Centerforce Duel Friction Clutch
The OEM clutch assist spring helps offset the high pressure needed to open a Borg and Beck clutch assembly. If you disconnect the linkage bar to the Z bar, and push the clutch pedal in, after it goes down a ways (1/3, 1/2 ? can't quite remember), it will all of a sudden slam to the floor. Then you have to manually pull it back up. That's the assist spring in action. A diaphragm clutch doesn't require nearly so much pressure to disengage, to the OEM assist spring is much stronger than it needs to be. So the pedal either won't come back up on its own, or it won't come up smoothly.
If you remove the OEM assist spring, then you have no assist. The diaphragm clutch may be easier to disengage than an unassisted Borg and Beck, but it may be a bit higher than you're fully comfortable with. Such was my case. The lighter spring gave it just enough assist to make for a light pedal that would readily come back on its own.
One thing to remember is that a diaphragm clutch does not require nearly so much plate departure as a Borg and Beck. My memory is that B&B is .080-.090, whereas the diaphragm is .030-.035. Too much plate departure on a diaphragm clutch can make it hang open or even cause the release fingers to hit the clutch plate. Instead of adjusting a diaphragm clutch for OEM clutch pedal free travel, I remove the clutch cover, push the pedal to the floor (either with someone to help or using a two by four), then measuring plate departure with a feeler gauge. That leaves the clutch pedal kinda low when your foot is off of it, so I screwed a block of wood to the floor beneath the carpet to limit pedal travel, which puts the pedal more or less in its factory position when not being used. You may or may not want to do this. Some like a lower pedal.
To possibly help you visualize the lighter assist spring I've installed on mine, here's a pic. As I said above, I don't know its original application, but it was the right length and provided just the right amount of assist.
The OEM clutch assist spring helps offset the high pressure needed to open a Borg and Beck clutch assembly. If you disconnect the linkage bar to the Z bar, and push the clutch pedal in, after it goes down a ways (1/3, 1/2 ? can't quite remember), it will all of a sudden slam to the floor. Then you have to manually pull it back up. That's the assist spring in action. A diaphragm clutch doesn't require nearly so much pressure to disengage, to the OEM assist spring is much stronger than it needs to be. So the pedal either won't come back up on its own, or it won't come up smoothly.
If you remove the OEM assist spring, then you have no assist. The diaphragm clutch may be easier to disengage than an unassisted Borg and Beck, but it may be a bit higher than you're fully comfortable with. Such was my case. The lighter spring gave it just enough assist to make for a light pedal that would readily come back on its own.
One thing to remember is that a diaphragm clutch does not require nearly so much plate departure as a Borg and Beck. My memory is that B&B is .080-.090, whereas the diaphragm is .030-.035. Too much plate departure on a diaphragm clutch can make it hang open or even cause the release fingers to hit the clutch plate. Instead of adjusting a diaphragm clutch for OEM clutch pedal free travel, I remove the clutch cover, push the pedal to the floor (either with someone to help or using a two by four), then measuring plate departure with a feeler gauge. That leaves the clutch pedal kinda low when your foot is off of it, so I screwed a block of wood to the floor beneath the carpet to limit pedal travel, which puts the pedal more or less in its factory position when not being used. You may or may not want to do this. Some like a lower pedal.
To possibly help you visualize the lighter assist spring I've installed on mine, here's a pic. As I said above, I don't know its original application, but it was the right length and provided just the right amount of assist.
