Brake Pedal After Stop

[coolwater]

I have the same problem with my Honda and now my ES as well. And, it only happens during the summer--only when I use the A/C. After car stops, the brake pedal sinks even deeper and all the way to the floor. My friend says he has the same problem with his Acura and he says the problem is with the master cylinder. But, my question is... why it only happens when the A/C is used?

Okay, then, how much would it cost me to replace the master cylinder? Can I have it done at Toyota dealer instead of Lexus and save some money? Or, can I just use any auto repair shop? I still have 3-month warranty with the Suzuki dealer where I bought my ES. Can I take it back to them and trust that they will do the proper job on my car? (My ES has traction control and I wonder if the Suzuki dealer knows the difference.... <_< )

[mbpgawest]

Hey coolwater, sounds like a classic leaking master cylinder. I don't think that it would be a big deal to take it back to the dealer where you bought it form. Changing a master cylinder is not that difficult.

[kyle0k]

wait a second i think this does it for me too,but i tihnk only at the bigiing liek at one stop after a cold start. and is this master cylinder must be replaced or is it something just u replace for comfort of knowing its not cracked

[coolwater]

But, what's the thing with the a/c? The master cylinder tends to leak only when the a/c is on? Is that the case? As for my Honda (also for my friend's Acura), the 'brake pedal sink' only occurs during the summer--when the a/c is used.

Second, it seems that there are two kinds of master cylinders for ES--one for ES with traction control and the other for ES with no traction control. This is why I'm not sure about taking my car back to the Suzuki dealer.

Does anyone know how much it would cost at Toyota dealer? The part alone costs around $150 online.

[SKperformance]

call to gauge prices , it is your local area so only you know who you would go to ,so get their prices .

Also if it softens when the a./c is on at a stop it isn;t crazy as a problem as the a/c kicks inthe throttle is closed but the rpms raise to compensate for the drag on the engine. So you will end up with more vacume causing the pedal to sink slightly.

Check the idle control valve also as it can cause idle vacume problems also if diagnoised properly.