mahanddeem

Hello,
I'm having an issue of hard to depress brake pedal when starting the car in the morning (or when car sits for several hours). Few times made starting car difficult since it needs to be depressed a bit for the ignition to fire (and not go to ACC or ON). After some force it moves a bit. Then rest of the day it behaves normally.
Brake fluid level is normal in the reservoir. No obvious leak anywhere. Never touched the brakes (pads or rotors) since I got the car 8k miles ago, now at 88k miles in my 09.

MadMax07SL

Brake booster isn't holding the vacuum is my guess. Could be a bad booster, could be a loose or leaking hose...

LtLeary

I thinking master cylinder. Probably scored or grooved (although I have seen rust before.) Will most likely continue to get worse and eventually affect braking.

VeeQue35DE

Probably master cylinder.

MadMax07SL

You guys aren't listening to the symptom. It's after a spell, pedal is hard. Like if you were to have the car off and pump the brake pedal. It gets stiffer after a few pumps, or after the booster has lost the residual vacuum. He didn't say they stay that way once the car starts.

To the OP, that's not to say you don't need to get them serviced. 88k miles, those pads should be replaced regardless of the remaining meat on them, rotors turned or replaced. Only replace if warped. That many years old, I'd also suggest that the brake fluid be flushed out and replaced. All that said, I still think that the symptom you are describing sounds like the brake booster is letting go of the vacuum over a few hours.

mahanddeem

Thanks MadMax,
You are right, I would suspect master cylinder if symptoms persist with irregular braking problems, sinking pedal or weakness. Brake is behaving normally once car starts and pedal travel and power is normal(until car sits for 8+ hours). Rotors and pads seem good to inspection. But I will double check too.
I think I will go ahead now with a brake fluid flush and see if that helps. Per the car records, previous owner had that done at a Nissan dealer like 2 and a half years ago.

Tarzan

It is a booster vacuum leak, or valve stuck open, or a hose cracked.
Start with inspecting the hoses and one-way valve. They are cheap and easy to replace.
If it does not help, then move on to replacing the booster.

User1

^ This is why you are having this problem. Some dealership grease monkey has had his greasy *** hands under the hood. Check everything at this point, starting with the easiest/most obvious as stated above. And obtain specific records from that dealership if you can. The answer is always in the history.

mahanddeem

Thanks all for suggestions.
Update!
Weird solution that worked so far! Yesterday I took the car to the car wash, popped the hood and waited for few minutes, sprayed 3M engine degreaser, let it sit for 5 minutes and washed the engine bay with low pressure water. I emphasized the wash around the brake master cylinder area and below that. Car feels lighter now and seems to run cooler though it never overheated before.
But the surprising thing is that this morning the brake pedal wasn't hard, and back to normal. Not sure if it's a confirmed solution. Will keep an eye on it. Fluid level normal.
If it turns out to be fixed, I'd blame it to the complex dumb blower workers who just blows the sh** into residents cars. Must have been some dirt, particles, grass got somewhere in the brake system somehow.

MadMax07SL