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MP 40 repaired
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Author:  robipaul [ Fri Feb 07, 2014 6:41 pm ]
Post subject:  MP 40 repaired

greetings

well its finally done, my S&W MP 40 "leaking at the barrel" has been repaired, took long enough to get the parts, and a few hours just now to get it to work

when i first took it apart to investigate, i noticed the seal of the valve assembly was leaking CO2, tried to get either a new seal or new valve, but this pistol being so cheap, Umarex does not service this pistol with parts

thanks to the gracious donation of Jay AKA "goldenkorsic" on CAF, i was able to get his damaged MP 40 to repair mine and Murray's MP 40 damaged trigger

it took a few tries, but got it to work, turns out it wasn't the seal as much as the valve body, the donor pistol's seal looked ok, but fit very loosely, and upon trying it, it still leaked, i noticed the taking out the seal of his MP 40 was very difficult as the fit was very tight, then i figured it out, it was a badly machined valve body, as soon as i used the donated valve body and seal, thing would work just fine......or so i thought, turns out the the donor pistol had a thick seal that prevented the cartridge from piercing and a bad needle, so had to take the thing apart again and used my piercing needle and seal, so a mix match of parts to finally get it to work

all in all, its now a great BB shooter, with a bonus of having an easy trigger since i molied all moving parts of the action, it reduced its pull weight by about half, i included a few pics to demonstrate the said parts

Attachments:
valve body.JPG
valve body.JPG [ 167.44 KiB | Viewed 494 times ]
needle and seal.JPG
needle and seal.JPG [ 251.43 KiB | Viewed 494 times ]
barrel action.JPG
barrel action.JPG [ 207.5 KiB | Viewed 494 times ]

Author:  robipaul [ Fri Feb 07, 2014 6:45 pm ]
Post subject:  Re: MP 40 repaired

BTW, neat little trick if your dealing with a few screws and don't want to mix them up, download and print of your gun, and make little holes of where the all the screws are located

Attachments:
IMG_1923.JPG
IMG_1923.JPG [ 132.25 KiB | Viewed 489 times ]

Author:  GoldenKorsic [ Sat Feb 08, 2014 2:21 am ]
Post subject:  Re: MP 40 repaired

I'm starting to wonder if it wasn't so much a 'damaged needle' in the donor gun as just really lousy quality control on umarex's part, as that needle had never pierced a cartridge from the time I bought it in march 09 and sent it off to you last month.
The entire pistol seems to be made with "soft spots", that break with little warning and don't hold up well at all. From the magazine release, to the barrel assembly, to the valves and seals. The damned thing really needs to be babied.

Glad you got it working though, Happy shooting.

- Jay

Author:  robipaul [ Sat Feb 08, 2014 6:07 am ]
Post subject:  Re: MP 40 repaired

GoldenKorsic wrote:
I'm starting to wonder if it wasn't so much a 'damaged needle' in the donor gun as just really lousy quality control on umarex's part, as that needle had never pierced a cartridge from the time I bought it in march 09 and sent it off to you last month.
The entire pistol seems to be made with "soft spots", that break with little warning and don't hold up well at all. From the magazine release, to the barrel assembly, to the valves and seals. The damned thing really needs to be babied.

Glad you got it working though, Happy shooting.

- Jay



i guess that if Umarex wants to sell a cheap pistol, they can't be spending too much money on QC :lol: , was a weird thing to see, a seal that's too thick, and a needle that's too short, and also damaged when compared to mine, then if i look at my MP40, a valve body that has its hole too large for a tight fit seal, in fact i'm surprised it sealed at all, but since the valve body of the donor pistol seems to be the correct diameter, i'm figuring i can keep my own seal as a spare :)

although both of our MP 40 were bought in about the same time period, there were other differences, the barrels may be of different material as they are different color, and the ring holding the needle in place are different material, mine was aluminium, and yours made of brass :roll:

Author:  GoldenKorsic [ Sat Feb 08, 2014 10:02 pm ]
Post subject:  Re: MP 40 repaired

Did you compare the serial number range? I believe the donor pistol was mfg'd in 2008, so there is a chance that in the time between pistols they cheapened the parts and process. Not surprised about the change of o-rings though. My guess is they opted for a heftier one for durability (or vice versa for cost effectiveness. Only you will be able to check with the serials).

I would bet my quarter on the barrel's being the same material, just with a difference in how the finish has fared. (or a change in the process and coating)
I have seen a pair of rifle barrels look like different materials, where the only actual difference was the finish being much lighter on the one. (I also remember it stirring an OCD response out of my brain and it bugging the crap out of me for days because I couldn't stop thinking about it.

What also comes to mind is my experience with a home bluing kit and leaving some items submerged longer than others, and the resulting "depth" of the coloring.

Author:  robipaul [ Sun Feb 09, 2014 8:18 am ]
Post subject:  Re: MP 40 repaired

GoldenKorsic wrote:
Did you compare the serial number range? I believe the donor pistol was mfg'd in 2008, so there is a chance that in the time between pistols they cheapened the parts and process. Not surprised about the change of o-rings though. My guess is they opted for a heftier one for durability (or vice versa for cost effectiveness. Only you will be able to check with the serials).

I would bet my quarter on the barrel's being the same material, just with a difference in how the finish has fared. (or a change in the process and coating)
I have seen a pair of rifle barrels look like different materials, where the only actual difference was the finish being much lighter on the one. (I also remember it stirring an OCD response out of my brain and it bugging the crap out of me for days because I couldn't stop thinking about it.

What also comes to mind is my experience with a home bluing kit and leaving some items submerged longer than others, and the resulting "depth" of the coloring.



think you are right about the barrel, probably just the finish

the serials are;

donor 08C02993
mine 10E11417

so if i'm reading this right, yours would have been made in 2008, and mine in 2010, and the letter may indicate a different factory, but i can tell you that the fit and finish, as well as the quality of materials appears to be better in the donor, and that would make sense IMO, cut corners, keep the price down :lol:

Author:  GoldenKorsic [ Sun Feb 09, 2014 8:35 am ]
Post subject:  Re: MP 40 repaired

My guess would be a different production run rather than factory, but that's pure speculation on my part. I would fire off an e-mail to umarex asking about their serial number schemes but the last time I had to contact their customer service about something (still unresolved), it left a bad taste in my mouth. Only marginally faster than crosman, but less informative and helpful.
You should keep the remaining donor parts in a box just in case something else breaks. It would be "justified clutter" in my opinion.

I found the original paperwork from it after I sent the donor to you, the leaflets, manual, and the registration card. I'm not really sure why I never contacted them about the warranty work at the time to see what they would have said.

Was yours boxed, or in a blister pack?
Umarex (and crosman) seem to use both interchangeably for their pistols, differing only in region. Mine was in a blister pack, which is why I only saved the papers and the not the rest of the packaging.

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