Author Topic: Scored a nice ITM AT84S, but it won't run  (Read 994 times)

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Offline Bret

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #30 on: January 22, 2018, 02:48:30 PM »
I understand now.  A picture is worth a thousand words.  Thanks.

Offline Bret

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #31 on: January 30, 2018, 03:03:05 PM »
I called EAA and they asked me to send pictures.  They then replied that I could call and order the parts.  I called today and placed the order.  We'll see what shows up.  I'm keeping my fingers crossed.

Offline Hairlesswookiee

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #32 on: January 31, 2018, 11:54:36 PM »
Nice find!! I've been wanting to get one of these for a couple of months now. Now that the tax season is officially over and I don't owe any money I'm going to have to concentrate my efforts on getting one soon.

Offline Bret

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #33 on: February 04, 2018, 03:43:40 PM »
On the left is the new sear cage with the sear installed.  The old sear cage is on the right.  The new sear cage appears to me to be identical to the current production sear cages.  They didn't tell me specifically that the older pistols take the new sear cages, but I did send them pictures of the part I needed.

Bret........the little arrowhead piece is the safety detent.  On the safety in the picture you see the little spring,, the arrowhead rides on that spring with the point pointing to the little post.  On the outside of the frame there is a small recess by the safety hole where arrowhead will nest.  You flip the safety up, the detent, pushed by the spring, locks the safety in the up position.  Safety down and the detent will lock the safety down, powered by that small coil spring.  If you look at the safety, there is a small hole drilled on the side.  There is also a small hole drilled in the detent. Before removing the safety from the gun, you stick a paper clip thru the hole in the safety and thru the hole in the detent to hold those two pieces together....otherwise the dent under spring pressure goes flying.  (As you mentioned). 

To reassemble, you will need to set the detent on the spring and insert a paper clip thru both holes to hold it in place on the safety....good luck.  Do this in a zip lock bag, or that piece will go flying who knows where.
This information was spot on.  Reassembly was an ordeal.  I never want to go through that again.


Now when I try to install the slide it gets stuck at the point shown below.  Any ideas? 



Offline 75Plus

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #34 on: February 04, 2018, 06:11:30 PM »
I had a similar problem in fitting a .40 S&W 75B upper to a full Kadet frame which has no FPB lifter. The sear cage was tall enough that the slide would not slide over it. I took the edges of the cage down with a file until the .40 slide would fit over it. Only work on the narrow path that is contacted by slide. The small amount of material removed was not in any way critical to the function of the cage.

BTW CZ cages have a single digit number stamped on them which appears to relate to the height.
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Offline win308

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #35 on: February 05, 2018, 12:07:32 AM »
That "leg" of the sear spring isn't supposed to stick straight up like that...it's blocking the slide.  You may have it in upside down....I don't know that for sure, but I know it doesn't stick up like that.   Any way, in a Tanfoglio that leg rides on the safety shaft.  (I know this isn't a Tanfo, so I could be wrong on your gun).


Offline Bret

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #36 on: February 05, 2018, 09:26:22 AM »
win308, that's a good observation.  The safety actually walked out to the left while I was manipulating it.  The safety detent got launched in the process.  It's a miracle, but I found it on right out in an open area on the floor.  The safety was able to walk out because the leg of the sear spring was not holding it in place.  I bent the leg down so that now it holds the safety as it should.  I spent almost two hours trying to get everything back together last night, but couldn't make it happen.  I don't have enough cuss words for the person who came up with this design.  Poor would be an understatement.  I'm guessing that they have some sort of special tool at the factory.  I'm hoping that spring sticking up was the extent of the problem.  We'll see.

Offline win308

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #37 on: February 06, 2018, 03:16:48 AM »
The Tanfoglio safety has a notch that the spring "leg" must nestle on to prevent the safety from backing out.  With the leg bent up, the safety will always work its way out of the gun under recoil.


Offline Bret

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #38 on: February 06, 2018, 09:20:42 AM »
That's exactly what happened to me, but it's holding in place now that I bent the spring down.

Offline Bret

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #39 on: February 10, 2018, 01:01:22 PM »
OK, I got the sear cage installed successfully.  Even with the leg of the sear spring in the notch and out of the way, the slide was stopping just after the ejector went under the slide.  I installed a couple of TA90 slides on the frame and they would go all the way forward and back with no problem.  After looking at it for a while I figured out that the top of the ejector was making contact with the slide.  Interestingly, the two TA90's have an additional cut in the slide just the width of the ejector that's cut just deep enough to allow the ejector to go through without touching the slide.  I decided that my best bet would be to file down the top of the ejector as machining the slide would be a costly ordeal.  I tried using a hand file, but it was hard as can be and progress was almost not measurable.  I took it over to my bench grinder and took the top of the ejector down just a tap at a time.  After several taps and fitting trials, I had the ejector going through the slide with no resistance.  I then used a hand file to get the top of the ejector perfectly flat.  There is of course no way to know for sure, but I'd bet that the original ejector broke due to contact with the underside of the slide.

Unfortunately, there's now a new problem.  When the pistol is cocked to single action mode, the hammer falls to half-cock as the trigger is pulled.  It wasn't doing this before, but I'm guessing that a slight difference in the dimensions of the sear cage is allowing this to happen.  The SA trigger was very light before, so perhaps someone messed with it previously or it was just very light from the factory.  Any idea what I should do to fix this problem?

Offline DF_Hammack

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #40 on: February 10, 2018, 02:45:47 PM »
You said you tried to use a hand file, but it was too hard an the file just skittered off. Then, after grinding. you dressed it with a file. Sounds like you need to re-harden the ejector, or you will have serious wear issues
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Offline Bret

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #41 on: February 10, 2018, 04:41:36 PM »
When I dressed it, not much was taken off even though I had to file for a while.  The top of the ejector isn't a contact point anyway.

I took the AT84S to my range this afternoon and put 49rds of Magtech 115gr FMJ through it.  The good news is that the ejector seemed to perform just fine.  The bad news is that I've now discovered another problem.  Over half the time, the spent case didn't extract from the chamber.  Now I've got to clean this thing up to see if I have an extractor issue or a chamber issue.  Interestingly, when shooting in SA mode, it didn't feel like the pistol was falling to half-cock.  I guess this is because I'm pulling back quickly when actually firing it.  I now think that it is quite possible that the drop to half-cock problem existed before I replaced the sear cage.

Offline Bret

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #42 on: February 11, 2018, 06:05:46 PM »
I cleaned the pistol yesterday.  When I hand cycle ammunition through it, it runs 100%.  I took it back to my range today.  I put 10rds of Magtech 115gr FMJ and 10rds of Winchester NATO 124gr FMJ through it.  There were 8 failures to extract from the chamber with each type of ammo.  It's interesting that the pistol extracts cartridges when hand cycling, but the spent cases don't extract 80% of the time.  So now I have two problems.  The first is the hammer falling to half-cock when shooting in SA mode.  The second is the failure to extract.  Could they possibly be related?  I guess if I fire the pistol in DA mode and it extracts every time, then they're likely related.  Thoughts?

Offline schmeky

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #43 on: February 11, 2018, 09:34:51 PM »
A new ejector could be welded in place.  Done right it would be fine. 

Offline Walt Sherrill

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Re: Scored a nice ITM AT84S, but it won't run
« Reply #44 on: February 12, 2018, 07:51:27 PM »
You may want to get a gunsmith to look at the sear assembly.   Firing DA, the sear isn't used.  Firing single action, it is... and maybe something isn't working as it should, a spring might be binding, etc.

The force used to manually extract a round from the chamber is quite different from the forces encountered when the slide is cycled by rounds fired.  It may be that the extractor spring is just weak. The fix may be as simple as getting a new extractor spring... (I don't remember, but Wolff extra strength extractor springs MIGHT work in the AT-84s.)

I'm not going to strip mine down to be sure, but most of the Tanfoglio-based guns had an open channel (opening into the firing pin chamber) under the extractor.  With CZs, crud could build up in that area and keeping it clean would improve extraction.   I don't think that is a problem with the Tanfoglio version of the CZ pattern.  But I think the spring worked in the say manner.  (Think, but am not absolutely sure about it.)   EAA may have parts for that, too, if the CZ extractor spring doesn't fit. 
« Last Edit: February 12, 2018, 09:59:52 PM by Walt Sherrill »

 

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