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Discussion Starter · #1 ·
So I recently changed the front pads and rotors and have some issues with a soft brake pedal after the job was done.
It is a 2014 turbo without electric parking brake.

To this point I have bleed the brakes both by pumping the peddle and vaccume bleeder which I probably will never do again. I didn’t like that process at all and have no faith in it now.

I bought a Autel mx808 which can bleed the brake booster thinking it had air trapped maybe and have done that 3 times now with no help either.

I have bleed both front and rear brakes at this point multiple times so I figured I must have blew a seal out of the master cylinder pushing the pads back in because I forgot to open the cap to the master cylinder. I replaced the master cylinder with a factory mondo one and still have soft pedal.
I’m running out of ideas and need some help on this one as to what else may be messed up.

I did notice a puddle of fluid on the floor after pushing the caliper pistons back in but it’s been almost 3 weeks now and I don’t remember if I even noticed where the fluid pushed from. I assume it pushed past the seal on the master cylinder tank as I do remember it being completely full when I opened it.

the brakes do still work and will even lock up both front and rear tires, abs works etc.

Pedal can be pumped a couple times with the car running and get hard but then bleeds down to nearly the floor within a few seconds

Thanks for any help you can provide I’m stumped and don’t want to replace more parts without knowing how to tell what is wrong.
FYI I haven’t been losing fluid in the 2 weeks I have been driving it so I don’t think I have a leak from a caliper etc.
 

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2011 Kia Optima
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One needs to careful when bleeding using the brake pedal, so a board or something thick should be placed under the pedal to stop it from going to the
floor as it could jam the mc piston. A stuck mc piston can be seen when it is removed as the piston doesn't return all the way. When I replaced all
the calipers on the '11, although never having a problem with the vacuum bleeder, this time couldn't get a hard pedal, so I had the wife pump the pedal
and when done, finally a hard pedal.

I'd bleed them again.
 

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Discussion Starter · #3 ·
I’m bleeding them with everything put back together, new pads and rotors in etc, so no issues over extending the caliper pistons. As for the MC piston it’s a new master cylinder so I’m not concerned with rust or trash in the unused part of the bore causeing piston seal issues from overextending. The old MC appears to be fine also after I replaced it so I don’t think that I over extended even the old one.
I guess I’ll try and bleed them again. I have bleed them to the point all new fluid is coming out of every caliper but i think I’ll go ahead and use up the rest of the quart of fluid I have and keep bleeding.
Thanks
 
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