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Old 05-25-2014, 11:02 PM
Pete Munroe Pete Munroe is offline
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Join Date: Mar 2003
Location: PVE, CA
Cobra Make, Engine: ERA 289 FIA #2027, 65' 289" PS wheels
Posts: 345
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Default check the "shoulder bolt"

After reading your post I am not clear if your problem is play in the splines or if the pedals are loose on the shaft...my car would break the shoulder bolt on the clutch pedal...you could work the clutch pedal fore/aft back and forth as the bolt was only acting to pin the pedal to the shaft after it would break.

I never had a problem with the spline and the bell crank being sloppy, the set screw would loosen occasionally but the problem was the clutch shoulder bolt.

When you push the pedal the rotating load is not taken by the shoulder bolts thick shank...after the play in the hole is taken up the load transfers to the weak threaded section of the bolt...and the bolt snaps at that point.

It doesn't matter how tight the bolt is. The bolt "shoulder" hits the inside of the tube and keeps it from compressing the tube. So the bolt is tight in the sleeve but the tube is not being compressed onto the shaft. When the assembly rotates the tube/sleeve will move until all the play is out of the bolt hole in the shaft. Then the load is transferred to the bolt and it snaps at the threaded section.

After breaking the bolt 3 or 4 times and hating the play in the clutch I ended up drilling out the shaft and tube for a slightly larger bolt...ground off the old nut and welded a larger nut on.

Now the bolt acts to compress the tube and clamp it to the shaft, not act as a "pin"

Used a slightly larger diameter bolt with socket head. No need to use a shoulder bolt now...

Wish I had taken better notes and pictures as I did this several years back. Anyway have not had a problem since. Great to pick up a little more clutch travel as the entire assembly now stays solid.

Hope that made some sense...pictures may help to visualize but a good cross section drawing would make it more clear than I can explain...
Pete
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ERA 289 #2027
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