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Possible master cylinder symptoms

Toyota Corolla 2015, 58,000 miles. Well maintained.

Symptoms are, after sitting overnight the brake pedal is a little low and hard, as if the brakes were pumped after the engine was turned off. Once the engine is on the pedal comes up and brakes are normal. Even sitting several hours during the day the ‘feeling’ is normal.

Does this sound like a leaking master cylinder? Any other ideas.

Not a job I want to tackle myself but want to be prepared when I talk to my local shop. Of course will start with symptoms and not just ask for a mc replacement. But my shop is smart enough to get the back story before working on a job.

Not suppose to do that. I guess there could be a little bit of air in the system causing that.What about maintenance: did you ever get a part of the brake system replaced before this happened? caliper,hoses etc?maintenance schedule for this car involved replacing the brake fluid at set intervall.What color is the fluid?

No … it sounds perfectly normal. What you are experiencing is what a power brake vehicle brake pedal feels like when it is unassisted by the vacuum of the engine and Power Brake booster. Perfectly normal.

However this begs the question of… Why are you trying to use or feel the brake pedal before you start the vehicle?

Its like the old scenario of… Doctor…it hurts when I do this… Then don’t do that… LOL… sorry

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Concur w HB above, there is probably no problem at all. If there is a problem , given the engine running vs not running aspect I’d suspect it was w/ the brake booster more than the MC.

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The brake booster is not holding vacuum, it should hold vacuum over night.

If this Corolla has the optional proximity key system the brake must be applied to start the eng

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Dernit… there goes @Nevada_545 making all kinds of sense again… Yes, I will have to concur… that is correct that the booster should hold vac…and provide one maybe two pushes of the brake that would seem assisted.

That sorta flew right over my head. Silly me… I concur with Mr Nevada. Now I have to go out and push my brake pedal cause Im that kinda guy. My vehicle doesn’t require this upon startup…regardless…I believe Nevada is still correct. There should be one or two pedal pushes before that remnant vacume is gone.

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I do have to have the brake pedal pressed to start the ignition. This afternoon I am going to pull all the wheels and look at everything in detail. Than ks much for the info.