671 Raw Water Pump Impeller Change, Pump Removal, et al

[Vincentc]

_ Or what I did and what I shouldn't have done

What started as a 30 minute impeller change a week ago is now almost complete.

I have an impeller puller, you just remove 6 screws, take off the face plate, pull the impeller then slide in a new one.

However Lilly Marie is 32 years old, and 2 of the 6 brass screws broke, requiring pulling the pump in order to drill out the broken screws. Access is a bit tight in that area of ER just above the gears.




To remove the pump you have to remove the intake and exhaust elbows. On removal I discovered that 1 1/2" hose was had blisters inside the hose and needed replacement. Nothing that a trip to the parts store won't take care of; however, one new undertaking leads to another. ( more on that later)

As noted in another post removing the pump appears simple, unscrew three bolts; however getting to those bolts is not so simple. I have since realized that a 1/2" short socket can be persuaded to fit in there and you can use a flexible drive to put some torque to the socket.

 

[Vincentc]

With the pump off



I decided drilling out the broken screws was within my skill set. (Not) A drill press allowed me to drill holes into the center of the broken screws. I screwed in the EZ out, applied moderate pressure, but no movement. More pressure only broke the tool leaving a hardened steel shaft in the center of the soft brass machine screws. I was wise enough to stop and go to bed. A trip to a machine shop and $35 got the screws removed and properly located and threaded new bolt holes.

Inspecting the two brass elbows I removed from the top of the pump inspired me to remove the brass cap for the pencil zinc so I could clean up the remains of the old zinc. It was a little stiff but came unscrewed; bad news, the brass zinc cap came out without threads, and I did not have a replacement.

 

[Vincentc]

You may be able to see that the middle hole has no threads.




Not much chance of finding new pencil zinc or a brass bolt on a Saturday afternoon, I found a nylon bolt and nut and some liquid gasket and filled the hole. I should not be a big problem to drill that out and replace with a new zinc at a later date.

The pump says Detroit on the front, but Jabsco on the side. I believe that the number stamped on the face plate is a Jabsco number.




I wanted to replace all of the face plate screws, but could not find them locally. On Tuesday I telephoned Depco looking for replacement machine screws (#10 /32 ) and they shipped me 12 that day and they arrived Thursday afternoon. Almost $3 per screw seemed a bit high, but I respect the issue of dissimilar metals.

Lessons learned/re learned. Seldom are simple maintenance items simple. Respect your limitations and be careful choosing what to do and what to hire someone like a machinist to do in the first place. Don't remove things like pencil zinc unless you have a real need to do so.

 

[Boatsb]

Get a spare plug for every pencil zinc. In the event one leaks or like you just found is not reusable you'll be prepared.

 

[Boatsb]

By the way did you try to find a brass plug to put in in the mean time?

 

[Vincentc]

I had some 1/4 nylon bolts and nuts and used that with a little gasket compound to close the hole. The pump is back together and works fine. As soon as I have time to go buy some pencil zincs I will drill and tap the hole and install a proper plug an zinc.

 

[MikeP]

"More pressure only broke the tool leaving a hardened steel shaft in the center of the soft brass machine screws. "

My experience over many years is that THAT is the result more often than not with easy-outs. Why they are called that, I have never figured out.

I'm surprised the screws were not available locally - our True Value up the street has them.

I wouldn't put zincs in the water pump but other folks have a different view. Our 53 has not had them there at least since the early 1990's; I can't speak for earlier than that.

 

[REBrueckner]

For those pump plate screws, you can poke each one in some grease before inserting to ease them out next impeller chnage. Or an antiseize lubricant of your choice. I changed out the brass for stainless hex head bolts which I got at a local hardware store. Corrosion is not an issue as they don't directly contact water. Easier to get a firm socket grip than a slot and screwdriver.

 

[Finalee]

On the other side you may want to consider changing the ceramic seal too. That is if you remove the pump.

 

[kelpy]

Rather than applying grease to fastener threads, use Lanocote or Tuff-Gel. They will not oxidize over time.

 

[Salty Dame]

Easy outs are usually neither easy nor out.

 

[Andy B]

Ive only had one instance where an easy out actually worked.

 

[Finalee]

Best easy out I ever had was the one I put back on the hook at the hardware store. After spending 20 years in the auto industry I learned they do not work most of the time.

 

[Vincentc]

One more lesson learned. I spent $40 plus to purchase and have shipped to me 12 new, authentic Jabsco brass machine screws to replace all screws for both pumps When I attempted to remove the pump plate in the stbd engine I found it had ss hex head screws. All six came out without problem and showed no evidence of harming the brass pump housing.