re MTD: the creator / original owner of MTD no longer had the time necessary to keep up with the site. As a result, he sold the site to a forum conglomerate, VerticalScope ("with over 800 forum communities"). They migrated the site from its old forum software to their preferred platform, and in the process a lot of content was temporarily mislocated and/or its formatting overhauled (underhauled?).
As mentioned, much of the site's wiki has been 'restored' (see above link), but it is no longer presented in an organized or coherent fashion. Major pity.
Thanks for the advice re the a4timingbelt.pdf mistakes.