Replacing alternator drive belt.

pissativlypossed said:
Hi,
I managed to fit the new belt today, by taking of the water pump pulley (it's held on by four bolts) and Also slackening the adjustment nuts on the alternator it's still a tight fit but it did go on. The new belt is the same part number as the old one and exactly the same diameter, the older one has worn slightly thinner and the vanes (?) have worn down being the only difference.
Incidentally, the old belt came off, and goes back on without taking the pulley off so I will keep it as a spare in case it has to be changed at sea in an emergency, I wouldn't want to have to remove the pulley in an emergency situation.
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Only just spotted this thread. Yes, as you have now discovered, the water pump pulley splits when you remove the 4 set screws. I remove the fan belt for winter storage and find that it will slip back on again (just) in spring. However, new Yanmar supplied belts are usually too tight to fit over the pulleys. I seem to remember getting the last one on without splitting the pulley. I think that there was just enough length with the lower bolt loosened right off and partially withdrawn.

Belt tension on my Yanmar 4JH4AE seems to require very little or no adjustment during the season and only a small amount of black dust collects inside the cover so the compartment remains clean.
 
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macd said:
...a bit like feeding a bike tyre onto a rim (which isn't to suggest you use tyre levers, which of course you're not advocating :rolleyes:) I'd say this is legitimate, with care: belts are not designed to accept forces in this direction.
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When I was younger and used a bike rather more than I now do, it was considered a point of principle to get tyres on and off the rim without using tyre levers!
 
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