MBOmaha

Only my second post, but alas, I have searched the forums and found nothing definitive on this subject.

I just bought my 2009 C300 Sport within the last month, with 33k miles on the clock. It shifts buttery smooth, clutch pedal feels just right for the application, and I hadn't noticed anything out of the ordinary until this past weekend. It was my first out-of-town trip, but only about 30 miles of steady highway driving one way.

The first time I pushed in the clutch pedal while coming to a stop at the off-ramp, the clutch action was really stiff. It was reminiscent of my hi-performance, cable-actuated clutch in my old 89 Mustang. It was stiff for the next few disengagements, then felt okay again. When I made the trip home, it did the exact same thing. It always shifts fine, just the really stiff pedal. It hasn't done it again, but then, I haven't left the city. I drive this car to work every day.

I have searched Google, searched technical bulletins and the like, but I haven't seen anything definite on the cause. Any ideas? My biggest fear is that there is pressure "pump-up" in the line, and that can cause partial disengagement of the clutch, leading to throwout bearing or clutch failure. I'd like to avoid that.

What say you?

Sportstick

It's about the age and mileage of the car I just sold. Every two years, I had the fluid in the line changed when the brake fluid was changed. Most folks never think to do this, and each time, the clutch action improved (albeit subtly) when the fluid was replaced. You may have 5 year old fluid. I suggest you have that changed in any event and then reassess the car's behavior.

MBOmaha

Thanks for the quick response. I was considering exactly this. At the very least, it's the lowest-cost option to try in chasing this issue, and likely an overlooked maintenance item as well. Great suggestion.

MBOmaha

Just wanted to follow up on the fix. There is a TSB out there for "slow clutch pedal return". It calls for replacing the hydraulic clutch line at the transmission. Because the pedal did exhibit this in addition to the hard pedal, I went ahead and bought the new line. After installation and bleeding, it's been fine since. When I get time I'm going to cut the old line in half. I suspect that the inner rubber part of the hose has separated and is collapsing, causing fluid flow problems. I'll post up pics when I do.

Doanster

Thanks for the update! No issues so far for me, but will definitely file this post away...

gary_youngster

I’ve been driving my 6-speed for the past 11 years and I don’t recall I’ve ever changed the clutch line fluid. Shortly after the lockdown around last year, I started the feel that my pedal is relatively harder to press when exiting the freeway. I will try changing the fluid first and see how it goes.