Home Forums Hunting & Shooting Gunsmithing Unfreezing a Lyman 48

I've got a nice sporterized Springfield '03 action with a Lyman 48 rear sight attached. The sight has the 120MOA elevation slide and target knobs.

The problem is, the sights adjustments are frozen. There is some surface rust but no pitting or obvious corrosion preventing the knobs from moving. I haven't tried moving the knobs with more than firm finger pressure because I don't want to strip the adjustments.

What would be the best way to "unfreeze" this sight? Penetrating oil? Disassembly? If disassembly is the way to go, are there any manuals or schematics available online?

You will get lots of recommendations for Kano's Kroil and that is indeed good.

However, there may be something better:

Penetrating Oil Comparison

Machinist's Workshop magazine tested penetrating oils for break out torque on rusted nuts. They arranged a subjective test of all the popular penetrating oils with the control being the torque required to remove the nut from a "scientifically rusted" environment. The results are as follows:

Penetrating Oil..... Average Torque
None ..................... 516 pounds
WD-40 .................. 238 pounds
PB Blaster ............. 214 pounds
Liquid Wrench ..... 127 pounds
Kano Kroil ............ 106 pounds
ATF-Acetone mix....53 pounds

The ATF-Acetone mix was a "home brew" mix of 50-50 automatic transmission fluid and acetone.

The only issue is that the 50/50 mix has a very short shelf life. Mix only enough for what you are going to use immediately.

Note that the test was on threaded fasteners, in your sliding application the best may be something else (Kroil, I'd bet based on my experience!).

John

You're right in not wanting to force the issue with that sight. Replacement knobs are made of unobtanium, but they do turn up on fleabay periodically.

To disassemble the slide from its base, you unscrew the little knurled knob on the front side of the base and then push it in, which should free the slide so it slides up and out. (That knob works like the locking winding stem of a wrist watch, if that helps.) You can now get at the hidden base mounting screw too. Take the base off and clean all the crud out of it also. At that point I would give the whole works a good 2-3 day soaking in penetrating oil and see if the knobs turn. They're probably frozen by dried out old 3-in-1 oil.

If the dis-mount screw is frozen up too, I would dismount the gun from the stock and soak the whole works in penetrating oil. Basically, the slide has to come out if a thorough cleaning needs to happen.

I recently faced the exact same situation with a Lyman 48 on a
Springfield 1922 M2. The lock knob was frozen from the effect of who knows how many years of gummed up gun oil. I applied Kroil
librally in both ends of the lock assembly and let it soak for 24 hours. Still could not move it with finger pressure so I tapped it
with a rawhide mallet until it finally broke loose. The sight slide would still not budge, so another soaking with Kroil overnight. Gentle tapping from the bottom while holding the lock
mechanism in the free position. Tapped the sight slide all the way out as it would not move under finger pressure. Once the slide was removed I had access to the base screw, removed the base from the rifle and dumped all the parts into denatured alcohol to remove all the gummy oil and crud. Once clean I treated all the moving surfaces to a light application of gun oil and reassembled the sight. Worked just like they were designed
to, one of the best sights ever designed in this country a true classic. Ready for another eighty years of faithful service.

If all else fails, you might run it thru an ultrasonic cleaner. Or maybe before anything else.

Kroil soak.

Bucket of diesel for a week w/ barreled action-Muddy

First is to soak it in penetrating oil for a good 2-4 days, then try to turn the cranks.

If that fails then you have to address the rust, and that means you're going to lose the finish that's on the sight. Best way is to soak it for several hours in a 50/50 mixture of water and white vinegar. Do that for 8-10 hours, then back into the penetrating oil. If that doesn't work, you're screwed.

Oh yeah, just thought. Before you go to the vinegar solution, give this a try. After a soak in penetrating oil, take it out and try to turn the screws. If they don't turn, then take a can of canned air, turn it upside down and spry directly on the head of the screw, being careful not to get it on the rest of the sight. Then heat the rest of the sight either with a soldering gun (not a soldering iron, won't get hot enough) or a torch. The soldering gun is best because you can better localize the heat. The idea is you want to make the sight expand and use the freon from the canned air to make the screw contract. It works, but generally when I do that I'm working on something larger. Best of luck to you sir.

Do the vinegar thing as a last resort.

The canned air thing hadn't occurred to me. They make a spray for electronics diagnosis that gets even colder. Finding a part with intermittent failures can make you nuts. Freezing a part will usually make the fault show itself. The good stuff can get you down to -60F.

It's common stuff, Radio Shack stores used to carry it. But don't know if they even sell parts now, haven't been in one for a long, long time.

Chances are it's more about gummed up oil than rust and I'd degrease with a brake clean or acetone soak/scrub, wipe it really dry, then use the ATF/Kroil/etc... and work it loose till disassembly. Then degrease/scrub again to clean it all up and re-assemble after lightly lubing.

I know most of you guys have tumblers for cleaning brass, another thing you can use the center bolt like a small impact tool for freeing up rusted parts, like an ultra sound the high speed vibrations will loosen many a stuck part. The knob on mine is plastic and does not leave any marks, just a thought.

Now that is a good tip !

gnoahhh, the little plate on the end of my windage slide of my 48S behind the windage knob spring washer is loose allowing the cross slide to much wiggle. Are there 2 screws behind it? How can I get at them? MB

I can picture that little plate but not its attachment but I'm at work right now and they frown upon my storing rifles here at the school. I'll look when I get home, if no one else responds between now and then.

When rust and corrosion is a problem...believe it or not plain old water or salt water works faster than anything. (A homeopathic approach?) Pins, threads, shafts and bushings. Little bitty gun parts..I'm not sure. Anyway, trust me, I was a engineer on big crane barges and tugs in oil and construction and had to maintain deck machinery, cranes, winches, pumps, generators that were exposed. The old boy that broke me in knew his business. On threads he would heat the most accessible part with a small torch tip, and then carefully drip water in the joint between the two stuck parts, several times if necessary, letting steam and water do it's job. Can't be beat for Cat turbo and exhaust manifold bolts. It just works.

To answer the question regarding the windage plate, there are two screws attaching it. To access them the windage knob must be removed, it is held onto the shaft by a small slotted set screw. Loosen the set screw and slide the windage adjusting knob off along with the spring detent plate and you will then have access to the two screws that attach the plate that is loose. Tighten them and that should take care of the wiggle in the windage cross slide.

Thanks guys I got it figured out after pulling the staff last night. MB