[xjosephjacob]

My 8 year old Duster 85ps has a problem related to braking (before Cold Start) which cropped up recently. The car has run 1.2 lac km so far.

Say for example I completed a trip and have parked the car in the garage overnight (in the 1st gear). The next day, before starting the car my natural tendency is to: Press the brake pedal > press the clutch > shift the gear to neutral> Turn on the key. Normally, the braking system would have just enough vacuum (or lack of it) to allow me to apply brakes once before cold starts. Only if I pump 2 or more times, the pedal becomes hard.

However recently, before I perform the cold starts my brake pedal stays rock hard. Or in other words, the braking system is unable to engage the brakes. This is a safety hazard, because if the car is parked in an incline, it would simply roll off (unless I apply the handbrakes). Once the car is turned on, brakes work just normally. There's no other easily recognizable symptoms in the braking system as I understand. No hissing sound, nothing.

Gave the car to the Renault service center, and as expected they said these are due to the car's age and mileage without pin-pointing the which exact part in the braking system is failing. They said let's get a new brake booster first (which I should pay from my pocket), and see how things are- in case problem persists, let's get to the child parts.

With this kind of response I think the folks at this service center are rather incompetent, which is why I'm reaching out to the TBHP community.

What do you think could be the root cause ?

[vigsom]

Originally Posted by xjosephjacob

Only if I pump 2 or more times, the pedal becomes hard.

However recently, before I perform the cold starts my brake pedal stays rock hard. Once the car is turned on, brakes work just normally

Brake pedal working fine after engine turning on = booster is normal.

You could just inspect the vacuum hose from the brake booster to its end connection on the engine side, and also check the hose end connections too for wear/leaks. Also please check for a minor pinhole or so on the brake booster body around the seam (unlikely you'll see this but just a possibility). I didn't expect the service center to give you a proper solution.

[Kosfactor]

Vacuum pump, reservoir , brake booster and the vacuum hoses. All these things needs to be checked by a competent mechanic.

[gkveda]

If you park the vehicle in uphill(upward slant) position, brakes becoming hard during cold start is normal. You need to worry only if the car is parked on flat position and still brakes becoming hard during cold start.

As kosfactor suggested, Vacuum pump, reservoir , brake booster and the vacuum hoses, all need to be checked, if your case belongs to second scenario above.

[Indian2003]

You dont say if this is a petrol or diesel car. If petrol it is very easy to check for leaking vacuum lines.

Let the car run on idle and spray start gas at the hose joints or where you suspect a leak. If leaking, the idle speed will go up. You need to spray on all the hoses and not only those going to the booster.

Your problem seems to be a leaking booster or hoses but i place my bet on the hose. Always check the cheapest solution when looking for faults. Dont believe what your workshop said about a faulty booster.

These are very reliable units and seldom needs replacing. The booster in my car has done 300,000 km more than yours.

[xjosephjacob]

Thank you all. I'll take the car to a FNG and get whatever you suggested rechecked for sure.

That said, I visited the Renault showroom today, and checked the brake pedals of another old Duster and a Captur (which was parked there overnight). To my surprise their brake pedals were hard too- I just couldn't pump the pedal before the cold start.

That brings me to the next question- is this normal ? Or at-least is this normal for Dusters ? In all my 1.2 lac km with this car, this is the first time I felt this as an issue. Want to bring your attention to a change that I made in my driving too- I seldom engage handbrakes nowadays when I park the car- because ever since the Covid outbreak, the running is very less and at times the handbrakes get sticky if I engage it and leave the car alone for a few days.

Are your brake pedals also hard just before a cold start ? Are you able to pump it once at least before a cold start ?

Originally Posted by Indian2003

You dont say if this is a petrol or diesel car. ...

It's a diesel.

[DheerajAggarwal]

Originally Posted by xjosephjacob

That brings me to the next question- is this normal ? Or at-least is this normal for Dusters ? In all my 1.2 lac km with this car, this is the first time I felt this as an issue. Want to bring your attention to a change that I made in my driving too- I seldom engage handbrakes nowadays when I park the car- because ever since the Covid outbreak, the running is very less and at times the handbrakes get sticky if I engage it and leave the car alone for a few days.

Are your brake pedals also hard just before a cold start ? Are you able to pump it once at least before a cold start ?



It's a diesel.

Thank you for sharing the challenge faced by you as it made me realize that mine is not just an one-off case. I have Duster RxL 85 PS Diesel 2015, driven 1,25,000 kms and I have been facing this exact same challenge from last six months. After reading your problem, I plan to get in touch with my FNG and find out exact reason and solution for this problem. Do share if your problem is resolved now.