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Walther LGR take down with pics

November 20 2009 at 1:44 AM

Casey Robertson  (Login SDplinker)

In my quest to figure out why the LGR is shooting a bit slow (450fps) I decided to forge ahead and take her apart. With some advice from folks on this forum and others I was able to get it apart without too much trouble.

I plan to write up a step by step guide - haven't seen any out there and figure I could give back a bit. With regard to what I found here's how things proceeded:

Before the tear down:

[linked image]

[linked image]

From what I read there are 3 major sealing components - the breech/loading block (a seal on either side), the piston seal and the valve seal.

The piston and seal - looks OK to me.... but what's with all that goop on the piston? Is that normal??

[linked image]

[linked image]

Piston and cocking arm assembly:

[linked image]

On the LGR (and other match rifles) the breech block flips up and you load the pellet in the barrel as it's revealed when it's in the upright position. It looks like there is a little burr on the edge of the seal around the metal. You can kind of see it as a roughly triangular spot on the right side. Wondering if it should be filed/sanded down? Doesn't appear to affect sealing but maybe....

Breech block:

[linked image]

[linked image]

Loading port:

[linked image]

The trigger assembly mounts to this block:

[linked image]

[linked image]

The end block and pin that holds in the back of the cocking arm/piston assembly:

[linked image]

[linked image]

This part goes between the trigger assembly and the striker that hits the valve to release the air charge:

Based on some dried rubber shards (orange-ish in color) under the action when I pulled the stock I think there must be seals/rings that go in the round areas ....

here --

[linked image]

and perhaps here too --

[linked image]

Striker sticking up in unhinged position:

[linked image]

Here's the key part I can't get disassembled just yet - from pics online it looks like you need a special wrench. Anybody out there feeling generous? I'll pay shipping here and back! happy.gif This is the valve assembly. The valve stem sticking out gets struck by the hammer/striker which releases the charged air into the transfer port and down the barrel. There is a seal in there which is the only one left that needs inspection.

[linked image]

So all in all a lot of little rods, clips and screws but actually a pretty straightforward concept and design. If anybody has some advice as to how to clean and lube an SSP like this I'd be very grateful. And don't forget that special wrench! Figures it would take a special tool happy.gif I wish I could keep her but unfortunately all of this work will end up in the hands of a proud new owner. The condition overall is really good and it stacks the pellets but I feel it should maybe be a bit faster so I figured I'd check out the internals while I was at it.

Thanks for looking,

Casey



 
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AuthorReply
Michael Meijer
(Login M.Meijer)

Pipe wrench

November 20 2009, 7:12 AM 

Hello Casey, the tool to take the valve assembly out is simply made out of a short piece of 1/2 inch pipe or similar.
To prevent damage to the gun, a relative soft material like copper will do, as you will not use it more than once. From one end, dril a hole as to provide purpose for a bar of some sorts, the other end should end up with two prongs that correspond with the 2 slots in the lock ring.
Make sure you file these prongs straight and perpendicular to the rotation, to prevent slippage.

If tight, work with the idea that a chisel and hammer would nearly always get stuck nuts and bolts loose. Use plastic or lead as a buffer, for instance.
It is up to you to find ways to apply that principle without causing damage.
In camera repair such (loctited) items were sometimes knowingly damaged if replacements were at hand.

Take care when re-inserting the piston; you need to slide it in, using plastic sheet cut out of a bottle or similar.
When the plastic is too pliable, you can cut some material out of a soupcan.
Again, all this in the light of a single, one time procedure.

The orangy kernels is old, dehydrated grease, as I found the same in my LGR.
Somebody here will likely chime in with a sound suggestion as to what grease should be used. I used some lithium-based paste, that seems to work fine on the outside mechanism.

Interesting thread I intend to follow!
Good luck, regards,
Michael Meijer

 
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Garvin
(Premier Login Garvin2)

Great work Casey and Michael!

November 20 2009, 7:56 AM 

Thanks very much. happy.gif

The Falke forum, dedicated to Falke airguns

 
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Casey in San Diego
(Login SDplinker)

Thanks Michael

November 20 2009, 11:58 AM 

But are you sure that it's just grease? I wish I'd kept that for pics. I could match up several of the pieces puzzle-like into round sections. I decided to look up the parts diagram provided to me (not sure why I didn't look before!) and sure enough, I think there are seals/bumpers - looks like part numbers 71 and 68. My gun does not have these parts:

[linked image]

So rather than seals being 'bad' per se I have another theory. Since the release of the air charge from the valve is predicated on the striker hitting the valve stem with the proper force and duration...if I'm understanding the mechanism correctly the absence of those two pieces could be affecting the transfer of force to the striker once the sear releases on the trigger.

Won't know for sure until I can get inside the valve though. Any thoughts? Or am I nuts and I should just sell this sucker, break even and move on? I desperately want to fix it though!!

Thanks again for all the advice!

 
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FourRings
(Login FourRings)

FWIW, 71 and 68 had broken into multiple pieces in my LGR...

November 21 2009, 10:29 AM 

The replacements from JG were the wrong size and material, so I made new ones out of delrin washers.

Great post!

Mike

 
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Jim Y
(Login 1200S)

Thanks for sharing guys. I always enjoy seeing the inside...

November 20 2009, 9:24 AM 

...of a gun as much as the outside.

That grease looks like the same stuff I found inside a LGM1. I think the factory was a bit over generous in the LGM1 as in your LGR. For a replacement grease, there have been several that have been recommended to me. The gunsmith at Pilkington's uses Superlube, while the one at Neil Johnson's used a silicone grease made by a company called SSP. FWB Joint Grease and Anschutz Special Grease will also work.

Whatever product you choose, I would apply it sparingly. As an example, the Anschutz SA2002 manual describes lubricating the piston seal with a small dot of grease on the end of a toothpick.

I am looking forward to your updates.

Thanks.



Jim Y.

 
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Casey in San Diego
(Login SDplinker)

Thanks Jim...I'll look for that grease

November 20 2009, 11:58 AM 

I wonder if it has a more readily available equivalent from a non airgun source.

 
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Jim Y
(Login 1200S)

Re: Thanks Jim...I'll look for that grease

November 21 2009, 8:54 AM 

Casey,

I have successfully used the greases I mentioned except I haven't tried the one from SSP. I can find Superlube at hardware and industrial supply stores. The FWB and Anschutz greases are from air gun stores.



Jim Y.

 
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Casey in San Diego
(Login SDplinker)

Would this be the correct Super - Lube?

November 23 2009, 11:59 AM 


 
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Jim Y
(Login 1200S)

Yes, it is. I ordered a tube...

November 25 2009, 8:52 AM 

...from Pilkington's just to be sure it is the same stuff I can find locally. If you are in San Diego, you would probably find some at Ace or Truvalue hardware stores. I have a couple tubes of the grease and a tube of the oil version that I use on many things besides air guns. At the rate I am going, that's probably enough lubricants to last 15 years.

If you want more technical details, you can find the Material Safety Data Sheets at the Super Lube web site. I don't know if it's the best lube out there, but it is readily available and Pilkington's has been using it successfully for a while.




Jim Y.

 
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Nick Carter
(Login cartertools)

Valve tool wrench.

November 20 2009, 11:36 AM 

I just made a similar tool from pipe for my Haenel 310:
http://anotherairgunblog.blogspot.com/2009/11/haenel-310-disassembly-part-2.html

As you can see you choose a piece of pipe the correct diameter and mill two prongs on it to engage the slots. You could use a file and achieve the same thing quite easily. Of course if you have a lathe you can use solid instead of pipe and make the wall thickness exactly match the slot lengths, but that would probably be overkill.

Excellent writeup!

Nick,
From ruralburbian Philomath.
anotherairgunblog.blogspot.com

 
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dave
(Login arathol1)

Re: Valve tool wrench.

November 20 2009, 6:31 PM 

Better to use a socket than a pipe. That type of valve nut was used for many years by Crosman. There was a tool made specifically for that type of nut, the Crosman T 1 tool.

[linked image]

T1 tool and some home made tools using small sockets and a piece of pipe

[linked image]

[linked image]
[linked image]

 
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Casey in San Diego
(Login SDplinker)

Good pics! Any advice on....

November 20 2009, 6:48 PM 

How to cut/grind away on a socket? I have plenty of sockets I could sacrifice but not sure I have the tools to do so - I haven't dealt with cutting metal a whole lot. Thanks,

Casey

 
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dave
(Login arathol1)

Re: Good pics! Any advice on....

November 20 2009, 7:40 PM 

I used a Dremel with a cut-off wheel. Just mark out where you want to cut and have at it. Just go slow and be careful not to cut to much off.

[linked image]
[linked image]

 
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Casey in San Diego
(Login SDplinker)

Cool...just picked up a Dremel a couple months ago

November 20 2009, 7:54 PM 

With a nice little supply of those cut-off wheels for about 5 bucks. Looks like I'll finally put it to use happy.gif

 
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Michael Meijer
(Login M.Meijer)

More thoughts

November 20 2009, 6:53 PM 

Hello Casey,

I did find some internals of an LGR, but cannot make a complete picture.
However, in the e.view by Walther, # 68 is a thin steel washer, # 71 a synthetic buffer.
The latter could desintegrate easily under the pounding of the release(d) spring and time, and could have ended up as the debris you found.
The latter is no high tech, so any semi-soft plastic of 2 mm thickness should do.
This thickness is not very critical, as the valve will be opened before that opening motion is stopped against that synthetic buffer.

The e.view shows the special tool #991 you can make yourself, as well as the sleeve tool # 992 you can fabricate too.
The goo on that piston, by the way, is to lubricate it while worked.
This is a high load metal-to-metal, hence some lithium based grease should work, as it can take the pressure and is rather sticky, so has no tendency to interfere with the business of compressing.
Bear in mind too, that compressing the air here is done in a slow movement, calling for a minute, if any, lubrication.

Reading up a little, I found an interesting note: the low performance can also be caused by rust in the compressed air chamber.
Appearantly some guy found this space filled half full!
It stands to reason: this is where (humid) air is being compressed over 50 bar, with some heat, in a bare metal space.
I will look into this further if I can find my own project to run parallel with yours; my project gun did not compress and needs a total overhaul if I remember correctly.
I should be able to get some seals in Germany.

The LGR is a milestone in the developement of match rifles. And, important to most, if not all of us, equiped with an honest piece of wood, making it an all-time classic!

Regards, Michael Meijer

 
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Casey in San Diego
(Login SDplinker)

Valve tool on the way

November 25 2009, 1:40 PM 

A fine airgunner from NH was kind enough to craft a valve tool out of an old socket. It's on its way here to CA. Once I get it and have time to try it out I'll post some pics of the valve disassembly. Thanks to all who have contributed.

-Casey

 
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Casey in San Diego
(Login SDplinker)

LGR valve has been disassembled!

November 28 2009, 4:10 PM 

Further adventures in Walther LGR tear down... I was stuck at being able to remove the LGR valve assembly. A special factory tool is needed to remove the retaining screw. I tried several approaches - brass punch, screwdriver, using my Dremel to make a tool all to no avail. Then an outstanding airgunner from New Hampshire fashioned a homemade tool from a 9mm socket and shipped it out to me free of charge! I received the tool a couple of days ago and it worked PERFECTLY! The results of the valve removal are shared below. The valve assembly looks to be in good shape however there was a fair amount of 'gunk' in the compression chamber which I'm guessing should be pretty much pristine in an SSP. So once I get it all cleaned out I will likely order replacement seals since I have it all torn down. Once I get to that stage I'll post some more pics.

Enjoy and thanks again for all of the documents and advice - it's been invaluable!

-Casey

Slideshow notes: The pictures go by pretty quick. To slow them down, hover your mouse over the slideshow and pause controls will appear or click the button listed to 'view all images'.

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Casey in San Diego
(Login SDplinker)

OLD thread...but I have another LGR I'm thinking of resealing

February 21 2014, 4:57 PM 

This time I've done it before and have the valve tool. I've loaned it out several times so it's gotten good use. Thanks again to Duane in NH for making it for me!

-Casey

******************************************
CASA Member - CA Airgun Shooters Association: http://socasa.org

 
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This forum dedicated to all that enjoy collecting and restoring airguns. Have fun. Dave