Fixing washing machine leaks
Given time, all washing machines leak. If the leak appears on the floor, creeping out from under the front of the machine, the likelihood is that it is the door seal that needs replacing. If the puddle seems to be emerging from the back of the machine, it's probably the pump. Pump leaks tend to be small and you only usually find them when you happen to pull the washing machine out of its cosy hole under the worktop.
Door Seals
Have a good look all around the inside of the door seal. The hole can be quite unobtrusive and need not be at the bottom of the seal. If you find a hole then pop along to your friendly neighbourhood washing machine parts supplier with your full washing machine name and model number and get a replacement.
Pull your washing machine out of the dusty hole where it usually resides and unplug it. Open the door and pull the edge of the door seal off the lip round the door on the front of the cabinet. Fingernails usually suffice for this. Having done this, insert your fingers through the gap outside the door seal and have a feel around the edge of the drum where the inner edge of the door seal is attached. If your machine is anything like mine then you will feel a slim metal "jubilee clip" type retaining wire holding the door seal tightly to the drum. Remove the top of your washing machine. This will expose lots of wires and switches all at mains voltages. If you haven't already done so, make sure that your machine really is unplugged. Look down the front and see if you can spot the clip holding the door seal. It's usually quite a long way down and relatively inaccessible so a long screwdriver or 1/4 inch drive socket set with extension is required. Slacken the screw/bolt and then simply pull the door seal off the drum.
The new door seal will look like a floppy tube with no apparent correct orientation. Look carefully around the rim that attaches to the drum and you may find an edge with holes in it. This point should be lowermost, as it is there to allow water in the bottom of the door seal to drain back into the drum. If you fit it the wrong way up, your new door seal will fail prematurely.
Now comes the tricky part. Take the retaining clip and fit it loosely to the inner door seal lip. Make sure that the retaining clip screw is orientated in such a direction that you will be able to tighten it from above. Wiggle the door seal onto the lip on the drum, making sure that the holes (if any), are at the bottom. When you think you've got it on fully, go to the top of the machine and tighten the clip. Now you can stretch the outer lip of the door seal over the lip around the door on the cabinet, making sure that there is no axial twist in the seal making it wrinkled. Wrinkled seals die young. If you can't seem to get rid of a wrinkle then this means that there is a slight misalignment twixt drum and door. A common cause of this is breakage or detachment of one of the springs that hold the drum centred. They can be a bugger to reattach but it's worth doing as misalignment is another cause of early door seal death.
Put the top back on and congratulate yourself on a job well done.
If anyone has come across a door seal fitting that differs enormously from this plan, feel free to amend it.
Pump Leaks
The pump on your washing machine is an uncomplaining little thing, and rarely gives rise to serious problems. With age however, the seal around the motor shaft can start to leak and the only remedy (as far as I'm aware) is pump replacement.
Unplug you machine, whip the back off and have a good look with a torch if necessary to see if there are tell tale signs of water leaking past the pump shaft seal. (If you're not familiar with these things, the pump is the small motor near the bottom of the machine with a small fan attached to one end of it and a pump chamber with two hoses attached to the other.) If it is leaking, take your washing machine name and model number around your local parts supplier. There's a good chance that they'll have to order it so you might prefer to do this bit by phone.
When you get your pump, don't be too surprised if it doesn't look the same as the old one. Many of the metal components will probably have been replaced with plastic ones, but as long as the mounting screw holes and hose positions are the same, don't worry about it. Removal of the old pump and replacement with the new is usually very straightforward.
Machine won't spin, empty, or overflows
A very common cause of these problems is blockage of the line to the water level switch. Near the bottom of the drum is a connection to a small tube which rises to well above water level, where it is connected to the switch. As the water level rises, the pressure of the air in the tube increases, and compresses a diaphragm inside the pressure switch, causing two or three sets of contacts to change over at different water levels. It is very common, especially in hard water areas and when the hottest wash is not used, for limescale-based gunge to block this tube and prevent the air pressure switch from operating at all, or operating quickly enough. This may make the machine think that it is empty when it is full (and will thus overfill), or full when it is empty (and will thus refuse to spin).
On Hoover and possibly other machines, the connection to the drum is via a small plastic bottle, which often gets full of gunge. It seems to me that this bottle is either to damp the pressure switch (preventing it changing over as the washing sloshes about) or to allow more gunge to collect before it is rendered inoperative.
Pressure switches are easy to test: they are sensitive enough to operate by blowing into them, whereupon you should clearly hear the click of the contacts. With all the wires disconnected, an ohm meter can be used to check the electrical integrity of the switches - a bit of experimentation should establish which contact is which of the changeover mechanisms.