DMF about to become
Join Date: Mar 2015
Location: United Kingdom
Sounds a bit like either the pressure plate is not torqued up fully so it's oscillating and letting the release bearing pop out, or if it's still got a dual mass flywheel, it's worn and oscillating giving the same effect. If either, you may be able to detect a rattle, when hot, from the bell housing, with the clutch engaged
If it's the spring/clip on the release bearing I can see how it would cause the judder. It can't be half located really. It's either behind the pressure plate fingers or it's not. The judder can only be axial movement in pressure plate or flywheel, or radial movement in fiction plate hub. If the latter, the release bearing wouldn't come out. Be interested to know when you take it apart again please!
I fitted a Borg and beck clutch and it lasted about 1100 miles before the rivets that hold the friction plate to the outer material ring sheared off. The valeo I put on after has been fine for 10k now.