Team-BHP - Clutch pedal sinking

Hi , I have a 5 year old S-Cross 1.6. The car has relatively been trouble free, but in the last 1.5 years has not seen too much mileage. I do take it out at least once a week for an hour or so.
I've had the clutch pedal sinking twice while driving - thankfully at slow speeds. Both times I have been able to lift up the pedal and continue, but i am really worried on this. It drives reasonably well and there's no loss of power when it is working.

Any likely hints on what could be going wrong? Previous forum posts on other vehicles have indicated everything from full clutch replacement to master/slave cylinder replacement etc.
Appreciate any information on this.

Quote:

Originally Posted by ballkey (Post 5103920)

Any likely hints on what could be going wrong? Previous forum posts on other vehicles have indicated everything from full clutch replacement to master/slave cylinder replacement etc.
Appreciate any information on this.

The classical symptom of a failing master cylinder is the erratic behavior of the clutch pedal. For e.g. the clutch will sink and not return back.

Get the master cylinder checked.

Quote:

Originally Posted by abhishek46 (Post 5103942)

The classical symptom of a failing master cylinder is the erratic behavior of the clutch pedal. For e.g. the clutch will sink and not return back.

Get the master cylinder checked.

Thanks, is it safe to drive for a bit? or can it break other things? I understand the risk of driving with possibility of losing the clutch..

Quote:

Originally Posted by ballkey (Post 5103920)

Since you have some idea of the bits that needs replacement, allow me to motivate you.

This problem is caused by disuse often, and when it works it works as if nothing happened until you happen to be in a hill station on a busy weekend and the clutch gives up! I know a vehicle like this that gets used very little, a few years ago it caused a massive traffic jam in Nandi hills , it is still running on the same master cylinder though barely , a ticking time bomb or a road block of some sort.

Replace immediately please.

Quote:

Originally Posted by ballkey (Post 5103962)

Thanks, is it safe to drive for a bit? or can it break other things? I understand the risk of driving with possibility of losing the clutch..

You can drive however long you want. It will not brake other things. But, just like you experienced, the clutch MC failure will be sudden and you might be stranded. So, choose if you want reliability or profitability.

Quote:

Originally Posted by dhanushs (Post 5103992)

the clutch MC failure will be sudden and you might be stranded. So, choose if you want reliability or profitability.

Oh dear, i wish i had know this before. same thing happened to me.
This behavior started on my fortuner and every time the service center managed to bleed the clutch and restore the soft clutch to brand new level . But it would keep getting hard in a few months and rarely would stay depressed during the use till you manually lift it up . i suspects few other people who drove the car beside me would continue to drive just like that that result in heavy stress on clutch /gear assembly.

Then one fine day while en route to Goa from Bangalore on really traffic less ghat The clutch gave up. Goa was still around 200 Km nd i remember taking close to 7 hours to cover that distance with the car getting stuck in some gear / Neutral randomly.:Frustrati.
That was the only time Fortuner let me down onroad in a decade of ownership.:sadface

Quote:

Originally Posted by ballkey (Post 5103920)

It's the slave cylinder slowly starting to pack up. The labour cost is around 5k. If yours is a high mileage car, better to do clutch overhaul along with it since labour is the same.

I took it to MsM chennai - there appears to be some oil leakage , indicating slave cylinder failure. The service advisor says the entire clutch assembly need to be replaced including the flywheel.. about 55k.🥺
The service advisor says slave cylinder failure could have leaked oil iinside and the plates could also be affected. I have asked him to inspect thoroughly after lowering the box. Will keep you folks posted

Quote:

Originally Posted by ballkey (Post 5104297)

I took it to MsM chennai - there appears to be some oil leakage , indicating slave cylinder failure. The service advisor says the entire clutch assembly need to be replaced including the flywheel.. about 55k.��
The service advisor says slave cylinder failure could have leaked oil iinside and the plates could also be affected. I have asked him to inspect thoroughly after lowering the box. Will keep you folks posted

That's the ideal procedure, in an Old car is CSC/Clutch Slave Cylinder gives away, ideally you replace the whole clutch.
I had got it done in one of my cars few years ago, including Dual Mass Flywheel.

Does Scross 1.6 comes with DMF/Dual Mass Flywheel?

Quote:

Originally Posted by ballkey (Post 5104297)

A quick search on Boodmo for the prices, here's what I got:

Part No.: 22000M55LA1
Part name: Clutch Assy (Clutch plate + pressure plate)
Price: ₹13,325

Part No.: 23820M79J00
Part Name: Cylinder Assy, Clutch Slave
Price: ~₹2,500

Part No.: 22113M55LA0
Part Name: Bolt, Clutch Cover (6 no's)
Price: ₹ Not available

Part No.: 12620M55P00
Part Name: Flywheel
Price: ₹27,985

You'll need to add Transmission Oil and labour charges too to the above part prices that will make the bill value to about ~55,000 as informed by the SA.

First, you should get the whole hydraulic line bled with new brake fluid while opening both Slave & master cylinder's bleeder valve & pumping the pedal. It's a two men job or could get it done from a reliable garage. If that doesn't work, you will have the same issue again only after you park your car for a while, say overnight then get both cylinders removed by a mechanic one by one first the master then the slave in the same sequence. He will check for any air leaks or whether any fluid pressure is getting pumped he can easily check it & replace the one failing. As only sometimes it get depressed & as you will press the clutch a few times hard, it comes back up it must be the slave but as a precaution I will change both, if one failed to keep my ride's reliability. after replacing get them bled good & make sure the whole hydraulic line is tightened well & bleeder valves are closed properly as brake fluid is hygroscopic it absorbs moisture from air easily esp monsoon rains when we drive from water filled roads the clutch pedal becomes hard.
hope this helps.

Quote:

Originally Posted by ballkey (Post 5104297)

I took it to MsM chennai - there appears to be some oil leakage , indicating slave cylinder failure. The service advisor says the entire clutch assembly need to be replaced including the flywheel.. about 55k.��
The service advisor says slave cylinder failure could have leaked oil iinside and the plates could also be affected. I have asked him to inspect thoroughly after lowering the box. Will keep you folks posted

Unless the clutch plates are covered/contaminated with the hydraulic oil, there is no need to change the clutch. And flywheel will not get impacted with a leaking clutch slave cylinder. Just get the slave cylinder replaced and bleed the clutch and you should be good to go. Be with the service center when they open the clutch housing to check if the hydraulic fluid has seeped inside and over the clutch plates

The service center is taking you for a ride. In these Covid times, this has become a trend. Due to lack of business, the service centers are suggesting part replacements left, right and center. Just last week, I was asked to replace the entire right side suspension components - Lower arm, tie rod, link rod, strut- when I complained of noise from front right area, whereas the cause was because of the strut leaking and all other components being all right. One has to be very cautious in these times with the service centers.