Brake Pedal Problem

[Davicho]

About 4 months ago I was on my daily commute when I had to brake hard to avoid a collision. ABS was activated and pedal went to floor but my MZ5 did manage to continue to stop. After incident pedal stood spongy and would have little to no resistance and would sink near the floor before actually firming up and braking. I had the brake lines professionally bled at my work (non-Mazda dealer) and pedal feel was back to normal.

About a month later I had to brake hard again because some lady decided to stop suddenly and turn into a gas station without signaling. Again, ABS was triggered and pedal sank to the floor and remained spongy and act as previously described. This time I had our tech bleed the lines and do a brake fluid flush. Pedal went back to normal.

Another month went by and out of the blue without ABS being triggered pedal went to floor and again stayed as previously described. This time I took it to Romero Mazda and had them check it out. Of course, they checked the entire system (supposedly) and everything checked out okay. I had them bleed the lines as well as the clutch hydraulic system since they both use the same reservoir and pedal was back to normal once again.

Three days ago I went over a road imperfection as I was braking and ABS was triggered, again same scenario but this time when I would press the brake pedal i can hear a SWOOSH sound followed by a WHINE MOANING sound when released. I decided to take it to Redlands Mazda this time and described the past occurences. I just received a call from them saying that the ABS system is okay and no codes have been thrown. They suspect that the master cylinder is internally leaking as there is no sign of fluid anywhere in the entire brake system. I gave them the okay to replace it and should be ready Friday night (hopefully).

We will see if this fixes the problem once and for all. I will report back and update. Again no ABS light or CEL was ever triggered.

 

[kw_da]

Sounds dangerous. Did the dealer test activating the abs system after they fixed it? Brake hard so that its activated? If I were you, I'd test the abs on a clear road before you have to use it again in anger.

Seems like the ABS breaks the brakes.

I did some googling - found:

"Another common cause of ABS failure is corrosion in the modulator valve assembly. This is caused by a failure to change the brake fluid. As the fluid absorbs moisture to the point of saturation, the water attacks the metal components in the valve assembly, causing the valves to stick open or closed."
Read more: Anti-Lock Brake Problems | eHow.com http://www.ehow.com/about_5380054_antilock-brake-problems.html#ixzz2DdM6HcJI

It sounds like your ABS solenoid is sticking closed?

David

About 4 months ago I was on my daily commute when I had to brake hard to avoid a collision. ABS was activated and pedal went to floor but my MZ5 did manage to continue to stop. After incident pedal stood spongy and would have little to no resistance and would sink near the floor before actually firming up and braking. I had the brake lines professionally bled at my work (non-Mazda dealer) and pedal feel was back to normal.

About a month later I had to brake hard again because some lady decided to stop suddenly and turn into a gas station without signaling. Again, ABS was triggered and pedal sank to the floor and remained spongy and act as previously described. This time I had our tech bleed the lines and do a brake fluid flush. Pedal went back to normal.

Another month went by and out of the blue without ABS being triggered pedal went to floor and again stayed as previously described. This time I took it to Romero Mazda and had them check it out. Of course, they checked the entire system (supposedly) and everything checked out okay. I had them bleed the lines as well as the clutch hydraulic system since they both use the same reservoir and pedal was back to normal once again.

Three days ago I went over a road imperfection as I was braking and ABS was triggered, again same scenario but this time when I would press the brake pedal i can hear a SWOOSH sound followed by a WHINE MOANING sound when released. I decided to take it to Redlands Mazda this time and described the past occurences. I just received a call from them saying that the ABS system is okay and no codes have been thrown. They suspect that the master cylinder is internally leaking as there is no sign of fluid anywhere in the entire brake system. I gave them the okay to replace it and should be ready Friday night (hopefully).

We will see if this fixes the problem once and for all. I will report back and update. Again no ABS light or CEL was ever triggered.

 

[Davicho]

UPDATE

Got my MZ5 back last night after getting the master cylinder replaced. I test drove the crap out of it before paying and leaving Redlands Mazda. I triggered the ABS pump about 5-6 times going slow and about 30mph and....it's perfect!!! ABS acts as it should and pedal does what it suppose to while ABS is on and after. Very well done Redlands Mazda!! Goes to proof that there is everything out there...good, bad, competent and incompetent techs and dealerships.