A Fluid Level I forgot to Check

Posted on November 29th, 2007 in Driving Emotion by Julian Edgar

insight-clutch-reservoir.jpgHad a problem with one of my cars yesterday.

My wife, who had been driving the Honda Insight, had previously questioned me about the clutch feel.

“It’s awfully light,” she said. “And it seems to engage right on the floor.”

Dismissing this with a wave of my hand (I figured she’d just been driving the much-heavier-clutch Peugeot diesel too much), I thought no more of it until I got into the Honda and the clutch pedal went straight to the floor. No gear selection was possible, so clearly the clutch was no longer disengaging.

Paradoxically, despite the engine’s low absolute torque output, the clutch in the Honda has a hard time. This is because the gearing is so high – to move away from a standstill, the clutch always needs to be slipped. So although it doesn’t have a lot of kilometres on it, the clutch is starting to wear, juddering a little if the take-up is not got exactly right.

So when the clutch failed to work at all, I suspected the worse – perhaps the spring fingers had collapsed or something.

But the first step was a careful underbonnet inspection. There I discovered that the clutch uses a hydraulic actuation system – and the reservoir was empty! Hmm. I filled the system with Dot 4 brake fluid (as specified) and then bled it.

And then – what do you know – the clutch worked again!

So where had the fluid gone? There was a slight moistness around the slave cylinder, probably enough of a weep that over time the fluid level could have lowered itself sufficiently to start drawing air.

You see, I’d never – not once – checked the level of fluid in the clutch master cylinder reservoir. Not once.

So if you’re as dumb as I am, and your car has a hydraulically-activated clutch, you might need to be reminded to check its fluid level…

One Response to 'A Fluid Level I forgot to Check'

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  1. OttoAu said,

    on November 29th, 2007 at 7:04 am

    Had similar issue.

    Was doing a oil/filter change in the X Trail and noticed the brade fluiud was very low.

    Took the wheels off to check the wheel-cylinders and check for leaks…Nothing.

    Then i noticed the front pads where shot/worn [only 38,500km] so now that inc. a pad change up front too[rears ok]

    After the job was done and pumped the brake pedal, the oil came back:-)

    Its a nice vehicle the X Trail, but our next will be the CX7 by Mazda, its only around 15% more.

    Hope you guys get to test the CX7 some time soon



  2. Monty said,

    on November 29th, 2007 at 6:09 pm

    I’ve had the same happen on a DC2 integra. Driving across the Sydney Harbour Bridge the pedal dropped to the floor as the air got sucked into the lines. We rolled through the toll gates and down the closest exit I could find. A quick diagnosis by the side of the road and a consult of the manual identified the lack of clutch fluid. We borrowed a tool to open the bleed point off a nearby motorist, a friend dropped off some brake fluid and we were away again!
    I think my error was the same as yours – I failed to check the fluid level in the 6 months prior to that incident. All my earlier cars had cable based clutches.

  3. Mal said,

    on December 4th, 2007 at 3:38 pm

    If you have to pump the brakes to make them start working again you have air in the lines.
    Bleed the brakes…

  4. OttoAu said,

    on December 10th, 2007 at 10:26 am

    The only reason i had to pump the pedal was the calipers where spread out to the max [so i could remove the shot-pads]
    The pedal then reached the normal level, it stops and works fine!