cerimania wrote:they had a special torque wrench
http://www.halfords.com/advice/cycling/how-to-guides/video-how-to-replace-a-cranksetI don't think much of that Halfords video: torque wrenches should not be used to undo bolts.
The Park Tool video linked below is more comprehensive in explaining what, why and how, and shows you the different types of tool (including versions with and without integral handles), as well as making it clear that a torque wrench is recommended but not essential (and for your bike and chainset, I would quite happily just use a good quality allen key like they show in the video [or equally a ratchet handle with an allen key bit if you've got one]).
Park show grease being used on the axle when fitting the crank, but that is an Octalink splined axle, and I would not use grease on the square taper axle you have. I have never greased the threads of the crank prior to screwing in the crank extractor as suggested in the Halfords video: I have never had a problem screwing the extractor tool into dry threads. Far more important, as the Park video shows, is making sure the extractor tool is
fully engaged in the crank threads, otherwise you risk the steel tool stripping the softer aluminium threads instead of pulling the crank off the axle. As the Park video shows, this means that the bolt part of the tool should be backed off/undone before threading the the tool in the crank, otherwise the bolt may come into contact with the end of the axle before the tool has fully engaged in the crank threads (giving the false impression that the tool is all the way in and fully engaged, when instead the bolt is pressing against the end of the axle).
As for pedal wrench, check your pedals: do they have flats for a spanner where the pedal axle enters the crank? If so, then you need a 15mm spanner. If the flats are wide enough, you may be able to use an ordinary 15mm spanner. A pedal wrench is simply a narrow 15mm spanner with a long handle to give good leverage (and if the pedals' threads were not greased when the bike was originally assembled, you may need more leverage than a short handled spanner will give). If there are no spanner flats, then your pedals will probably need an 8mm allen key (i.e. likely same size key as the crank bolts) - the socket for the allen key will be on the inside end of the pedal's axle.
https://www.parktool.com/blog/repair-help/crank-removal-and-installation-three-piece
I am a beginner on bike maintenance