clutch pedal on floor - perplexing lack of leaks, fluid loss, or other obvious symptoms - ??

[baldessariclan]

I'm having a perplexing issue with the clutch pedal in my 2014 TDI Sportwagen - can't figure out what's going on or what the problem might be. Here are the symptoms:

- Couple days ago, went to drive car (after had been sitting a couple days since last drive) and found that the clutch pedal was resting all the way in, up against the floor / firewall (held there by the over-center assist spring).

- Pulled clutch pedal out by hand, and found could easily move pedal in and out, with no pressure or resistance felt (other than from the over-center assist spring). The assist spring holds the pedal in either the fully extended or fully pushed-in position when I let go.

- Car was working fine before that, clutch pedal operated and felt completely normal - no degradation in performance, soft pedal, or anything like that which I detected or can recall.

- Looking up at the master cylinder piston rod area and clutch pedal assembly (from the footwell), everything looks dry - am not seeing any fluid leakage there.

- Looked down at master cylinder assembly from the engine compartment side, everything looks dry there - no fluid or leaks that I can see.

- Looking at the ground underneath the car, there is no fluid dripping or pooling under there.

- Checked the brake fluid reservoir, and it's completely full - seems to be no fluid loss there either.

So I'm at a complete loss as to explain this behavior right now. I mean, moving the pedal in and out by hand, I feel absolutely no resistance or pressure buildup in the clutch system (other than from the pedal assist spring). It sort of feels almost like there's no fluid in the master cylinder at all, and/or it's completely dry. But once again the brake fluid reservoir is still completely full, and I'm not seeing leaks anywhere - ??

So anybody ever have similar issues, and/or ideas about what might be going on???

 

[pipesta]

Had that happen last year and ended up replacing the slave cylinder. I did try bleeding the clutch and that lasted about a week or so. The slave is very common on these vehicles.

 

[DSIre]

The supply line from the brake resevoir to the clutch master cylinder is almost at the top, so it may look full, but not cover the nipple. Bring fluid level to the very top and open the bleed valve on the clutch slave line. It will gravity bleed. If that does not help, your slave cylinder/release bearing may be leaking (it will drain out the gap between the engine and transmission.)
I had to pull two transmissions so far this year of family members cars with leaking slave cylinders (2007 EOS and 2012 JSW) and will have to do a third in a week or two.
Good luck.

 

[baldessariclan]

Ok, will try bleeding first, when can get it moved into location where I can work on it.

Note that the fluid level in the brake reservoir was indeed well above the nipple for the clutch master cylinder supply hose when I checked, so am still a bit baffled by the symptoms. Definitely not seeing any fluid loss or leaks so far, so not exactly sure how or why it could behave this way -- ??

Only other thing I can think of is that the clutch pedal has always had a slight squeak when applied, so I had asked local mechanic to try lubing it when they were doing some other work a couple months ago. Am now wondering if they maybe they got some oil or grease into the master cylinder piston area, and that might have affected it, or caused issues with seals (e.g. swelling), perhaps? Once again, though, not seeing any signs of leaking when I looked up in there. Hmmm...

 

[pipesta]

FWIW mine had no signs of leaks when the slave went out. It was all inside the bellhousing and never made it out.

 

[baldessariclan]

pipesta, did you notice if the fluid level in your brake fluid reservoir had gone down at all, or if it was still basically full when your slave cylinder failed?

 

[IndigoBlueWagon]

As posted above, clutch slave cylinder failure is common on these cars. Unfortunate, as you have to remove the transmission to replace it, unlike on the 5 speed cars where it sat outside the transmission (and didn't fail as often) It may be letting air into the system, so fluid level might not change much, if at all.

 

[baldessariclan]

Ah, gotcha - thanks! Well, will go through the steps from easiest/cheapest to hardest/$$$ and see where they lead. Sounds like there may indeed be a clutch slave cylinder replacement in my near future, though... :-(

 

[pipesta]

pipesta, did you notice if the fluid level in your brake fluid reservoir had gone down at all, or if it was still basically full when your slave cylinder failed?

Nothing noticeable at the reservoir.

 

[baldessariclan]

Update: Finally got around to bleeding the clutch hydraulic system, which gave me my clutch pedal back. But the process also produced a small puddle of brake fluid on the ground, dripping from the most dreaded location — bottom of transmission bell housing. So as you guys correctly predicted, seems to be a bad slave cylinder - *sigh*.

Next question - I have heard there are a couple different types of slave cylinders available for this model, one w/ plastic body, and other w/ metal body - ? If so, any word on which is better / more reliable in the long run?

 

[nokivasara]

Update: Finally got around to bleeding the clutch hydraulic system, which gave me my clutch pedal back. But the process also produced a small puddle of brake fluid on the ground, dripping from the most dreaded location — bottom of transmission bell housing. So as you guys correctly predicted, seems to be a bad slave cylinder - *sigh*.

Next question - I have heard there are a couple different types of slave cylinders available for this model, one w/ plastic body, and other w/ metal body - ? If so, any word on which is better / more reliable in the long run?

Are you sure the puddle is not from the bleeding?

I had to replace the clutch master cyl in my Tiguan and it's common for them to fail in the way you describe, the pedal sticks to the floor but works fine for a while after bleeding. As DSIre pointed out above, the clutch pipe nipple in the brake master cylinder is very high up. Much higher than you'd think when looking at it. It's like the clutch has its own compartment inside the reservoir and that can be almost empty while the level is OK for the brakes.
I made sure that the level was way over the MIN mark and a hard time bleeding the clutch. Then I filled the reservoir to the brim and had no problem bleeding it.

 

[tactdi]

I wish I could tell you that metal is better. BUT, I had a metal slave cylinder leak after a couple of years. Pulled the trans and ordered
a new slave, which was a plastic one. No problems with the plastic one for the past couple of years. I would think as long as you get
OE or OEM, quality would be the same.

 

[baldessariclan]

Took my car to our local independent VW specialist mechanic couple days ago. He pulled the transmission this morning, and confirmed that it was indeed my slave cylinder which was leaking.

I asked him about the metal vs. plastic bodied slave cylinders, and he said that in his opinion it didn’t really matter, since it is usually the seal in the cylinder which fails, and not the body. He said there are a couple different OEM suppliers who make that part, and quality should be fine w/ either.

One good bit of news is that said he was pleasantly surprised to see how good my clutch and flywheel looked - very little wear, no blue or burned spots, warping, etc. Car only has about 45k miles on it (and I’m fairly laid-back driver, to boot), so expect can probably reuse those components again, as-is.

Thanks again to everybody for all the help and guidance on this one! I really was pretty bewildered by it all, especially in the beginning.