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> Pressure Plate Fasteners Question, What size & grade?
frank_c
post Jan 31 2026, 12:21 AM
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I just had my flywheel lightened, and I'm having it and the pressure plate balanced next. I want to include a new set of the six bolts and washers that clamp the pressure plate to the flywheel before giving the parts to the machine shop. I thought this would be easy (IMG:style_emoticons/default/sad.gif), but here's what I found:
  • PET states that the bolts (900-075-104-01) are M8x15 (NLA)
  • Searches show both 8x16 & 8x20 are recommended, with 8x20 being more common (the 8x20 bolt does capture all the threads in the flywheel, the 8x16 does not)
  • Some results say Grade 8.8 is fine, other say 10.9 or even 12.9 is necessary
  • Regarding the washer, PET indicates a split-type locking washer, while most search results say to use a wavy lock washer
I know we are only talking a few grams here, but if 8x16 is fine, then I'll go with that instead of 8x20. But what about the hardness? I suppose there is no harm in getting 10.9, but is 12.9 really needed for this application?

And split or wavy on the lock washers?

Btw, the old bolts I removed were 8x20 Grade 8.8 with a wavy washer, but of course that does not mean they were correct.

And one more - Blue Loctite, yes or no? (for final assembly)

Thanks for any help.
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