How stop these fittings from leaking

[hd002e]

Originally Posted by tkeithlu

Oops. It's the pipe fittings, not the cover plate.

1. Disassemble.

2. Inspect the threads (?) holding the tubes into the pump.

3. You may need to replace the tubes, or if you have some slack, extend the threads so you get a longer grip. See Belize Sailor above.

4. If it's ot held by threads, just what holds it. We can start over with a picture of the offending tube loose from the pump.

5. Hang in there. It's frustrating, but fortunately there are only so many ways it can fail, and you are going to find it.


Third look. Are these tubes ended with O-rings and then held in place with that little clip? No wonder it fails. Replace the seals, and for a quick maybe cure, bend the clips so they are tighter. Then it's replace the clip.

The terrible design of these fittings have no threads, no barb, no o ring, they are square section seals as posted by another member above and they are held in place with sheer luck. There is no pressure on them. I will try to get a photo of the pipe tomorrow.

I took the clip out and tried to bend it slightly so that it applies more pressue on the seal but it makes marginal difference at best. I cant believe they would design it this way!

[hd002e]

Originally Posted by sailah

Faced with that situation of an unacceptable sea water leak at the pipes, and if I can understand the situation it is the pipes sticking out of the pump body, and there is no way to get a good seal with the current setup...

I have 2 possible solutions that I would consider.

1: I'd need to determine how the pump is made and wall thickness of the pump tube bores but it looks like you might have enough meat there to simply tap the pump body for NPT threads. Then you simply thread in hose barbs with thread sealant and replace the bronze tubes with hose and hose clamps. This would involve measuring the tube bores with a caliper to see what the diameter is, and if this matches up with common NPT thread drill sizes. If yes, great, if not, you'll need to set up pump on a mill or lathe and bore them out to the correct size before tapping.

Or solution #2...

I'd buy bronze pipe barb nipples with a sufficient thread size to permit machining off the fitting threads with a lathe to a slip fit. So if the diameter of the pump bore for the tube is 20mm, I'd machine to 19.85mm. Clean out the pump after I removed it of course and remove all bearings and seals. Then flux and braze the fittings to the pump body.

Replace the bronze pipes with hose and hose clamps.

This would be a simple task for me since I have a lathe and torch etc but easily done by a machine shop. They might even be able to make the hose barbs since it's just a simple matter of the barbs, you don't need the hex or the threads.

Something like this: https://www.mcmaster.com/9431k13

This is very helpful! Thank you. I have access to a good machine shop and even though I do not have the skills or the equipment to do it myself, I can certainly ask them for help. One question - if I am NPT threading in a fitting like you linked to at mcmaster - does it have to be same material as the pump ie bronze or can it be stainless steel? I may not be able to find fittings in bronze but in stainless. If they need to be bronze, I can ask the machine shop to make them for me.

[Cheechako]

Originally Posted by hd002e

This is very helpful! Thank you. I have access to a good machine shop and even though I do not have the skills or the equipment to do it myself, I can certainly ask them for help. One question - if I am NPT threading in a fitting like you linked to at mcmaster - does it have to be same material as the pump ie bronze or can it be stainless steel? I may not be able to find fittings in bronze but in stainless. If they need to be bronze, I can ask the machine shop to make them for me.

Be very careful the shop knows how expensive those pumps are! They may think it's just a $25 pump. Pipe threads are tapered and like driving a wedge in there. That is cast Brass or bronze, the outward force could very well crack that pump housing. I would not attempt it with less than maybe 3/16" thick wall or more. I would be tempted to try a straight pipe thread maybe if you can find the fittings.

[sailah]

Originally Posted by hd002e

This is very helpful! Thank you. I have access to a good machine shop and even though I do not have the skills or the equipment to do it myself, I can certainly ask them for help. One question - if I am NPT threading in a fitting like you linked to at mcmaster - does it have to be same material as the pump ie bronze or can it be stainless steel? I may not be able to find fittings in bronze but in stainless. If they need to be bronze, I can ask the machine shop to make them for me.

For the simple matter of galvanic difference, I would stick with similar metals. Bronze is pretty close to stainless. The reason I suggested buying a hose barb fitting is that they are readily available. Just machine off the threads if going for a slip fit. But machining a new hose barb is dead simple for a lathe operator. You are talking a few minutes of machine time to make one after you buy the material. Chucking up an existing fitting and knocking off the threads to an OD that will fit your pump is even faster and cheaper if going for a braze fix.

If you are going for a threaded fit by tapping out the existing pump body I don't see why you couldn't use SS but I personally wouldn't as bronze is available.

The comment above about NPT fittings is accurate as they are a tapered thread. The tighter you crank on the fitting the more it forces into the threads. If the wall thickness isn't sufficient then you certainly risk cracking the pump. You don't need a ton of force to get a perfect thread seal. I use Loctite thread sealant and it would work great for this. https://www.mcmaster.com/45855k81

They do make straight threaded fittings called NPS but the taps are expensive etc.

It's one of those things where I'd need to hold it and measure, see how it's made, how much wall thickness I have etc. before making a decision about how I would fix it.

[sailah]

If you are in the US, in Cape Cod, there is an excellent machine shop I have used called Turn Wright Machineworks. Keith Fenner has all the skills and tools to do exactly what I outlined. I used him to weld a boom back together during a race as well as a number of other things. His primary business is marine shafting. He has some pretty cool YouTube videos about marine specialties to get a sense of how he tackles projects.

This would be a simple one I think.

https://turnwrightmachineworks.com/

[jmschmidt]

I had a similar problem with my Vetus-Mitsubishi. It used a shaft driven off of the engine's power takeoff upon which Vetus mounted both the mechanical fuel and raw water pumps. The tiny O rings on the shaft isolating this lash-up from leaking water regularly failed. Raw water first destroyed the both pumps and then let seawater trickle into the crank case through the power takeoff port.

I ripped the whole thing out and tossed it. Had a machinist make a second pully for the crank shaft. Fashioned an L-shaped bracket to mount a Jabsco belt-driven raw water pump, install a couple of Volkswagen electric fuel pumps ($15) and its worked fine for the last 25+ years. Newer electric pumps ($50) supposedly designed for diesel are available to replace the VW ones (which need replacing every 10 years or so) but can't say they are $35 better.

Don't know if you have enough room to do installation this but you might consider it.

Leave it to the Europeans to attempt to marine-ize a fine little Japanese engine and turn it into a mess.

[Paul L]

Originally Posted by hd002e

The wire clip is to gently aid the pipes into the pump, not enough to keep them sealed.

I hesitated to get new seals this time around because with the heat exchanger I got a set of seals for each fitting and they were so badly leaking that I figured it would not make that much of a difference here either.

On the heat exchanger. There is a slot at the rear mount. You need to loosen the bolt in the slot and slide the heat exchanger,. Setup all the pipes and new seals, then slide together and tighten.

It is possible to get these to not leak, but it is a nightmare design.

[Compass790]

It's obviously a crap design. I'd go for a rebuild as sailah suggests & get rid of the inherent design faults. You could epoxy machined to slip fit hose barb fittings in the raw water pump no worries if you don't have brazing access.
Rubber hoses last for a long time

[BlackHeron]

Clean the pipe and the socket methodically. Like a surgeon washes his hands and tools. Polished cooper pipe, like new socket.

Use new rubber seals every single time unless you just took it apart after a failed attempt to fix something or one of the many seals in the assembly leaked. If so then start over prepping for open-heart surgery by cleaning again.

Never ever bend or force the pipe. If bent, tweaked, or disfigured it'll never seal again. Treat these pipes like diesel fuel pipes. They go together in a specific order like a puzzle. Never force them. This is very important when you remove the heat exchanger or freshwater pump.

Put the rubber seal on the tube first, then install into the socket, not the other way around. The sharp tube may well make a micro-cut into the seal if you try to insert it into the seal already in the socket.

Lately I have been cheating and "wetting" the cleaned pipe and socket with a molecule-thin coat of Teflon pipe dope. Not enough to get into the coolant and cause issues to the water pump or T-stat. Just enough to lube it to help seal it and ensure even spring-rubber pressure around the whole seal. Probably not kosher according to Calder but it works really well. Have yet to have one leak with the Teflon dope in there This technique also works really well for leaking water tubing on recalcetrant hose barbs that refuse to stop dripping no matter how tight you make the hose clamps.

Volvo-Penta sucks. This is really, REALLY bad engineering. Buy a Beta.

[BlackHeron]

For those saying to somehow braze or machine hose barb fittings into this pump please notice there is barely enough room for the crankshaft pully and belt to pass this tiny copper pipe as it is. In fact, if the pipe is not put in just right (twisted slightly) it will physically rub on the pulley and can burn through the copper pipe. It is even tighter on the turbo version as the water pump was up-sized. If you even look at that pipe funny it will rub on the pulley

Volvo-Penta design...

[jimbunyard]

Fought those elegant but useless things for years, the only way to guarantee they won't leak, usually sooner than later, is to replace them.

I replaced them wherever I could on my TAMD41B, using the most appropriate method in each individual case; tap and hose barbs for the raw water pump, pieces of the infernal copper pipe and solder for the aftercooler and raw water inlets on the heat exchanger. Put a little dab of solder or two on the hose end of the pipe for hose retention.

Follow the suggestions above about metal selection and tightening/sealant. The wall on my pump was a little thin, and there may be a recess on yours for the oring that thins it even more in what seems a key place. If push comes to shove, thread it and use one of the miracle metal epoxies to glue the sucker in permanently. Bronze fittings are readily available.

As for not enough room, in this case an inch really is as good as a mile; from your picture it looks like you have plenty of room, if you're worried you can always zip tie some metal shields around the hose in the appropriate places.

If you can find a decent supplier, silicone hose makes things a lot easier and lasts a lot longer.

It is worthy to note that Volvo replaced these type connections, at least on the 31/41 series engines, with normal hoses and clamps.

[Tillsbury]

Originally Posted by sailah

If you are in the US, in Cape Cod, there is an excellent machine shop I have used called Turn Wright Machineworks. Keith Fenner has all the skills and tools to do exactly what I outlined. I used him to weld a boom back together during a race as well as a number of other things. His primary business is marine shafting. He has some pretty cool YouTube videos about marine specialties to get a sense of how he tackles projects.

This would be a simple one I think.

https://turnwrightmachineworks.com/

Welding a boom back together during a race? Now that's skill and commitment...

[sailah]

Originally Posted by Tillsbury

Welding a boom back together during a race? Now that's skill and commitment...

Snapped the boom on a J40 completely in half at the vang surfing downwind to start of Figawi race on my buddies boat. Carried the boom in 2 pieces through the party tent to many jeers and cheers at Hyannis Yacht Club. Drove to Keiths shop, 4 hours later we drove back with fixed boom. He sleeved and TIG welded it on Friday Memorial Day weekend at 7pm.

Went out the next day and raced, got 2nd in our class.

Still sailing and racing 5 years later.

[Boatyarddog]

Originally Posted by hd002e

The wire clip is to gently aid the pipes into the pump, not enough to keep them sealed.

I hesitated to get new seals this time around because with the heat exchanger I got a set of seals for each fitting and they were so badly leaking that I figured it would not make that much of a difference here either.

Replace those seals for sure , and any other pitted or corroded pipe.
These are really touchy, some times fitting a slightly larger 0-ring thickness does the job.

I've had more luck taking the time to renew the o-rings and fit the tubes in their bores carefully, centering them.
Then seize the tubes in place with metal clamps fitted to the cover and screwed in place.
You'll then be able to attach hoses, without "pressuring " the fitting.
You could even epoxy them in place.
Seen it done. Haven't actually tried it.
SV Cloud Duster

[sandy stone]

In my experience, the alignment of the copper tubes in the sockets is what really matters. The tubes have to go absolutely straight into the sockets in order not to leak. Look them over, you can easily bend the tubes a little by hand to make them fit right, may take a little trial and error but it is doable.