[dr_TJ]

So, I took delivery of a Jimny Alpha AT on 2nd of July. Owing to discounts on MY2023 Jimnys. Mine is September 2023 Manufactured.
PDI was done. But my bad, I couldn't detect the problems that I am facing now.

So, the Jimny brake pedal goes hard after the car is parked and engine is switched off.

I know, once the engine is switched off, with no active vacuum generation from the intake, the car brake booster will eventually run out of vacuum or if we pump the brake pedal 3-4 times with the engine switched off. Then the brake pedal goes hard.

But in my case, the brake pedal goes hard after I park my car, switch off the engine. I have not touched the brake pedal after the engine was switched off. I would have been ok if the pedal went hard to press after 2-3 days of inactivity. But in my case, the pedal goes hard in less than an hour of parking the car.

Once I press the hard brake pedal and start the engine. The brake pedal depresses and works like normal. Although I feel the braking happens with the pedal pressed 80-90%. Stopping power feels good but not much of stopping power is felt with just a slight press of the brakes. Maybe this is normal, I am not sure.
But the brake pedal going hard in under 1 hour of inactivity is not normal for sure. I suspect a faulty check valve or a failing brake booster. Also. I don't stay in some high altitude location so thin atmosphere and so less vacuum can't be blamed.
I have been driving the car since the weekend only. At first I thought I might be overthinking or might have made a mistake but no, sadly, it has this problem.

Now, the second issue is the wheel alignment. The car has a left pull. With the steering at the center, the car just fails to go straight. It pulls to the left. I thought this might be because of the slant of our road from the divider to the left of the road but on flat road, I do find steering wheel not pointing straight when I Intend to go straight albeit to a lesser degree.

I will send my car to Nexa service tomorrow. Will update here.
Any other BHPian facing similar issue?

[Bsilver]

I don't get what is the problem here with the vehicle. If it is not showing any signs of any failure when the engine is running, and is functioning properly then there is no need to worry about it.
The pedal going hard is normal in all vehicles, unless there is a fault with the braking system or non functional pedal assist at engine running, then you may need to look into it, until then why bother if functioning properly.

A proper alignment and road force balancing can fix the issue with the car pulling to the left, if after doing this, if it continues to pull to any direction then you need to look into the steering track rods, suspension etc. But try to get the basics correct at the first place to eliminate any other issues.

Happy Motoring!

[saket77]

1. Check valve vacuum pipe.
2. Leakage from brake booster.

I can think of these two. Please update us when you get a diagnosis done.

Thanks.

[dr_TJ]

Originally Posted by Bsilver

I don't get what is the problem here with the vehicle. If it is not showing any signs of any failure when the engine is running, and is functioning properly then there is no need to worry about it.
The pedal going hard is normal in all vehicles, unless there is a fault with the braking system or non functional pedal assist at engine running, then you may need to look into it, until then why bother if functioning properly.

A proper alignment and road force balancing can fix the issue with the car pulling to the left, if after doing this, if it continues to pull to any direction then you need to look into the steering track rods, suspension etc. But try to get the basics correct at the first place to eliminate any other issues.

Happy Motoring!

Yes, with engine running, it seems to work normally.
Thing is, A brake system loosing all its vacuum in under 1 hour is not normal for sure. I would not have worried if other Jimnys in my friend circle were showing similar behavior.

As per as alignment is concerned, its a hit and miss at stand alone alignment shops outhere. All depends on do they have Jimny specific data available with them or not and can they fix the alignment of a front solid axle vehicle. Will give Nexa service a chance

Originally Posted by saket77

1. Check valve vacuum pipe.
2. Leakage from brake booster.

I can think of these two. Please update us when you get a diagnosis done.

Thanks.

Yes, I suspect the same.
Will surely update here.

If Nexa service guys don't act well, I will have to push my case with the Maruti higher ups

[dhanushs]

Umm. Can you elaborate your problem. Brakes getting hard when switched off is not a problem as you are not supposed to do that.

[nova.19_exe]

Okay, I don't see a problem with this. My dad's 2004 Elantra GT also has this phenomenon!

When I asked my dad about this, he said it's due to ABS, IIRC.

It's not a big deal. This is normal behavior.

[NomadSK]

Originally Posted by dr_TJ

So, the Jimny brake pedal goes hard after the car is parked and engine is switched off.

This is quite normal in my opinion. Power brakes uses vacuum power from the engine's RPM to multiply the force applied to the brake pedal.

But in my case, the brake pedal goes hard after I park my car, switch off the engine. I have not touched the brake pedal after the engine was switched off. I would have been ok if the pedal went hard to press after 2-3 days of inactivity. But in my case, the pedal goes hard in less than an hour of parking the car.

As soon as the engine is switched off, the pedal would get hard immediately with no vacuum power.

During engine running, Only If the brake booster fails or if there is a vacuum leak, it will not work properly, resulting in a hard brake pedal. Even if it fails, you will still be able to brake, but only with your own physical strength, although that's very unsafe to do so.

[swiftLife]

This is indeed a problem. I have an 18+ year old Swift. And in that from as far as I can remember, the brake vacuum used to hold for an extended period of time (more than a few days, maybe even longer, I don't even remember).

But then later with age the duration went down. To me it didn't matter that much as the vaccum builds up as soon as I start the car. I know there must be some small leak but IMO it's expected given the age.

And I'm fully aware that with the engine off, the vaccum assist goes to 0 after pushing the pedal 3-4 times and makes the pedal very hard. But the pedal is supposed to retain the vacuum for the first push after an engine shut-off for some amount of time. Less than an hour is definitely abnormal.

In your case, like saket77 suggested, there is definitely a leak somewhere. And as this is an abnormal behavior given the car is new, strongly suggest to get it checked.

[saket77]

Originally Posted by swiftLife

This is indeed a problem. I have an 18+ year old Swift. And in that from as far as I can remember, the brake vacuum used to hold for an extended period of time (more than a few days, maybe even longer, I don't even remember).

But then later with age the duration went down. To me it didn't matter that much as the vaccum builds up as soon as I start the car. I know there must be some small leak but IMO it's expected given the age.

In your case, like saket77 suggested, there is definitely a leak somewhere. And as this is an abnormal behavior given the car is new, strongly suggest to get it checked.

Yes, the system keeps 2-3 pumps in 'reserve' by design by way of holding up vacuum even if the engine is off through a non-return valve in the vacuum pipe connecting the brake booster and the engine intake manifold. A leak in the system or a bad valve will result in such a scenario described by the OP.

You obviously don't want to lose all braking power suddenly if you happen to stall the engine on road.

[dr_TJ]

Originally Posted by dhanushs

Umm. Can you elaborate your problem. Brakes getting hard when switched off is not a problem as you are not supposed to do that.

As I have said. Once engine is switched off, the brakes can be pressed 3-4 times before the vacuum runs out. In my case, if I park my car and don't even touch the brakes, after 1 hour, the pedal is hard to press cause no more vacuum. Its definitely not normal for the vacuum assist to run out in less than an hour unless there is some leakage.

Originally Posted by nova.19_exe

It's not a big deal. This is normal behavior.

Originally Posted by NomadSK

This is quite normal in my opinion. Power brakes uses vacuum power from the engine's RPM to multiply the force applied to the brake pedal.
As soon as the engine is switched off, the pedal would get hard immediately with no vacuum power.
During engine running, Only If the brake booster fails or if there is a vacuum leak, it will not work properly, resulting in a hard brake pedal. Even if it fails, you will still be able to brake, but only with your own physical strength, although that's very unsafe to do so.

I fail to understand how this is normal? Vacuum assisted brakes and a brake booster is designed for 3-4 vacuum assisted presses with engine switched off. In all my previous cars (expect my Thar Diesel but got it fixed after replacement of vacuum pump and check valve), the brake pedal was good to press down even after 2 days of parking the car. In the Jimny, the vacuum is depleted in under an hour. We have a few Jimnys in my local car group, none of them has this problem so something is definitely not quite right.

Originally Posted by swiftLife

And I'm fully aware that with the engine off, the vaccum assist goes to 0 after pushing the pedal 3-4 times and makes the pedal very hard. But the pedal is supposed to retain the vacuum for the first push after an engine shut-off for some amount of time. Less than an hour is definitely abnormal.

In your case, like saket77 suggested, there is definitely a leak somewhere. And as this is an abnormal behavior given the car is new, strongly suggest to get it checked.

You have absolutely nailed my point. This is exactly what I am thinking. This is certainly not normal.

Originally Posted by saket77

Yes, the system keeps 2-3 pumps in 'reserve' by design by way of holding up vacuum even if the engine is off through a non-return valve in the vacuum pipe connecting the brake booster and the engine intake manifold. A leak in the system or a bad valve will result in such a scenario described by the OP.

You obviously don't want to lose all braking power suddenly if you happen to stall the engine on road.

And the system is working normally with the engine on, but we never know when it might spring a nasty surprise on the road.

My only concern is dealing with the Nexa service guys. I know, first thing they will say is "This is Normal sir" and try to brush it off. A real headache to make them understand the issue.

[AMG Power]

1. Nothing wrong with your brakes. If your car brakes well when you’re driving and there are no issues at all leave the brakes alone. Fiddling with a properly working brake system may potentially lead to other issues.

2. Check your wheel alignment and / or whether your tyre(s) have deformed during long term parking at the yard. Also have the suspension checked for issues that could lead to the pull.

[NomadSK]

Originally Posted by saket77

A leak in the system or a bad valve will result in such a scenario described by the OP.

I’m not sure, but logically any leak of vacuum or a diaphragm gone bad in a booster pump would trigger ABS light.

[saket77]

Originally Posted by NomadSK

I’m not sure, but logically any leak of vacuum or a diaphragm gone bad in a booster pump would trigger ABS light.

Na, don’t think so. ABS light is related to only ABS malfunction. Vacuum pipe is part of basic power braking system.

[dhanushs]

Originally Posted by dr_TJ

As I have said. Once engine is switched off, the brakes can be pressed 3-4 times before the vacuum runs out. In my case, if I park my car and don't even touch the brakes, after 1 hour, the pedal is hard to press cause no more vacuum. Its definitely not normal for the vacuum assist to run out in less than an hour unless there is some leakage.
.

I fail to understand.. After you switch off.. and park the vehicle for 1 hour, why do you need assist in your brakes? Can you elaborate "Functionally" in using the vehicle for all intended purposes, where you are facing a problem?

[arjab]

Originally Posted by dr_TJ

So, the Jimny brake pedal goes hard after the car is parked and engine is switched off.

Brake fluid, by nature, is highly hygroscopic, (i.e. attracts moisture). Your vehicle was manufactured in 2023 September and had been standing in the dealer stockyard for quite some time. There may be chances of atmospheric moisture affecting the existing brake fluid leading to some formation of air in the hydraulic lines.
It may be worthwhile to drain out your vehicle's existing brake fluid, bleed the brake circuit thoroughly and re-fill with fresh brake oil.

Originally Posted by dr_TJ

Now, the second issue is the wheel alignment. The car has a left pull. With the steering at the center, the car just fails to go straight. It pulls to the left.

Jimny's do not have a left pull. Due to the ancient recirculating ball steering system that the Jimny comes with, the steering wheel has a good deal of "free play" on either side from the 12'o'-clock position. Actually the "actual centre point" of the Jimny steering is when the steering wheel is tilted slightly to the right!
Since we are used to driving with much direct power assisted rack & pinion setup's in hatchbacks/sedans and soft-roaders, our mind struggles to accept this "tilt" as "straight" !
But fear not. You can correct this, albeit you need a skilled technician who has worked with this kind of a steering system to know the nuances of adjusting it properly.
1. You can adjust the "steering centering" by adjusting the front track control rod from below the car. This should solve the centering issue to a large extent.
2. The 2nd way to do it: is to reset the steering angle sensor. Here you need a brainy guy to do the job. He has to measure the "angle of tilt" in degrees towards the right, usually it is around 7-8 degrees. Then the technician has to centre the steering wheel in the 12 o'-clock position and tilt it by exactly the same number of degrees to the opposite side, in your car it will be, left. Then the steering angle sensor needs to be reset, so that it "thinks" that this is a left tilt and "pulls" the steering to the centre.

And yes: congratulations on your purchase. The Jimny is car with character and will make you work hard to enjoy it. Keeping all its foibles & quirks in mind you will be grinning from ear to ear as to its capabilities when the going gets tough.

Drive safe & Happy Motoring!