.

Normally, you can remove the lower without taking the upper off. However, since the lower one needs replaced, I included info related to the upper as well.
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1996 Chevy Truck S10/T10 P/U 2WD V6-4.3L VIN W
Intake Manifold Replacement (Upper)
Vehicle Engine, Cooling and Exhaust Engine Intake Manifold Service and Repair Procedures Intake Manifold Replacement (Upper)
INTAKE MANIFOLD REPLACEMENT (UPPER)
Upper Intake Manifold And Components

pic 1

Upper Intake Manifold Installation

pic 2

REMOVE OR DISCONNECT
1. Negative battery cable.
2. Drain the engine coolant.
3. Air cleaner inlet duct.
4. Wiring harness connectors and brackets.
5. Throttle linkage and bracket.
6. Fuel lines and bracket at the rear of the lower intake manifold.
7. Brake booster vacuum hose.
8. Ignition coil.
9. PCV pipe and vacuum hoses.
10. Purge solenoid and bracket.
11. Upper intake manifold bolts and manifold. Mark the location of the bolts for proper reassembly.

INSTALL OR CONNECT
1. New upper manifold gasket with sealing lines facing up.
2. Upper intake manifold. Do not pinch the injector wires between the upper and lower intake manifolds.
3. Upper intake manifold bolts and studs noting the marks made during disassembly. Tighten the bolts in two steps:
a. Tighten to 5 Nm (44 in lbs).
B. Tighten to 10 Nm (88 in lbs).

4. Purge solenoid and bracket.
5. PCV pipe and vacuum hoses.
6. Ignition coil.
7. Brake booster vacuum hose.
8. Fuel lines and bracket at the rear of the lower intake manifold.
9. Throttle linkage and bracket.
10. Wiring harness connectors and brackets.
11. Air cleaner inlet duct.
12. Negative battery cable.
13. Fill and recheck engine coolant level.
14. Inspect for leaks:
a. Turn the ignition switch to the "ON" position for 2 seconds.
B. Turn the ignition switch to the "OFF" for 10 seconds.
C. Turn the ignition switch to the "ON" position.
D. Check for fuel leaks.

_______________________________________

1996 Chevy Truck S10/T10 P/U 2WD V6-4.3L VIN W
Intake Manifold Replacement (Lower)
Vehicle Engine, Cooling and Exhaust Engine Intake Manifold Service and Repair Procedures Intake Manifold Replacement (Lower)
INTAKE MANIFOLD REPLACEMENT (LOWER)

pic 3

Applying Sealant To The Rear Of The Block

pic 4

Applying Sealant To The Front Of The Block
pic 5

Tightening Sequence

pic 6

REMOVE OR DISCONNECT
1. Negative battery cable.
2. Drain the cooling system.
3. Air cleaner intake duct.
4. Wiring harness connectors and brackets.
5. Throttle linkage and bracket.
6. Fuel lines and bracket at the rear of the lower intake manifold.
7. Vacuum hoses to upper and lower intake manifolds.
8. Distributor. Mark the housing and rotor positions for proper reassembly.
9. Upper radiator hose at the thermostat housing.
10. Heater hoses at the lower intake manifold.
11. Wiring harness and brackets.
12. Transmission oil level indicator and tube (automatic transmissions only).
13. Air conditioning compressor and bracket.
14. EGR tube, clamp, and bolt.
15. Alternator bracket bolt next to the thermostat housing.
16. Lower intake manifold bolts and manifold.
17. Clean gasket surfaces, carbon buildup and deposits from EGR and exhaust passages. Also, scale and deposits from coolant passages.
18. Inspect manifold for cracks, broken flanges and gasket surface damage.

INSTALL OR CONNECT
1. Gaskets onto the cylinder head with the port blocking plates facing the rear of the engine and the "This Side Up" stamping facing up.
2. Apply a 5 mm (1/4 inch) thick bead of Wacker T-330 RTV, GM P/N 12346192 to the front and rear sealing areas of the engine block and intake manifold. Extend the RTV bead 13 mm (0.499 inch) up the cylinder head in order to seal and retain the gaskets.
3. Lower intake manifold to the engine and apply sealer to the lower intake manifold bolts.
4. Install the lower intake manifold bolts. Tighten bolts in sequence and in three steps:
a. First sequence to 3 Nm (27 in lbs).
B. Second sequence to 12 Nm (106 in lbs).
C. Final sequence to 15 Nm (11 ft lbs).

5. Alternator bracket bolt next to the thermostat housing.
6. EGR tube, clamp, and bolt.
7. Air conditioning compressor and bracket.
8. Transmission oil level indicator and tube (automatic transmissions only).
9. Wiring harness and brackets.
10. Heater hoses at the lower intake manifold.
11. Upper radiator hose at the thermostat housing.
12. Distributor. Noting the housing and rotor positions as marked during disassembly.
13. Vacuum hoses to upper and lower intake manifolds.
14. Fuel lines and bracket at the rear of the lower intake manifold.
15. Throttle linkage and bracket.
16. Wiring harness connectors and brackets.
17. Air cleaner intake duct.
18. Fill and recheck the coolant level.
19. Negative battery cable.
20. Inspect for leaks:
a. Turn the ignition switch to the "ON" position for 2 seconds.
B. Turn the ignition switch to the "OFF" for 10 seconds.
C. Turn the ignition switch to the "ON" position.
D. Check for fuel leaks.

_________________________

Hope this helps.

Take care,
Joe