Thanks a million guys for all the advice. A great response, proves what a great message board this is. Now I feel a bit of a twit using the WD40, I should have known better. But in my defence thats all I have at the moment. I will try and get a proper penetrating fluid tomorrow. One thing I have noticed though. I can see evidence of a hard gunky substance around the hole in the housing and around the broken off piece of bolt. There is no evidence on the other bolt. I wonder in the past was some kind of locking fluid or similar used as it wasnt tightening properly. I suppose its irrelevant now, except it might make the rest of it really hard to get out. I think I will use the penetrating fluid and leave it soak for a few hours. Then I might heat the surrounding area gently and then try the punch method. If that fails I can always bore out and tap a bigger bolt. Or how about these helicoil things? I know nothing about them, are they worth it, or any good? In the meantime I am forging ahead with the rest of the work. I got the old water pump off last night (early this morning really
) and what a state it was in. No wonder it was noisy, the impeller was actually rubbing off the inside of the housing! such was the amount of play in it
A good clean down of the surrounding area of the build up of oily gunk and so on was called for and I gave the rad, expansion bottle and engine block a good flush out with the hose. One thing I did notice though which I found a bit worrying; the bolts holding on the old pump were quite difficult to unscrew, and when I got them out the threads on each bolt were full with a dusty rusty substance as if they were rusted in. Should I try and clean out the bolt holes?