Raw water pump, weep hole weeping and almost a rebuild..

Some time ago I noticed that the raw water pump in our port engine developed a leak, not much but enough so that I could see the water dripping from the weep holes just behind the impeller housing. I could have used the boat but the idea of saltwater dripping to the belts and spraying around the engine room was too much for me. So a repair was due.

TAMD 40B raw water pump. The water was dripping from the weep hole just behind the impeller housing.

This is what we started with. It was an easy task to get the piping and hoses off from the pump after I shut the sea cock and used a hand pump to empty the sea strainer and the pumps feed hose (I didn't want to get any water to the bilge). After the hoses were out the pump is attached with two bolts, be careful not to loose the key that connects the pumps axle to the gears in the engine. I dropped mine to the bilge but managed to fish it out with a "grabber".

After I had read the great article Rebuilding A Raw Water Pump by Compass marine, I decided that this is a job I can pull through myself without getting Volvo mechanics involved. I followed the instructions in the article and although the build of the pump is different than in the article the same principles apply. 

After tapping the axle and the bearings away from the housing, this is what I got. By looking at the bearings I noticed some rust on the pump side of the first bearing and some wear marks also in the shaft. So when the boat gets out of water I will do full rebuilds to both pumps (bearings, shaft and seals). At least I have something to tinker with in those long winter nights. 

Internal parts

At this phase I realized that there are few types of pumps used in these engines and naturally I have the ones with the most expensive parts, at least when looking at the prices from the local Volvo dealer. Well, anyway the process had begun so I needed to remove the water seal.

Source of leak, nearly totally worn lip seal. 

The water seal is best seen after removing the insert and the wear plate, the screw for the insert was tight as hell but broke loose with a good screwdriver and fury.

Broken lip seal seen from the bearing end of the pump. 

The seal itself just popped out of its place with minimum force and once I saw what remained of it it was clear that this was the source. It had lost its "lip" and there were some sand particles lodged between the rubber and and the seals metal base.

Original lip seal, or whats left of it anyway. 

As this was one of my kitchen table projects I needed to use the tools that I had handy. It would be better to this in a shop but while not having such luxury it can be done neatly in domestic settings.

New seal and some precision instruments. 

After looking for a new seal I found a place where I could get one with reasonable costs. 8 euros versus 50 something what I would have paid for at the dealer, plus the waiting time of at least four days. It really is a standard lip seal with 25x52x7 dimensions. I also got the stainless springs to replace the ones that were in place in the new seal. Changing the springs was something that even my daughters would know how to do.

Axle in and rest of the parts still remaining. 

When pressing in the axle and the bearings I put the shaft and the bearings to the freezer for a few hours in order to shrink them ever so slightly, maybe they shrunk a bit since it was easy to tap them into the housing, certainly easier than getting them out.

In hindsight, it would have been easier to press the new sealing in before the axle and bearings so I would have had better access to the seal without the axle being in the way. Anyway it worked like a charm like this as well but no I know how to do it for future references.

Insert the wear plate

After the seal was in place it was just a matter of putting it all together. After inserting the wear plate I put some silicone sealant to the bottom of the cam and to the cam screw in order to minimize chances of leaking from the screw hole. 

If you look closely I had the odd side job of gluing the diamonds back to the kids tiara. I think this was the second time around, so I think that I need to use epoxy if they fail again.

Just insert the circle clip and its nearly done.

After the pump was put back together I put in the impeller, making sure I used enough of glycerin based hand creme (nicked from the wife), in order to avoid any dry running. I intentionally left the cover plate off because as you see above the axle slot and the key (in the engine) need to align and you need to align them while installing the pump. 

It is much easier to use a good size screwdriver to align them while the coverplate is off. Another good reason for leaving it off is the fact that in Volvo's world the cover plate screws also double as clamps for the retainers (see the very first pic) and you need to attach them while the pump is in and all the hoses are attached and secured. 

After installing the pump and priming the sea strainer (filling it and the hoses with water) it was time to run the engine (with the sea cock opened). Sadly  I noticed that the top pipe (pump to engine) leaked. The fix was simple, it just needed to be pressed harder into the pump housing by using some force. Somehow I did not get the pipe and the o-ring pressed deep enough the first time around even though the retainer was in perfect position. After some adjustments there were no leaks anymore. 

The next day we took the boat out and I was watching the temp gauge every few seconds to see if all was well. The temperature rose in perfect harmony with the other engine and at cruise speeds it stayed at 80 Celsius, just where it is supposed to be. So, job done for now but when the winter kicks in I will rebuild both pumps and make sure that I don't need to worry about them for the next ten years.