Hi,
If there is air still in the system, that can cause it. Here are the directions for bleeding right from Alldata. Take a look through them and let me know if this is the procedure you followed.
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1997 Chevy Truck S10/T10 Blazer 4WD V6-4.3L VIN W
Manual Bleeding
Vehicle Brakes and Traction Control Hydraulic System Brake Bleeding Service and Repair Procedures System Bleeding Manual Bleeding
MANUAL BLEEDING
NOTE: Bleeding is necessary if air has entered the hydraulic brake system.
It may be necessary to bleed the system at all four wheels if a low fluid level allowed air to enter the system, or the brake pipes have been disconnected at the master cylinder or combination valve. If a pipe is disconnected at one wheel, then only bleed that wheel.
The time required to bleed the hydraulic system when the master cylinder is removed can be reduced by bleeding the master cylinder before installing it on the vehicle. If the brake pressure modulator valve (BPMV) has been replaced or has air trapped in it, refer to Antilock Brake System.
NOTE: 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 reseal and wipe off brake fluid containers to prevent spills.
Tool Required:
J 28434 Wheel Cylinder Bleeder Wrench
NOTE: Relieve the vacuum reserve by applying the brakes several times with the ignition "OFF."
1. Fill the master cylinder reservoirs with Delco Supreme No. 11 Hydraulic Brake Fluid GM G/M 1052535 or an equivalent DOT 3 motor vehicle brake fluid.
Maintain the fluid level during bleeding.
2. If the master cylinder is suspected to have air in the bore, bleed it before any wheel cylinder or caliper.
A. Disconnect the forward brake pipe connection at the master cylinder.
B. Allow the brake fluid to flow from the connector port.
C. Connect the brake pipe but do not tighten.
D. Slowly apply the brake pedal and allow the air to bleed from the loose fitting.
E. Tighten the fitting before releasing the pedal.
F. Wait 15 seconds.
G. Repeat this sequence, including the 15 second wait, until all air is purged from the bore.
H. After all air has been removed from the forward connection, repeat this procedure for the rear pipe.
3. If the BPMV is replaced or suspected to have air trapped inside, it must be bled next. Refer AntiLock Brake System.
4. Bleed each wheel in the following sequence:
A. Right rear
B. Left rear
C. Right front
D. Left front
5. Attach J 28434 to the wheel cylinder/caliper bleeder valve.
Immerse the opposite end of the hose into a container partially filled with clean brake fluid.
6. Slowly apply the brake pedal one time and hold.
7. Loosen the bleeder valve to purge the air from the wheel cylinder/caliper.
8. Tighten the bleeder valve and slowly release the pedal.
9. Wait 15 seconds.
10. Repeat this sequence, including the 15 second wait, until all air is purged from the wheel cylinder/caliper.
11. Tighten the bleeder valve to 7 Nm (62 inch lbs.).
12. Continue Steps 5 through 11 at each wheel until the system is bled.
13. Check the brake pedal for "sponginess" and the brake warning lamp for an indication of unbalanced pressure. Repeat the bleeding procedure to correct either of these conditions.
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Here is a link that discusses possible causes of a brake pedal going to the floor:
https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor
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Let me know. Also, let me know if you bench bleed the new master cylinder.
Take care,
Joe
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Friday, March 19th, 2021 AT 11:57 AM
