This thread is both interesting and educational.

To better understand, I researched stainless bolts in aluminum. Not surprised that the stainless bolts are not coming out of the aluminum due to the two dissimilar metals and galvanic corrosion (transfer of electrons from the aluminum to stainless}. Water makes this problem worse, especially more so with salt water.

One of the solutions given in this scenario is using through bolts with nuts rather than threading the bolt into the aluminum.

Something I did not know ... thanks for the education.

I too find this thread to be informative, and especially so, since a recent storm lifted and broke a leg off of my wrought aluminum patio table.

The leg was bolted to the table top and broke off when I attempted to remove it. There is a stub protruding from the table top and I can move the bolt with vise grips and penetrating lube, but, it is now rounded off and I can't back it out any further.

Am I also stuck going to a machine shop too?

Galvanic corrosion happens with roofing all the time. Roofers use steel nails with copper and aluminum flashing, a big no no.
It also happens with pressure treated wood and aluminum flashing.

quote:

One of the solutions given in this scenario is using through bolts with nuts rather than threading the bolt into the aluminum.

Something I did not know ... thanks for the education.

Correct, but even if you do that and the bolt is stainless it can corrode and weld to the aluminum, so it's best to put a dab of anti seize on the bolt area where it contacts the aluminum, threads or not it's the contact.

Salt water isn't good on any metal...

A good anti-seize grease would prevent this. There is a marine version. Loctite makes good anti-seize.

https://www.henkel-adhesives.c...loctite_lb_8023.html

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Good point. What about putting the anti-seize on the shaft of the bolt, and a dab of lock-tight on just the nut? With a washers under both the head of the bolt and the nut at least with have a chance removing if needed in the future.

Wherever the steel touches aluminum you will get galvanization... I wouldn't worry about the nut on the bolt as much as the bolt inside the aluminum housing area.

The aluminum corrodes, and the corroded material fills the gap between the two metals. With enough corrosion, pressure builds up and locks the bolt in place.

Last update:

While the jet pump housing was at the machine shop, I found the source of my over heating problem, pictures below. The first picture is the J-pipe that comes off the exhaust manifold and goes into the muffler. Cooling water flows through the J-pipe then through three 1/8” hole into the muffler. Two of the three holes can be seen in the first picture. All three holes were blocked. The second picture shows the crap I was able to knock out of the J-pipe with a 3/16 drill bit for reference. There’s no way the bigger pieces got past the raw water strainer, they’re just too big. They look just like the crap I clean out of my parents’ faucets every year. Since it was used from my parents’ lift and flushed with their hose and water, I’m guessing that’s where it came from. The flush port bypasses the raw water strainer.

Now, I took it out this morning and it ran great. With 1-3ft waves, I really couldn’t open it up.

The threads on the housing are are bit loose due to the material lost from the corrosion. I’m going to fix this when I get back to Florida by installing stainless steel Time-seers with marine thread locker. I thought about using through bolts, but you wouldn’t be able to remove them with the whole assembly installed in the hull. There’s no way to get a wrench on the backside. Being able to take them out and removing the Venturi nozzle while the pump is still attached to the hull makes removing and especially reinstalling everything much easier. I spent 30 minutes trying to squeeze my hands past all that just to install the 4 nuts, washers, and lock washers on the studs for the pump housing.

quote:

Originally posted by Captain Morgan:
Galvanic corrosion happens with roofing all the time. Roofers use steel nails with copper and aluminum flashing, a big no no.
It also happens with pressure treated wood and aluminum flashing.

And more people will be learning about galvanic corrosion in the future, because some garden hose manufacturers are cheapening out and using aluminum hose end fittings.

Good catch realizing that the water used for flushing introduced that debris ahead of the strainer. Too bad the bolts sheared in that pump casting.

Don't know but this looks interesting, it showed up on my YouTube watch list out of the blue.