ABS/brakes not working properly

2004 MAZDA 6

215,000 MILES • 3.0L • 6 CYL • 2WD • AUTOMATIC

ANGEL LONG

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I'll start at the beginning. I bought this car as a fixer-up. When I got her she was on 2 flats, green from sitting 2 years, and the master cylinder was broken. When I say broken, I mean the lid was tore off of the reservoir and the brake fluid was close to empty. So I order a master cylinder, get my buddy to install it, and about 2 weeks later we're on the road. I'll skip the details not pertaining to the current issue (read: fuel/emission pains) and jump to where I stand now. My friend put on front brakes and since then the pedal has been spongy. First tap goes to the floor and then slowly gets more stiff after. We've bled the system 3 times now and still no improvement. I searched the internet and lo and behold I find a post similar to my problem. In said post someone mentions that the ABS module could have gotten air in it and the only way to bleed it out is to have a mechanic do it with their scanner or borrow/buy one from the parts store. Well, I called a local garage and they tell me they don't have the tool to do it. I go to the parts store and they act as if they've never heard tale of such a thing, but they'll try it if I bring the car over. I guess at this point what I'm looking for is any alternative opinions and, or, options to bleeding air from the ABS module.

All inputs appreciated and welcome!

Dec 9, 2020 at 4:01 AM

JACOBANDNICKOLAS

CERTIFIED EXPERT
110,175 POSTS

Hi,

If I understand correctly, the brakes worked when the new MC was installed, and the problem started when the front brakes were replaced.

I have to ask, was the system opened? To replace pads, it shouldn't have needed to be opened. Next, what it sounds like you are referring to is called an automated bleed procedure. The vehicle doesn't have that ability. Here are the bleed directions right from the manual.

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2004 Mazda 6 V6-3.0L DOHC
Procedures
Vehicle Brakes and Traction Control Hydraulic System Brake Bleeding Service and Repair Procedures
PROCEDURES
AIR BLEEDING

Caution: Maintain the fluid level in the reservoir tank proper while bleeding the air.

Specified fluid SAE J1703, FMVSS 116 DOT3

Note: The brakes should be bled whenever a brake line is disconnected. If a hydraulic line is disconnected at the master cylinder, start at the slave cylinder farthest from the brake master cylinder, and move to the next farthest slave cylinder until all four cylinders have been bled. If the disconnection point is anywhere except the master cylinder, start at the point closest to the disconnection, and move to the next closest slave cylinder until all four cylinders have been bled.

1. Remove the bleeder cap and attach a vinyl tube to the bleeder screw.
2. Place the other end of the vinyl tube in a clear, fluid-filled container.
3. One person should depress the brake pedal a few times, and then hold it in the depressed position.

pic 1

4. A second person should loosen the bleeder screw, drain out the fluid and close the screw using the SST.
Tightening torque
Front: 6.9 - 9.8 Nm (71 - 99 kgf-cm, 62 - 86 inch lbs.)
Rear: 5.9 - 8.8 Nm (61 - 89 kgf-cm, 53 - 77 inch lbs.)
5. Repeat steps 3 and 4 until no air bubbles are seen.
6. Bleed air from each component by following the procedure above.
7. After air bleeding, check the following:
^ Brake operation
^ Fluid leakage
^ Fluid level

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Let me know if this is what was done. Also, you could pressure bleed this system. That is the only other option I know of. One last question. Check the rubber brake hoses in the front and make sure one of them isn't expanding when you press the brakes. You will need a helper for doing that.

I will watch for your reply.

Joe

Image (Click to enlarge)

Dec 9, 2020 at 7:27 PM