JD-MAX

I've noticed for the last week or so every time I get in my car in the morning and push on the break to start the car, it's very hard. Has anyone experienced this? The car starts and operates normally otherwise....

Tommy6905

That usually goes in line with a dead battery, what year do u have?

Akiyukio

iTrader: (1)

ARGH

I doubt having difficulty pushing the brake pedal would mean that the battery is near dead.

I believe there may be a leak in the brake booster system causing the vacuum to be slowly lost after the engine is shut off.

Try it a few times: With the engine off, depress and release the brake pedal a few times and feel it slowly get harder to push as the vacuum is used up. (Usually happens after 2-3 presses of the brake pedal.)
Once you've used up the vacuum, you'll learn what is the force needed to push the brakes in an engine cutoff emergency.

At any rate though, I have no idea how to check for brake booster/vacuum leaks.

JD-MAX

When you get in your car and go to start it for the first time that day, see if you notice if it is hard or more like when the engine is running. Maybe it's always been hard and I didn't realize it? If not, Akiyukio's explanation makes sense.

Tommy6905

Maybe your right, I'm just speaking from personal experience, my battery was coming to it's end of life, and I remember a few times before it was completely toast that the brake would be hard when starting. I changed the battery and haven't looked back

Akiyukio

iTrader: (1)

Hmm, different experiences I guess.

I'll go test it out and see if there is a difference. I have a lead foot, so maybe that's the reason I didn't notice .

JD-MAX

Cool let me know!

Akiyukio

iTrader: (1)

My brakes feel about the same with the engine off and with the engine on.
Perhaps slightly softer with the engine on since the engine is providing a vacuum and all.

If your car is still under warranty, I suggest taking it in and seeing what the dealer says.

JD-MAX

Hmm, there must be a problem then. It's definitely a night and difference from when the car is on vs off. I'm out of warranty, maybe next time it's in I'll ask them to check it out.

Thanks for checking yours for me bro.

Lanzz

I had this issue - was a defective vacuum booster. Don't wait to get it fixed, it can cause brake fluid to be injested into the intake and cause other issues. I ended up with a check engine light, a low brake fluid reservior and a ruined mass air flow sensor from the brake fluid.

JD-MAX

Thanks for the heads up! I realized today this definitely cant be normal. Was it expensive to fix just the defective vacuum booster and did you have the dealer fix it or do it yourself?

JD-MAX

I know I sound crazy here but I think it may be fine after all. I tried this and want to see if any of you feel the same thing.
I got in the car pushed on the pedal before starting and it's firm/hard, start the car and it becomes normal. Turn the car off and pump the brakes about 3 times and it's back to firm/hard. Maybe I'm nuts and there isn't a problem???

xtreme1

I have the same thing happening to my car 2009 and i wasn't sure if that was normal. I thought that maybe i accidentally stepped on the brake pedal while the car was off and i thought i wasnt supposed to. Should i take it back to where i bought it from to check on that since ive only had it for about a month ?

Akiyukio

iTrader: (1)

I could have sworn I mentioned this in my post above...(#3 of this thread)
The brakes requiring more force to push after 3 pumps with the car just turned off is normal.
The brakes not touched overnight and requiring more force to push upon next start up is not.
Heck, even if I leave my car turned off for a week, the brakes will still remain soft when I go to start it. What you most likely have is a leaking brake booster.

You can step on the brakes all you want with the car on or off.
How else would you stop a car that suddenly lost power on the highway?
On the other hand, if you are having the same symptoms as JD-MAX, reread this thread, and take it in.

xtreme1

Yeah but I mean everything else works fine like it starts with no problems so since it doesnt affect anything they are probably just gonna say that it's fine. But yeah like i have to step on it a lot harder with the car off than when the car is on..the first time that happened the car didn't even start at first because i didnt push it hard enough

CorollaULEV

This is NOT NORMAL!!! PERIOD!!

End of story!

Look up the function of a brake booster. Not gonna explain it aside from saying that it uses (AND STORES) engine vacuum to assist with brake force.

If the brake pedal feels normal while driving and becomes hard to press after engine has been shut off, this is ABNORMAL. It means there is a vacuum leak somewhere (most likely internally in the brake booster - that be the big round circular thingy that the brake fluid reservoir is attached to).

Go get it fixed....

Late,
Trav

Lanzz

I agree, it's not normal. I do not know how much it cost, as my car was under warranty at the time. The dealer replaced the brake booster, MAF sensor and a bunch of assorted odds and ends. Also - they had to bleed the brakes after the replacement.

xtreme1

Ok I called the dealership today and they said they would have to look at it so I made an appointment for tuesday. I'll let you guys know what they say

PSU09MAXIMA

I also wonder if you bought your car as Certified Pre Owned then this would even be covered under that as well. If anyone knows either way let me know.

xtreme1

Ok I just got back from the nissan dealership and they said that there's nothing wrong with it. They said the break booster only works when the car is on and they said it's not supposed to store vacuum when the car is off and that it will leak over time.

CorollaULEV

Don't care what they told you....that is not true. If it leaks then it leaks.....and it should NOT leak...at all ever. Mine can sit for a week and the brake pedal feels exactly the same as when I parked it. This is abnormal.

I will look up the guidelines from the Nissan factory service manual and post up. Telling you now, dude....they are not being honest with you or they just don't know. Neither situation is good.

Late,
Trav

CorollaULEV

It doesn't work with engine off, but it DOES store vacuum....that's part of the functionality of brake boosters. Look it up on Google....educate yourself....don't take my word for it. This is some thing needing fixed.

xtreme1

I know but I mean they are obviously not gonna listen to me because they are the mechanics.. I tried to explain to them but they wouldn't listen to anything that I had to say.. So obviously if they are saying that there's nothing wrong with it then they are not going to fix it so I have no choice but to deal with it.. Hopefully it gets worse before my warranty is up (which was only 2 months so i have 1 month left)so that I can get it fixed for free if not then I'm gonna have to pay for it... But yeah he even let me go into a different car to try it and i told him that the other one was not hard and he was like yeah but that one has more miles.. like what does the mileage have to do with that? I feel like he didn't know what he was talking about which pisses me off.

Nopike

iTrader: (2)

Take it to another dealer.

RCM78

Theres nothing wrong with your car. EVERY car with power brakes will have a firmer pedal when the car is off. As soon as you start the car the pedal will feel normal.

CorollaULEV

ABSOLUTELY POSITIVELY NOT TRUE! If the brake pedal is normal and nice and squishy with engine running but firm after engine is turned off and allowed to sit for a while, this is a tell-tale sign that the brake booster is LEAKING. Do some research. It STORES VACUUM!

Turn engine off and THEN pump brakes 4 or 5 times....yeah....pedal gets firm and stays firm. That's normal....because you are using up the STORES VACUUM. But if you turn car off, get out and leave it for a day and THEN come back to a firm pedal....you gots problems.

Do some research on this.

RCM78

I don't have to do any research. I understand completely how power brakes work. You do not!!!

It is perfectly normal for the brake pedal to feel FIRMER when the engine isn't running. As soon as the engine starts the pedal will soften and feel normal. ALL cars with power brakes behave this way.

You can disagree with this all you want. It doesn't change how the brakes work and it certainly doesn't make you appear to know what your talking about...

Johnnyru

+1

CorollaULEV

You, friend, are right in a sense. With engine RUNNING, there is vacuum in the manifold. Vacuum in the manifold is shared with the brake booster (hence, vacuum-assist brakes, or power brakes).

Once you shut the engine off, there is no more vacuum in the manifold. Ok - fine. Engine vacuum is gone.

There SHOULD be vacuum in the brake booster, though. The brake booster STORES engine vacuum (a limited amount).

Heck - read the owner's manual. It clearly states that if you loose engine power, you will have enough vacuum assist to hit the brakes a FEW times, and THEN the brake pedal will become much harder to press.

Try it - seriously. Get in your car right now, start the engine and press the brake pedal. Then shut it off and press the brake pedal again. It will NOT feel any different....until you pump the brakes 3 or 4 times. After that, it will feel very firm.

I agree - engine off, the pedal is firm, but IF and only IF you have pumped the pedal a few times. If you have literally shut the engine off 2 seconds ago and the brake pedal goes firm as SOON as you shut the engine off, you have a serious effin problem (large vacuum or master cylinder fluid leak).

As said, don't take my word for it, try it for yourself. Shut the engine off and pump the brake pedal a few times. It will feel normal on the first and second pump and will gradually get firmer after 3 or 4 pumps - that's because you are using up the STORED VACUUM.

When the pedal becomes firm with engine off and without pressing brake pedal...if it isn't the brake booster LEAKING AIR INTO the booster, then it is the MASTER CYLINDER LEAKING FLUID into the booster.

BTW - are you seriously saying that it's normal to have a soft pedal with engine running and a firm pedal when engine is off if you have NOT pressed the brake pedal at all once the engine is turned off??

You crazy if you say yes...

And if you leave a car off and the brake pedal becomes firm after ANY length of time, it means you have an AIR or BRAKE FLUID leak into the brake booster.

Say what you want, dude - if this is what your car does, then you deserve it.

RCM78

OK, so lets get specific here.
Yes the booster will work for a short amount of time after the engine is off.

I think you're mistaken about the booster storing vacuum though. Unless theres a hard valve in the vacuum line the booster will always leak back through the engine valve train. It takes some time but it will happen.

If the booster is in fact leaking the engine will run rough and probably throw a code.

So, The original poster simply asked if a firm pedal before starting the car was normal. It is...

The only exception is if you press on the brakes right after turning the engine off. But who does that?

Nopike

iTrader: (2)

FWIW my 2104 has been sitting all night I went and pressed the brake pedal to check if it is "stiff" or not. I would say it is stiff, it certainly does not provide the assist you get when the car is running. I don't think there is anything wrong with my brake booster. So to the OP I would say there is a good chance that your car is fine.

CorollaULEV

I just don't think that's normal. Maybe they designed the new ones to leak.

My 2010 is not like that. Even after sitting for over a week, pedal feels as soft as it does when running.

BIGIRISHSTL

^^^ maybe there is something wrong with yours!!!

JD-MAX

Thanks guys for all the input! I called the dealer shortly after I made this post and it sounds like a $500 some dollar job. 300 for the booster and 200 for labor +/-. I looked up aftermarket boosters and they are way cheaper, like $100. Anyway, they said this is not a common problem that they have heard of but I could bring it in and they can check it out. I decided to hold off for now.

I don't remember having to push so hard on the pedal just to start the car. Like Xteme1, I've had it where I had to push the start button again and push a little harder on the brake pedal to get the car to start. So I have to say that CorollaULEV theory makes sense. Anyway, I'll leave it and hope for the best for now. If anyone else ends up getting theirs fixed keep us posted!