Yanmar 1GM water pump

[pagoda]

We have just had this same issues, but with a bit of northen engineering it works.

the nut is a 10mm so if you get a 9mm socket and extension and hammer this onto the corroded head (use alot of force) it dislodges the rust and frees the bolt then with alot of force into the thread (not torque) it shoudl pop off,
the others came off using some nedle nosed molegrips.

after a few hours swearing ours came loose this way

Done that method a few times. Especially useful if there is a thin skin of even rust on a bolt head = 1 or 2 sizes below normal.
It gets very scary doing this on anything under 6mm. They tend to behave like Cheddar cheese ...

 

[RichardS]

Done that method a few times. Especially useful if there is a thin skin of even rust on a bolt head = 1 or 2 sizes below normal.
It gets very scary doing this on anything under 6mm. They tend to behave like Cheddar cheese ...

I was undoing four 8mm bolts on a car yesterday .... 13mm heads so quite chunky but the bolts protruded a cm beyond the captive nut. Two of them were badly rusted on the inaccessible thread beyond the captive nut, so after treating with easing oil I gently undid them a 1/4 turn, then back in, then out 1/2 turn, them back in etc etc.

The first one came out after a few minutes but after half a dozen threads the second one went tight on the anti-clockwise turn so I turned it clockwise as before but this time it was rock solid in both directions, even though it was now well out beyond the outer plate. Not being able to budge it in either direction resulted in the inevitable shear once I applied enough (too much!) force. Then followed the inevitable drilling out and re-tapping.

That's the first time I can really remember a half-removed bolt shearing.

Richard

 

[Wandering Star]

Sorry for reincarnating an almost 4 year old thread but it does save everyone having to repeat their advice and experiences for my benefit!

I have a leaking water pump on my Yanmar1GM10. The boat came to me with a brand new boxed Yanmar water pump So instead of stripping the old shaft £ replacing the seals & bearing, I thought it would be a 3 minute job to just replace the entire pump with the new one.

Half a day later I’ve managed to remove 2 of the 3 bolts by hammering a 9mm ring spanner over the bolt heads. The third bolt also refuses to budge but is so inaccessible behind the belt pulley, that I can’t get the spaner on and I can’t use the hammer method. So my question is, how do I remove thi third bolt? I’m loathe to remove the belt pulley (I’m not naturally mechanically minded) but I will if it’s my only option - if I do, is it relatively simple? Is there another simpler “trick of the trade” to remove the bolt? The 2 bolts already removed turned out to be reasonably solid and I suspect this third one will be too.

Any ideas from the usual suspects or others?