Brake pedal slowly goes to the floor

Tiny
JOSHWEEDEMAN
  • MEMBER
  • 2005 CHRYSLER TOWN AND COUNTRY
  • 3.8L
  • 6 CYL
  • 2WD
  • 90,000 MILES
And drivers front caliper will not fully release. Front end shutters as well when braking at high speed. I have exhausted any ways of fixing just got back from mechanic and he cannot figure it out. Van has brand new calipers rotors and master cylinder, new brake flex lines and new rotors and pads in the rear as well. All front end components are solid with no play including wheel bearings. No leaks either.
Thursday, July 25th, 2019 AT 8:52 PM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

Did your guy do the automated brake bleeding of the ABS system with a scan tool?

That is mandatory to get rid of the air in the ABS module.

Roy

STANDARD PROCEDURE - ANTILOCK BRAKE SYSTEM BLEEDING
The base brake's hydraulic system must be bled anytime air enters the hydraulic system. The ABS though, particularly the ICU (HCU), should only need to be bled when the HCU is replaced or removed from the vehicle. The ABS must always be bled anytime it is suspected that the HCU has ingested air. Under most circumstances that require the bleeding of the brakes hydraulic system, only the base brake hydraulic system needs to be bled.

When bleeding the ABS system, the following bleeding sequence must be followed to insure complete and adequate bleeding.
1. Make sure all hydraulic fluid lines are installed and properly torqued.
2. Connect the scan tool to the Data Link Connector. The connector is located under the lower steering column cover to the left of the steering column.
3. Using the scan tool, check to make sure the CAB (MK20e) or ABM (Mk25e) does not have any fault codes stored. If it does, clear them using the scan tool.

WARNING: WHEN BLEEDING THE BRAKE SYSTEM WEAR SAFETY GLASSES. A CLEAR BLEED TUBE MUST BE ATTACHED TO THE BLEEDER SCREWS AND SUBMERGED IN A CLEAR CONTAINER FILLED PART WAY WITH CLEAN BRAKE FLUID. DIRECT THE FLOW OF BRAKE FLUID AWAY FROM YOURSELF AND THE PAINTED SURFACES OF THE VEHICLE. BRAKE FLUID AT HIGH PRESSURE MAY COME OUT OF THE BLEEDER SCREWS WHEN OPENED.

4. Bleed the base brake system using the standard pressure or manual bleeding procedure.
5. Using the scan tool, select ANTILOCK BRAKES, followed by MISCELLANEOUS, then BLEED BRAKES. Follow the instructions displayed. When the scan tool displays TEST COMPLETED, disconnect the scan tool and proceed.
6. Bleed the base brake system a second time. Check brake fluid level in the reservoir periodically to prevent emptying, causing air to enter the hydraulic system.
7. Fill the master cylinder reservoir to the full level.
8. Test drive the vehicle to be sure the brakes are operating correctly and that the brake pedal does not feel spongy.
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Monday, March 15th, 2021 AT 12:41 PM
Tiny
JOSHWEEDEMAN
  • MEMBER
  • 3 POSTS
Thank you for your quick response. I'm going to see if the other shop we have in town is capable of this. This started happening when we were on a trip before anything was opened up, could it be possible to get air in the abs from boiling brake fluid if a caliper got hot from slight drag or such?
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Monday, March 15th, 2021 AT 12:41 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Yes It could. Good observation.

Roy
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Monday, March 15th, 2021 AT 12:41 PM
Tiny
JOSHWEEDEMAN
  • MEMBER
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Thank you sir.
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Monday, March 15th, 2021 AT 12:41 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You are welcome.

Always glad to help.

Roy
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Monday, March 15th, 2021 AT 12:41 PM

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