Starting Issue

joliett

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There is nothing wrong.
I'd love to hear your reason for how it could possibly be a fault in the master cylinder. There's nothing wrong with your Jeep.
I'd love you to tell my wife or son there was nothing wrong with the Jeep when it wouldn't start.
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mwilk012

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I'd love you to tell my wife or son there was nothing wrong with the Jeep when it wouldn't start.
1. Press the brake, 2. then press start.
If you don't do #1, you can't do #2.

You sat in the jeep with the vehicle off and put your foot on the brake pedal, thus letting all vacuum out of the booster. You then were surprised at the lack of vacuum assist.

There is nothing wrong with the Jeep other than your expectations. Next time, try remote start.
 
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So....this issue that started as an isolated incident is now occurring sporadically at least once every two weeks. Again...I attempt to depress the brake pedal when starting the Jeep, and it is extremely stiff, doesn't move, and requires much more force than normal to enable the starting system.

While I'd like to take the Jeep to the dealer, I know they won't be able to replicate the problem for awhile, and will probably need to keep it for several weeks, perhaps with no solution and/or no parts due to ongoing supply chain delays. I think I'll probably just wait until the problem manifests itself on a more frequent basis, BUT I'm a little concerned that repeatedly applying more pressure than normal on the brake pedal might create a bigger problem, become a safety issue, or eventually result in an inability to start the Jeep altogether. The Jeep brakes smoothly after being started and I haven't noticed any ill side effects thus far, but just curious if I might be creating a bigger problem by continuing to override the stiff brake pedal again and again. Appreciate your thoughts and advice...
 
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flyer92

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Press the brake harder. That’s the diagnosis.
Appreciate your reply, but that's what I am already doing and isn't really what I was asking in my last post. To clarify, I'm just concerned that repeatedly overriding the stiff brake pedal might put additional strain on other components over time and cause more problems.

I've owned several cars with the same/similar ignition system, and have never experienced this issue. However, this seems to be fairly common with the JL for some reason, and just wanted to see what others are doing about it, if anything. Many thanks.
 

mwilk012

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Vacuum in the brake booster is bleeding off while parked. You can remote start it if you think that it's going to hurt something, but it isn't. You'll never get the vacuum system to be 100% sealed, but if it is happening so consistently that it is annoying, replace the check valve going into the brake booster from the vacuum pump. It's easy and you'll feel like you did something.

Other than that, just don't touch the brake pedal when the Jeep is off until you want to start it.
 
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flyer92

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Vacuum in the brake booster is bleeding off while parked. You can remote start it if you think that it's going to hurt something, but it isn't. You'll never get the vacuum system to be 100% sealed, but if it is happening so consistently that it is annoying, replace the check valve going into the brake booster from the vacuum pump. It's easy and you'll feel like you did something.

Other than that, just don't touch the brake pedal when the Jeep is off until you want to start it.
Thanks for the great feedback. I was thinking along the same lines, and will probably just continue overriding the stiff brake pedal because I don't have remote start and it seems like the same issue will eventually happen again, even after I replace the check valve. Although it's more of an annoyance than anything else, it's still odd that this is the only vehicle I've ever owned with this problem.
 

joliett

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I had to use two feet pressing the brake pedal really hard. It will work...

Remote starting will also work... I'll try it next time myself
 
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I had to use two feet pressing the brake pedal really hard. It will work...

Remote starting will also work... I'll try it next time myself
Wow...if it gets to the point that I have to use two feet, then it's definitely abnormal and time to take it in for service. When this occurred, was it a single incident, or did it happen after several instances of stiff pedal upon starting?
 

joliett

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Wow...if it gets to the point that I have to use two feet, then it's definitely abnormal and time to take it in for service. When this occurred, was it a single incident, or did it happen after several instances of stiff pedal upon starting?
It Happened about 3 or 4 times. It's nothing wrong with the Jeep. It happens on other cars too. Just remember if you get an obvious hard brake pedal, and the car won't start, it's the brake pedal.

Can happen just sitting in Park and listening to the radio, with your foot on the brake, or tapping the brake... That's perfectly OK and designed like that...
 

XYJGuy

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It Happened about 3 or 4 times. It's nothing wrong with the Jeep. It happens on other cars too. Just remember if you get an obvious hard brake pedal, and the car won't start, it's the brake pedal.

Can happen just sitting in Park and listening to the radio, with your foot on the brake, or tapping the brake... That's perfectly OK and designed like that...
I have what I think is the same issue and I have less than 700 miles. This is not acceptable and this is not normal in any way..I own several cars with push button start and none have ever had this issue. Searching the forums, this problem or similar issues have been going on since the beginning of the JL in 2018. I'll be calling jeep cares tomorrow as well as the dealer.

On a positive note, this is great info about the brake issue and this is an amazing forum with great members trying to help (thank you!). FWIW, my issue was that I drove a short distance, parked for 30 minutes, came back to the car and pressed on the brake (rock hard) and hit the start button and nothing happened. I tried it a couple of more times and no luck. I let off the break, hit start and it cycled through. Turned it off, waited a few minutes and pressed the brake (it actuated normally)and the jeep started. This is very disconcerting. I was hoping it was a software glitch until I hit the forums and YouTube and many owners have or had this problem.
 
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mwilk012

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If you were hoping for a software glitch, you don’t understand brake hydraulics.
 

jjvincent

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From reading your post, here are a few things is could be:

1. Vacuum leak - This could be the check valve or maybe the line going to the booster. Just maybe, your Jeep was built on a Friday with 10 minutes on the clock and Joe was thinking of the weekend and the case of Old Mil he has in the fridge at home, thus wasn't paying attention and messed something up when hooking up the vacuum lines.
2. Booster - Yes, boosters can leak. For example Ford is replacing boosters on older edges as they leak. Leak to the point where you can hear it inside the car. Thus when you turn it off, the pedal goes immediately hard. Funny part is, when you put your foot on the pedal, the leak goes away.
3. #1 and #2 plus the brake light switch. Many new mass produced cars have an automatic setting for the switch. You snap them in, pull a clip and operate the brake. It's set once and that's it. It could be not set correctly and thus you need a new switch to set it properly.

As for your grinding, just merely going by your description, your starter is bad and it will do it again and again all the way until you'll be stuck out in the middle of nowhere (because that's when things fail). Starters are not self healing.

I can tell you that on these Jeeps, I can press the brake with my left hand and use the right to start it. This is because when I do a service on one and it's on the hoist, it's easier for me to start it that way than get in it.

So, the predicament for you is to get it fixed or hope that you will get the super simple answer on the intranets and it'll all be OK. Maybe something like, "Use this simple trick to make your Jeep easier to start" Then the pic you click on will be one of a bikini clad woman standing next to a extremely modified Jeep. Then that will take you to a malware site which will get your mind off the Jeep problems.
 

XYJGuy

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If you were hoping for a software glitch, you don’t understand brake hydraulics.
The bottom line is that its a new car and if it does not start its broken. At this stage it should work 100% of the time. What makes it worse is that it is not an anomaly; its a common problem. Jeep needs to do better.
 

mwilk012

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The bottom line is that its a new car and if it does not start its broken. At this stage it should work 100% of the time. What makes it worse is that it is not an anomaly; its a common problem. Jeep needs to do better.
The thing is, it does work 100% of the time when you press the pedal hard enough.
 
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