master cylinder has been replaced? ok.. highly unlikely it will fail this quickly... and you said it was bled before you bought it. that's an indication there's a leak in the system.

Air is getting in... and in a hydrolic system.. air compresses.. brake fluid does not.. that is why your pedal is going down.. you have Air in the system

now you have to find out why.

return to the basics....Always start at the begining

1. check your brake linings..

2. does it have rear shoes or pads? wheel cylinders can leak, and cause air in system easier than calipers.

3. check brake lines for wear, chaffing, cracks.. ect

4. bleed the brakes... does it get better now?

Return with your findings and we will continune

Brian B

 

I would try bleeding the brakes first. It's cheap and relatively easy if you have a helper. Have the brakes been like this since you bought the car? If so, I would wonder if whomever changed the master cylinder didn't bench bleed the MC or properly bleed the brakes after they installed it...

 

Ok. Will try a flush and inspection and post back. The dealer is trying to say the part isnt under warranty since I didn't purchase it, but no where in the warranty booklet from ahm does it say I have to have purchased it.

 

Take your time bleeding the brakes. Make sure there are NO air bubbles at all coming out of the bleeder before moving to the next one. Be sure to constantly check the fluid in the MC while doing this because you'll have to start over if it gets dry and air gets in the system.
Good luck and let us know what happens

 

One point I totally forgot becuase they ahve rear drums.. The rear brakes have to be adujusted correctly... or the pedal will be low

Brian B

 

Since the OP's Accord is an EX trim level, it should have disc brakes on all wheels. So, the discussion regarding drums is moot for the OP, although it may help someone else in the future.

 

Yes they are all disc. I just talked to the dealer and the problem is the ABS modulator. They said it is sucking air in slowly. They want 2 grand for it. How hard is it to replace? Can I do it on my own or is it difficult?

 

I would get a second opinion. I DO NOT believe that. Is the ABS light even on?

 

No it isn't on. My friend is the new car manager and when he originally took it in they were going to fix the abs mod cause it wasn't functioning properly (I suspect the peddle was spongy) but they didn't. They bled the brakes so I think that since that temporarily fixed it that they said it was OK. If it isn't the MC or the abs mod what else could cause those symptoms? Could the o-ring on the abs mod be bad and causing the slow leak?