Hi Dan, thanks for your info. Mine had no loctite at all and a rather poor arrangement of shake proof washer on top of a plain washer but the problem comes from poor fitting of the splines which were fitted to the flanks but neither major nor minor diameters. This is fine if both items are hardened but not so good with the soft Centa hub. My crank shaft survived the mess and I replaced the Centa hub with a harder and tougher unit fitted on flanks and major / minor diameters. All is well now, I am just wondering if this is a common problem.
Your comments on cleaning of the old loctite are good - more people should be aware of this.
Thanks again,
Phil