Pedal set improvements- Now available in limited quantity., Clutch pedal shaft with ball bearing vs bushing |
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Pedal set improvements- Now available in limited quantity., Clutch pedal shaft with ball bearing vs bushing |
bdstone914 |
Aug 27 2017, 10:11 PM
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#1
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bdstone914 Group: Members Posts: 4,537 Joined: 8-November 03 From: Riverside CA Member No.: 1,319 |
Out of the couple hundred pedal set I have rebuilt it is obvious the smallest bushings were out the most. The one in the clutch arm often wears completely through an starts wearing the arm itself. This happens with both the plastic and bronze bushings. It is a bigger problem on later 911's as they use a longer arms and have stringer pressure plates that accelerates the wear. And for some 911 the clutch shaft is NLA. Thank you Porsche.
I have made a prototype arm that uses a ball bearing to replace the bushing. I have now found a 17mm x 6mm x 6mm skate board bearing that will work. I have measured the pressure to depress the clutch and calculated the pressure on the bearing is about 25-50 lbs. The bearing are rated for over 500 lb so it should never fail. I have also toyed with the idea of replacing the clevis pin with a pull type spring loaded ball stainless steel pin. The clevis pins are hard to remove when they wear and there is little to grip to pull them out. The plan is to make new clutch shaft out of a heat treatable steel with the ball bearing design. Considering stainless for the shaft as the pedal sets often rust badly internally. The arm portion would be made straight eliminating the dog leg to the arm. A Delrin spacer that is used on 911's would be used to on the shaft to take up the distance of the offset of the original part. The distance C-C from the shaft to the bearing center could be changed to application with stiffer clutches ( like V8's ) Porsche varied this dimension starting with the SWB cars and made them longer up through the SC's. A shorter arm would give more clutch pedal modulation. I used to weld up the elongated worn hole and reshape ti round. PITA. The the cost for a new arm with a bearing looks to be in the $20 range. Attached thumbnail(s) |
mepstein |
Aug 28 2017, 09:27 AM
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#2
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914-6 GT in waiting Group: Members Posts: 19,315 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region |
Bruce, as soon as you make some, I'm a buyer. Thanks!
I'll also buy one with the longer clutch lever for my 915 conversion. |
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