R&D driveplate

Ever wondered what your driveplate looked like and what it does?

This is a brand new R&D driveplate:

Note the part number 12AA70 and direction of rotation at the top – very useful if you want to replace one. The six holes around the periphery bolt to the flywheel, the splined hole in the middle connect to the gearbox.

If you take it to bits, this is what you have:

Top right is the friction damper, bottom right the driven plate with it’s driven pins, bottom left the drive plate with the three drive pins and the plastic spring.

The driven plate has three plastic coated pegs and a splined centre:

The drive plate also has three pins. Finally, the plastic spring connects to the drive pins and the spline on the driven plate

As you can’t see what is going on when everything is together, I’ve substituted a bit of steel rod for a driven pin in the picture above. Under low loads, the plastic spring drives the gearbox around by linking the drive pins to the central spline. Under high loads, the spring deflects enough for the driven pins to touch the spring as shown above. A different part of the plastic spring then comes into play

On the back of the drive plate is this friction damper to stop rattling and nadgering:

It is made from a friction disc sprung against the drive plate with a – er – spring. These parts are from a used plate:

Finally, it’s amazing how much wear these plates can take and still work:

Notice the spring has failed long ago, the plastic sleeve has gone from the driven pins and the driven pins have eaten into the drive pins.

Amazing that it still worked!

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