1985-1998 [Subscribe to Daily Digest] |
That bellows and its spring are as an ant to a locomotive compared to the pressure plate springs.
The throwout bearing sits on a shoulder on the nose of the slave cylinder, on an inner hardened steel sleeve that is officially called the piston, as it's what moves when pushed by hydraulic fluid, displaced out of the master cylinder by the push of your left foot. As fluid flows into the slave it pushes the piston towards the pressure plate and the piston pushes the throwout bearing and that pushes the center of the fingers of the pressure plate (serious pressure here, very strong springs) in, and they release at the outer ends and let off pressure on the forged steel disk that contacts the clutch disk's outer friction surface and holds the disk and its inner friction surface captive between it and the flywheel's machined surface.
Pressure released, driving force is off the clutch disk and the input shaft to the tranny, that's splined to the disk's inner hub. So the disk slides between the two faces until you let off the pedal, when the pressure plate's spring fingers move back towards the slave cylinder, pushing the throwout bearing, and pushing the piston back home into the slave, and the fluid back up the line, and the clutch master back to resting position, and the pedal back up. (There's a little return spring on the pedal shaft also, but that's minor.)
The forces of the pressure plate's springs are irresistible. That's why people put car jacks on them underheath truck bumpers to release them, or buy hydraulic presses from Harbor Freight.
That rubber bellows has a spring inside it but it's really weak and there's no way it could stop or slow the return force of the pressure plate. It's meant to keep the bellows extended and covering the nose of the slave cylinder between the slave body and the throwout bearing, even as the exposed part gets longer when you have the clutch pedal pushed down. But Saab never used any dust cover in the earlier years of the slave, instead a plastic ring that moved down the piston as the clutch friction surface wore, and could be inspected and used to judge when you might need a new clutch. The sleeve or piston was exposed, inside the bell housing, but it remained clean and free of fouling and nobody ever blamed dirt for wearing out the clutch slave o-rings too soon.
So, bellows torn, or not, it's not something to worry about.
Maybe you have a pressure plate problem? Is that a good brand made in an industrialized land not known for taking shortcuts?
Or, things have gotten into the pressure plate area before and fouled them up - - pieces of the little anti-chatter springs that are part of the clutch disk, for instance.
posted by 71.241.221...
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