1998 Alfa 156 2.5 v6 - clutch noise / vibration
Discussion
A couple of mates and I are doing up an old 156 2.5 V6 with a view to turning it into a cheap track hack and we've run into a weird problem.
One of the reasons we got it cheap was that the gearbox was noisy. We bought a secondhand gearbox and replaced it, fitting a new clutch and release bearing while we were in there (Valeo branded). Gearbox oil was renewed, and the level carefully checked once all in situ. We completed this work a couple of months ago, and have done a couple of short test runs where all seemed well. Beautiful light clutch pedal, very progressive take up of drive, nice gear change quality, and no odd noises or vibrations. In short, just how you would expect a new clutch to feel.
More work was pending (urgent timing belt required) so the transmission stuff was ticked off the list, and the car was laid up for a bit pending time and parts. We've just completed the timing belt work this evening, and took the car out for another run to check all was well. It was to start with. Then, after a mile or so we noticed a light metallic rattle/clatter audible over the general engine and road noise. This clatter stops the second any pressure is put on the clutch pedal. The clutch pedal itself is still light, but now the bite point is right on the floor and instead of being progressive as it was, engages very roughly and abruptly. The car does still drive, but something is clearly quite seriously wrong.
Losing light (and getting tired), about all we had left in us was to we bleed the clutch at the slave cylinder. It seemed to have a little air in it, but this hasn't made any difference.
The noise is present in all gears with the clutch pedal released whether under drive conditions, on the overrun, or just idling in neutral. If you just touch the clutch pedal and depress it even a mill or two, the noise stops, even though drive remains to the transmission.
Any suggestions welcome. This doesn't fit with any kind of clutch problem I've seen before.
Cheers in advance
One of the reasons we got it cheap was that the gearbox was noisy. We bought a secondhand gearbox and replaced it, fitting a new clutch and release bearing while we were in there (Valeo branded). Gearbox oil was renewed, and the level carefully checked once all in situ. We completed this work a couple of months ago, and have done a couple of short test runs where all seemed well. Beautiful light clutch pedal, very progressive take up of drive, nice gear change quality, and no odd noises or vibrations. In short, just how you would expect a new clutch to feel.
More work was pending (urgent timing belt required) so the transmission stuff was ticked off the list, and the car was laid up for a bit pending time and parts. We've just completed the timing belt work this evening, and took the car out for another run to check all was well. It was to start with. Then, after a mile or so we noticed a light metallic rattle/clatter audible over the general engine and road noise. This clatter stops the second any pressure is put on the clutch pedal. The clutch pedal itself is still light, but now the bite point is right on the floor and instead of being progressive as it was, engages very roughly and abruptly. The car does still drive, but something is clearly quite seriously wrong.
Losing light (and getting tired), about all we had left in us was to we bleed the clutch at the slave cylinder. It seemed to have a little air in it, but this hasn't made any difference.
The noise is present in all gears with the clutch pedal released whether under drive conditions, on the overrun, or just idling in neutral. If you just touch the clutch pedal and depress it even a mill or two, the noise stops, even though drive remains to the transmission.
Any suggestions welcome. This doesn't fit with any kind of clutch problem I've seen before.
Cheers in advance
Thanks gentlemen. I must admit the thought of removing that gearbox again brings me out in hives. It was an epic job. I've had release bearings go before, but they have made a noise when the pedal has been depressed rather than released.
Any idea why the release bearing would fail within, at the most, half a dozen miles of being fitted? I'm never closed to the idea that we made a mistake, but we are fairly experienced DIY mechanics and have done this sort of job before on other cars.
Any idea why the release bearing would fail within, at the most, half a dozen miles of being fitted? I'm never closed to the idea that we made a mistake, but we are fairly experienced DIY mechanics and have done this sort of job before on other cars.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff