For anyone changing a waterpump on a 1.2. Haynes has a very vague section on this with four spanners (this is not four spanner difficulty). Here is how I did it:
I got an OEM pump from SEAT for £27 (inc. VAT), they take your old one so remove it when picking up the new pump or you'll have to leave a £30 deposit. I thought this better than buying the Circoli pump from Euro Car Parts for just a few quid less.
It's best to jack up the front offside and remove the undertray and offside wheel-arch liner (and offside wheel) for access. Both come off OK, the wheel-arch liner has a couple of screws under the bumper which are not immediately obvious. You should also take off the airbox / engine cover too (I put some cling-film over the now naked engine air-intake).
Drain the coolant.
Loosen off (but don't remove) the three allen head bolts (?mm) on the water pump pulley. You may need to press down on the serpentine belt to stop the pulley rotating, they're not on 'that' tight. There is only one pulley with three allen key bolts, it is the top-left one if you look at the side of the engine from the offside.
Now make a little diagram showing how that belt goes around all the pulleys
Pop off the black plastic cover on the tensioner (there is only one pulley with a cover), put your hand over it as it flys off.
Take a T50 Torx bit and pop it on a longish socket handle. Put it in the bolt in the centre of the tensioner and turn anti-clockwise slowly, this will move the tensioner left (as you look at it). You can then slip the belt off of one of the pulleys. Ease the tensioner back, pop off the socket and pull off the belt.
Belts are cheap (I think my Continental one was £3.90), you might want to consider chucking the belt you just took off and putting a new one on.
Undo the three pulley bolts you loosened before and take off the pulley wheel.
The water pump is attached with four 6mm allen bolts. An allen key isn't going to cut the mustard, a 6mm allen key bit and a socket handle (with a small extension for a couple of the bolts) are better. Looking at the pump from the side of the engine, the top-left one is easy, the bottom-right is not too bad. For the other two, I poked my head under the car and put in the driver and then attached the socket handle from above to undo them. This is because you can't see them from above, but they are easier to undo from there.
Once all four bolts are out, you'll need to give the water pump a good pull to pop it out - you'll get a nice refreshing pouring of coolant too.
I'm assuming refitting will be the reverse of removal, I'll post when that is done later on in the week.
I'll also upload a diagram of the serpentine belt routing and some pics when I put the new one in.
