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post #31 of Old 12-27-2012 Thread Starter
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Perkins 4.108M DIY Rebuild -- A Narrative

A little more background on this engine.

Based on the engine serial number, this engine began its life in 1987. Our Vagabond 39 is an '85, so chances are better than good that this was a replacement engine installed at some point. Since its also got a couple of layers of blue paint, I'm also guessing that it's been rebuilt at some point along the way as well.

We've run this engine a fair amount since we bought the boat in 2008. We completed America's Great Loop, with many, many hours of engine only propulsion.

Because of a persistent oil consumption issue, as well as suffering from typical Perkins leakiness, I decided to pull it out of the boat and give it a look see. Based on my observations during tear-down, I consider it absolutely worth keeping.

So, now the story can proceed... Comments, suggestions, and humorous additions are more than welcome


Chapter 4: The Water Pump (a Postmortem Report.)

Well, I knew that my good luck was destined to run out at some point...

I had a suspicion that my water pump was overdue for attention, and since I'm taking everything else apart I decided to tear it down as well.

As you can see, it was a dirty mess. That said (and even though the rust/corrosion on the case was humming a different song at me) I didn't think that it was failing. I've never noticed any drainage from the weep hole, never seen any coolant in the bilge, and I've never had to add lots of coolant in the header tank since it's always remained at a trusty, visible level.

The disassembly began with removal of the pulley, which is a hell of a lot easier said than done. These puppies are pressed onto the shaft, and without a spline or key they rely solely on friction. As you might guess, the force required to get the pulley on is substantial -- here's what the manual says concerning replacement:

You may also surmise (and you'd be right) that removing it ain't easy either.

After I chased out the threaded holes in the pulley, I set up a harmonic puller:

I worked my way up though the applied force arsenal: combo wrench, combo wrench with a cheater bar, big honking adjustable wrench, Milwaukee impact driver -- no joy whatsoever. I was getting concerned...

I then broke out the heaviest gun I've got:


Drove out the bearings...

After a mineral spirits bath...

Then things started to take an ugly turn.

The seals are shot, and were probably already leaking. The shaft also looks overdue for replacement. After consulting the service manual, I also am pretty sure that there's supposed to be another seal assembly between the bearings and the impeller cavity -- missing parts are usually not a good thing.

The Perkins parts manual lists a repair kit that includes the seals, shaft, and impeller, but that part number yields no returns in web searches. Parts number searches for the seals themselves also came up empty. Transatlantic Diesels advised to just go with a replacement pump, since they can't get the repair kits either.

I cleaned and prepped the pulley for paint -- if I do have to buy a new pump, I'll still have to use the original pulley.


Last edited by Faster; 12-28-2012 at 02:24 PM. Reason: cleaned up post-merge
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