Aluminum seized in aluminum

philminotti · #1 (**permalink**) 09-06-2009, 01:51 PM

About 5 months ago, I mocked up my remote oil filter setup. I have (had

) a billet remote oil filter adapter block and was using aluminum 1/2" NPT to -12 AN adapters. I screwed the NPT-AN adapters into the block HAND tight (ok maybe fist tight) but definitely no wrench used. I didn't use antiseize figuring hand tight is just that. You know where this is going. Today, I went to final assemble the system, lo and behold one of the adapters was totally seized into my nice billet block. I had to use major force to get it out, naturally ruining both adapter and billet block.

Would it be better to use a steel NPT-AN adapter? Any ideas?

phil

brettco · #2 (**permalink**) 09-06-2009, 04:14 PM

Aluminum fittings are all that are used in racing today and I don't think thats the problem. Pipe threads do bind against each other but even with a wrench it shouldn't be a big deal.

Argess · #3 (**permalink**) 09-06-2009, 04:31 PM

You could try a little oil or grease on the threads. Possibly liquid teflon pipe goop. I use yellow teflon tape frequently.

I also use brass fittings into aluminum. AN fittings are often aluminum and I'm not 100% sure, but I think they may not be NPT threads. So you may have had threads starting to interfere with each other.

Maybe Google "galling" where the friction of tighening actually welds the metal together and see what remedies there are.

In your situation, putting the whole thing in the deep freeze for a while might have helped as the fitting should shrink more than the housing. Pouring hot water on the housing after the deep-freeze thing might hep even more. But nothing will help if it did gall.

WD40 might also have helped, but regular penetrating oil doesn't seem to do much for aluminum corrosion.

OOPS...I just reread and see you used an NPT-AN adapter. er.....or maybe an AN-NPT adapter?

RICK LAKE · #4 (**permalink**) 09-06-2009, 04:57 PM

philminotti Phil antisieze is the best for your problem. If you had applied heat to about 200 degrees you would have gotten the fitting out unless it was cross threaded. Red rtv sealer works too but down on my list. Rick L.

trularin · #5 (**permalink**) 09-06-2009, 07:20 PM

If you can get it, cop-a-slip works well.

Just my $0.02

Bobcat · #6 (**permalink**) 09-07-2009, 10:08 AM

You asked if steel fittings would work better . We had the same problem with them on hydraulic systems ( aluminum manifold blocks and steel NPT fittings ) .... after being torqued down and going through many heat cycles , they "froze " in the blocks . We used to take a hammer , put a piece of steel pipe over the fitting and on the wrench flats and give it several good whacks to break it loose .... but these were 2 " fittings . With aluminum , Never Seize seems to work ok , but the fitting will still be difficult to remove after a long period .
Given the option , I would always use SAE straight thread " O" ring fittings .
I hate to use NPT on anything , but sometimes there is no choice .

RICK LAKE · #7 (**permalink**) 09-07-2009, 10:27 AM

philminotti Phil you where right, I look at the print outs again Flywheel numbers. Car will run in the 11's on street tires. Rick

philminotti · #8 (**permalink**) 09-07-2009, 01:18 PM

Bobcat got me thinking...

I ASSumed the adapter block was NPT. I think it actually is AN straight thread O-ring. I'll have to confirm that with Gessford tomorrow. Assumptions will getcha every time...

phil

PatBuckley · #9 (**permalink**) 09-08-2009, 08:49 AM

Aluminum on aluminum without any lubricant WILL gall.

Maurice Butler · #10 (**permalink**) 09-09-2009, 01:13 AM

so will stainless if the bolt and the nut are excaltly the same grade

lovehamr · #11 (**permalink**) 09-09-2009, 04:23 AM

I had stainless VC bolts gall in an Ali Edlbrock head and wound up having to drill the damn things out. Talk about no fun.

Michael C Henry · #12 (**permalink**) 09-19-2009, 04:55 PM

If your sure that they are allready galled together? You'll have to sacrifice one of the parts. Preferably the plug. When the hull drain plugs where seized in the alluminum hull of M113's. these plugs were lage about 1 1/4"" NPT with a large 3/4" square drive socket. I'd drill out the center of the plug as far as the wrench socket would allow, then take a die grinder and a rotary file ( carbide bit) preferably a non ferous type so it can be cleaned when fouled. They foul when grindind on alluminum. Then Id start cuttung the remains ot the p[lug intp three or four pieces. The first piece would be a section cut with clearence in two cutts, to be slid inward from the circle creating a gap in the rest of the ring to calasp inward.. Grind untill you see the pattern from the thread shows. I've been known to cheat and then use a hacksaw blade to cut farther into the threads then smack with a hammer and chizle to break that piece loose and remove . Once that portion of the circle of plug is removed one or two more weakened sections can be beat inward on the circle calasping the circle enough to remove the reains of the old sacrificed plug. I'd then go back and retap the housing a little more to clean it all up. Then teflon tape would take care of sealing lubericant, and anti rattle requirements.
Next time use a steel or brass plug. They are stronger than the alluminum and if they get stuck you can smack them to free up or heated to expand then wait till cooled down .. When you heat the plug it trys to expand pushing the outer housing, especially alluminum, then shrinking as it cools, giving freedom the plug didn't have before. One you start transfering metal as in galling it is no longer a simple unscrew it any longer. If you have seized , forcably twisting the plug will just ruin both plug and housing.