Cat D318 Water Pump

Main thing is don't pull the whole rear of the pump/thermostat housing etc off the engine, just unbolt the guts of the pump and remove the fan to take it out the front.

I did one on the track of our 9U one day. Bought the seal from CAT and put it in. The seal isn't anything unusual, just a carbon seal riding on a ceramic seat. When they sit for a long time, the carbon ring can stick on the ceramic and when you turn the engine, it may crack the carbon. That will be a big leak usually.

Cat price isn't likely to be too bad unless you compare it to the $10-15 you might pay for a similar seal from a pump or industrial supply house. It won't break you to get it from CAT and it will be the right one the first time.

CC, the earlier impeller was just metal to the seal but in little later years Cat wet to the ceramtic seal surface on the impeller where it rides against the seal.He will have to check and see which his has in it and usually if the impeller is all metal chances are it,s worn beyond using over again.I have rebuilt dozens of them over the years on various engines and the older ones were pretty much the same setup on the impeller and seal assem. back then.Sometimes the impeller can be smoothed up if it isn,t worn too much.It was a good improvement when they went to the impeller with the ceramic seal attached to it for a replacement.

SJ, I got to thinking and I can't remember is the seat is ceramic or polished metal (silicon carbide?). Either way, I know it's hard on them to sit for months sometimes and then start up. Ours that failed that way had shattered the carbon seal ring so it was really leaking fast!

Might be possible to machine the impeller to take a seat if it's worn too bad. Just have to cut it back enough to take care of the thickness of the washer. Looking at the parts book, I don't see any separate seat, they show a
4F4769 seal assembly consisting of-
2H560 bellows assembly (does this include the carbon ring?)
5F9140 washer (seat or carbon ring?, can't tell from the parts book picture)
Impeller is 4F5995

The carbon ring seal seat is the impeller. No fancy seat here.

Hello,

I live on a boat, build in 1903 in the Netherlands. In 1954 a Cat was build in, a D318. Wonderfull machine...

Now the mechanical seal of the cooling water pump is rotten, so I have to replace it. As you all write it's not too hard if you have the right parts, but that's my problem. What parts to get? Any numbers? Where to get it? Any hints on getting the rotten one out, without damaging the rest?

Thanks in advance.

Justus Beth