Hard Brake Pedal

[phoebe]

Hi

New member and have not found an answer by searching so far.

I have a 2017 plated Triton Exceed purchased new from dealer in March 2018. On about 6 occasions since purchase, after parking the vehicle overnight and trying to start it first up next morning, the brake pedal is rock solid and will not depress enough to allow the vehicle to start. It takes several attempts pressing and repressing the start button before it final kicks.

Three mitsubishi dealers (here in Australia) that I have contacted have never heard of this problem and it is almost impossible to replicate as it is so infrequent.

Has anyone ever had this experience?

[WUNSIE]

Sounds like whats happening is the vacuum in the brake booster is being depleted whilst sitting overnight, easy to replicate at the dealer, with the engine off just pump your brakes 4-5 times and you will feel the pedal get hard as buggery as the vacuum assistance is being used ( so to speak)
Then have the service big wig come out and try to start it as you have described

[Rhamer]

Mine does that too sometimes, but never enough to stop me from being able to start it.

I also noticed that the vacuum boost only seems to last about 1 brake application when the engine is off.

Occasionally I have pressed the brake after parking with the engine off and fiddling around looking for something before getting out, usually resulting in a hard pedal when returning.

Pay attention to the sequence you perform when parking, perhaps you are doing the same.

Rohan

[phoebe]

Thanks for the responses

I will try what you both suggest. I rang three different dealers and spoke with three service managers and all plead ignorance as far as other owners reporting similar issues - I cant be the only one.

One SM suggested vacuum, and one suggested the sensor in the switch that communicates between brake and starter.

Being such an intermittent problem it may be under reported, if at all.

[durphurpin]

Mine is a 2017 plate Exceed as well, does the same thing had to try 3 times to get it started yesterday morning

[Genebaby]

Only had ours for 8 days now but I've not experienced this.

[andelect]

mine starting having hard pedal after 18months, and I just push brake pedal harder to start. Like others, occurs mostly after sitting o/night or lengthy period. It did catch my son out, who rang to say he couldn't start car. It actually requires a fair foot pressure to get the pedal to move so the car can start, and I bet my better half would have some difficulty. Might ask my mechanic tomorrow.

Update. Well I did ask the mechanic, who just said is probably loosing vacumn after long period of time. He's also got a MN and said this has never happened to him, and I get the feeling no one asked him this before. Just made the suggestion he will look at other MQ's when they come in the shop. I don't I will get an answer here.

[RHKTriton]

I see a 'boffins failure' coming up.

These safety interlocks should always have an override function.

Can these vehicles still be started with a key, or is the button the only option?

[Genebaby]

Hmm, I actually got this this morning. It was definitely harder than usual, but I was thinking of this thread and gave it a good push and all was good.

I would hope it would always be possible, for ladies especially, to be able to start the car.

There might be a way to do it by putting the key unit thing into the dashboard?

[andelect]

From the Workshop manual. I'll try this weekend.....if I can start the car.....

1.Carry out the simplified brake booster operation check in the following procedure:
(1) Run the engine for 1 to 2 minutes, and then stop. Depress the brake pedal with normal depression force. The result is judged as "Good" when the pedal stroke is great at the first depression, and becomes smaller as you repeat depressing the pedal. If the pedal stroke does not change, the result is judged as "No Good."
(2) With the engine stopped, depress the brake pedal several times. Keep the brake pedal depressed and start the engine. At this time, when the pedal moves down slightly, the result is judged as "Good." The result is judged as "No Good" if the pedal does not moves down.
(3) With the engine running, depress the brake pedal. Stop the engine in this condition. The result is judged as "Good" when the pedal height does not change for approximately 30 seconds. The result is judged as "No Good" if the pedal moves up.
2.The brake booster is judged as normal when the results of all the above checks are "Good."
When one or more of the above check results are "No Good," then the check valve, vacuum hose, or brake booster is suspected faulty.