I recently had to slam on my breaks at an intersection and immediately afterwards my break pedal started sinking (system loosing pressure). I looked around insides engine compartment and around the wheels but do not see any leaking fluid. I topped off my break fluid reservoir just to make sure. I am not sure if it’s the MC or the ABS module. Any ideas on where I should start

 

Probably blew a seal in the MC. Not many 2006s have ABS, are you sure yours has it?

Have the rear drums ever been adjusted? Have you inspected front and rear pads/shoes?

 

I don’t know if it has an ABS module. Guy at Autozone said there is an ABS cyl back by the rear wheels. Anyways if there is no ABS up front then I can rule it out...and just focus on the MC.

thanks for lighting speed response...really cool!

 

Don't listen to that AZ guy anymore. There is 1 ABS module it lives under the hood . Look for "JM4" on the label on the glove box door.

 

At this age, the fluid itself might just need to be flushed. As it ages, brake fluid picks up (not sure if absorb or adsorb is the correct term) water from the environmental air. The water is more compressible than brake fluid, so the pedal can get soft by that alone. If it gets hot, water boils at temps well below brake system max temps, which can make it softer. It becomes much more of a problem in competitive situations, (which can be several hundred degrees, with brake rotors even glowing red).

So if there are no leaks and the master cylinder seems OK, a fluid change or flush might be in order. It's a possible DIY job, based on your comfort level, but most shops can definitely do it. No dealer needed.

 

Thanks for the input. The pedal sinks even at startup when car is still cold. Since it started immediately after slamming on my breaks I believe it’s related to a blown seal in MC (ie. nternal leak in MC). Once I replace then I’ll know for sure.

 

Can't bite my tongue any longer on this...........

It's spelled "brakes".........B*R*A*K*E*S

 

If the rear brakes have never been adjusted (common) there is a good chance that one of them blew out

 

Bought mc online from Rockauto for about $75 and had it replaced by my mechanic. However the pedal still sinks but not quite as severe as before. Still not stopping as it used too. I don’t see brake fluid leaking out anywhere. Any ideas.

 

there is another way, it is easier ...
open the hood and look into the left front corner - you should see a metal "cube" with 4 tubes sticking out of it (+ another aside). This is ABS block. You see it - it means it is available, you do not see it - not look further, it is not there.