[dr_TJ]

Originally Posted by jaideepshinh

Hi Dr_Tj,

When pressing the brake pedal, ask someone to be as close to it as possible. Do you hear a light hissing sound?

A normal failure point is the rubber seal gasket on the other side of the brake booster (where the brake pedal link connects). This usually fails before the other items you are looking at.

best of luck!

Jaideep

I did try to hear of any hissing sound when pressing the brake pedal, didn't hear any hissing sound or maybe I couldn't identify it.

Rubber seal is located on the interior?

[jaideepshinh]

Dear Dr_TJ,

The rubber seal is part of the booster assembly, and is at the firewall area on the inside. To change this, most service centers just replace the brake booster itself. In my Mercedes, this was available online as a separate part (I am not sure if Mercedes offers this as a spare to be honest).

You will need to remove the booster out to replace it. Reference photo attached.

Jaideep

[NvrGivUp]

Originally Posted by dr_TJ

But If possible, please get your vacuum check valve replaced. It might fix the issue.

Thanks a lot. Sure, will get it checked/replaced when I visit the SC.

[ph03n!x]

Hey doc! I had stopped the Thar at 2 pm yesterday, and tried the brake pedal at about 11 am. It was not rock hard, could press it. But when I started the engine, it became, as expected, normal.

Now, I've been thinking of posting the status here for days - but kept failing. Why?

My "process" of get-go in the Thar - unlock, open the door, stick the key into slot, start the engine, get in, plug in my phone for Android Auto, check if it's working (else switch off and restart!), buckle up, move.

And this invariably meant that I started the engine before checking the brake pedal for you

I'll try doing a 10 to 12 hour check soon. But I don't think you should worry much as long as braking is not compromised with the engine running. Or is there a flip-side that I'm missing?

[dr_TJ]

Originally Posted by ph03n!x

Hey doc! I had stopped the Thar at 2 pm yesterday, and tried the brake pedal at about 11 am. It was not rock hard, could press it. But when I started the engine, it became, as expected, normal.

Now, I've been thinking of posting the status here for days - but kept failing. Why?

My "process" of get-go in the Thar - unlock, open the door, stick the key into slot, start the engine, get in, plug in my phone for Android Auto, check if it's working (else switch off and restart!), buckle up, move.

And this invariably meant that I started the engine before checking the brake pedal for you

I'll try doing a 10 to 12 hour check soon. But I don't think you should worry much as long as braking is not compromised with the engine running. Or is there a flip-side that I'm missing?

I had a similar habit of just stick the key in the slot and start the engine. Wait for it to warm up a bit, get in, buckle up and drive off. Ofcourse I always check for the hand brake and AT stick in P position.
But suddenly one day I decided to press the brake pedal and start the car, and then I realised, the brake pedal was hard. Just moved enough to move the AT stick from P to N (with engine off). So, decided to check for it everytime.

After 10-12 hours of parking, my brake pedal is hard to press, just enough to shift from P to N, with the engine off.
Once I start the engine with the hard brake pedal pressed. The brake slowly moves down and is back to normal pedal travel range. Braking performance and pedal feel and feedback is absolutely normal with the engine running.

I have personally checked all the vacuum hoses and connections, all good.

In your case, 2 pm to 11 am, the brake pedal was not rock hard but was the pedal travel range normal like when the engine is running or less travel?

[ph03n!x]

So after the 11am try, I took the that out at 9am the next day. The pedal felt the same line the previous day - wasn't rock hard to press, though won't know if the brakes were actually biting (same, flat parking spot)

Originally Posted by dr_TJ

...
...
In your case, 2 pm to 11 am, the brake pedal was not rock hard but was the pedal travel range normal like when the engine is running or less travel?

After starting the engine, the pedal moves in another half or three-fourth of an inch...

[fordday]

I don't have experience of an AT car. But in MT cars brake pedal getting hard is normal after overnight parking. The vacuum remaining after engine switch off lasts for some time but eventually it gets leaked so the pedal becomes hard.

You can try this - immediately after switching off the engine try pressing the brake pedal, within 1-2 cycles it will become hard, as it 'used up' all the vacuum.

Or does the system work completely different in AT cars?

[xjosephjacob]

Originally Posted by dr_TJ

Help Needed

Dear Thar owners, as you might have seen my posts regarding my issue of brake pedal becoming stiff after overnight parking.

Why don't you visit the service centres and check the pedal stiffness in the other Thars that were parked there overnight.

[aaggoswami]

This occasionally happens in my 2012 Innova and 2014 City Petrol. Used to happen in my Swift too. All the cars are manual transmission, what I have observed is that if I switch off the engine when brake pedal is not pressed and after switching off the engine the brake pedal is not touched, it doesn't become hard. But if I switch off the engine while the brake pedal is pressed, there a few times the brake pedal becomes hard.

The overall braking performance in both my cars haven't displayed any concerns, hence never got anything checked apart from brake fluid and brake pads.

[nitkel]

Originally Posted by fordday

I don't have experience of an AT car. But in MT cars brake pedal getting hard is normal after overnight parking. The vacuum remaining after engine switch off lasts for some time but eventually it gets leaked so the pedal becomes hard. You can try this - immediately after switching off the engine try pressing the brake pedal, within 1-2 cycles it will become hard, as it 'used up' all the vacuum. Or does the system work completely different in AT cars?

I second this. In my earlier MT Fiesta the pedal immediately used to become hard after switching the engine off and it's the same case with my AT Vento too. So as long as the brakes are working after switching the engine on, I don't see any issue with the OP's Thar.