Spongy brakes 2010 CX9 GT

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2010 Mazda CX-9 Grand Touring
Hi last year my brakes became hard to press when braking so I changed the brake booster and it went back to normal. Now my brakes feel spongy, I can't hold a sudden brakes. Changed the master cylinder and problem still exist, changed the brake booster again and it is still spongy. I am lost anyone has any advice?
 
Two things come to mind and forgive me if you have already been over these items. First, has the entire system been bled properly, preferably with a pressure bleeder. Second, have you inspected the brake lines, particularly the rubber lines at the wheels. If those parts get weak they can 'baloon' under pressure and give a spongy feel to the brakes.
 
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2010 Mazda CX-9 Grand Touring
I will relay these questions to the mechanic. I know that he bleed the brakes when he changed the master cylinder. Thanks for the suggestions.
 
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Mazda CX-9 Grand Touring 2016
If the brake hoses are weak and ballooning, that's dangerous. I like OEM quality "rubber" brake hoses, actually EPDM liner, fiber reinforcement, probably EPDM outer cover. I've had a stainless brake hose fail...the teflon liner is not the best for flexing, and that's what failed. If it had been an EPDM inner tube, that would have been fine.

Some vehicles are tricky to fully bleed all the air out. The air bubbles will rise, naturally, and one needs to find any high spot in the system and bleed there. Some mechanics bleed only at the wheels and miss the high spots.
 
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2010 Mazda CX-9 Grand Touring
Thanks for this info, I spoke with the mechanic he will recheck the hoses and bleed it again. I always use OEM parts. I changed the rotors to slotted and cross drilled initially when I bought the CX9 because the braking was not sharp on the OEMs.
 
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2010 Mazda CX-9 Grand Touring
Sorry about the late update, but the problem was the front right caliper. One of the valves had a leak I replaced both front calipers. Eventually the TCS light and brake light came on.
 

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