Post #7 by TrevorJ » Wed Aug 21, 2013 7:17 pm
I'm not familiar with the JCB, but, there are some simple things which will improve the odds of getting the pulley off without damaging it.
You may have done or checked this already, and just simplified your comment above.
If you've cleaned up the front of the pulley surface and spotted some extra holes that appear to be blind, chances are they are threaded and there are 2, 3 or 4 holes spaced around so bolts can turn in and gently force the pulley off. If so, you may be able to push the pulley off by way of screwing, (in an even manner) suitable bolts into threaded holes in the pulley plate. Generally there's not a lot of body where these threads are, so tension accordingly.
If there are threaded holes in the pulley, but nothing they can push against, chances are the pulley is designed to be removed with a plate puller. ( Just guessing yours isn't like that - the diagram doesn't seem it suggest to me it's large enough.
Pulleys can be quite obstinate, especially those which are a tight fit, and there is no threated hole feature to aid removal.
This means using a puller, and two legs may be alright if the pulley isn't too tight, but three legs would be my choice, in most instances. Many smaller pullers legs are just going to pull on the outside of the pulley ... the aim is to get as close to the bottom of the vee that is feasable. (Again, I'm not familiar with JCB to know how much room you've got there.)
Tighten the puller to a level back to the "moderate" pressure you're happy with. The trick with a puller is hitting the top of the puller with a hammer while under tension. The jarring of the shock does wonders to tight things. Something small and fragile like a pulley, just a light tap a number of times, and check then if it has gotten easier to turn, and for deformation just in case. If it's not easier, you can try hitting just a little hard and check again. If it is easier and it hasn't deformed, turn the puller in some more to back to what you're comfortable with. Tap the top of the puller again a few times and check and so on.
Other things which helps - I'd use this only if replacing the water pump. If you've got access to quick heat, like oxy acetylene - ten or so seconds over the front surface with a good flame, and a gentle tap from behind to see if the expanded front surface has given enough to let if come off. In some instances, yours may be one of them, the puller is already placed, exerting some pressure before quickly heating the surface. ( I say ten or so, because again, I just don't know how thick the metal in the pulley is, but mineral oil if placed there immediately afterwards would instantaneously fume and smoke - the metal doesn't need to go anywhere near a dull red glow)
If ther isn't any movement, quickly drip over mineral oil around any exposed joints, ie the collars front and back. Wait to cool, try the puller again. No luck - knowing it really is being difficult, bag the water pump in a clean disposable waterproof bag and place it in the freezer overnight. Other bags work, but there's usually someone around the household who'd have preferred you'd hopped in the freezer as well, to get a first hand experience of the penetrating fumes given off by even fairly clean parts.
Overnight in a freezer or even a couple of hours in a freezer set to very cold, everything shrinks a little, so a quick heat should create a wider clearance between the two parts.
The important thing is heat quickly, and then move straight into trying to see if the pulley has freed up a little, without any delay. Pullers are a bit of an obstacle in the way, does make it a little harder to heat evenly, but is can be worthwhile. The puller shouldn't be quite as tight as you would if it were cold though.
HTH if you haven't tried that already.
no telltale coolant loss or seeping from the telltale hole 
)
