LG90 Problem With Loading Hatch Flying Open.

[zooma]

We have a Walther LG90 in our club that keep blowing the loading hatch open and when this happens it throws out the seal that is mounted in the hinged loading hatch - the seal that faces downwards when closed.

After several fretful events each night where every shot snaps open the loading hatch and throws out this seal the rifle mysteriously settles down and then behaves and works perfectly all night.

When we are having this problem and the loading hatch is closed the rifle can be lifted by the loading hatch so the mechanical lock is very strong suggesting that something is releasing this locking latch when the trigger is pulled.

Whatever it is that causes the problem it does eventually disappear so we are left very frustrated with no clue as to what the problem is and why it cures itself.

After a successful nights shooting (eventually) with the LG90, the rifle has won back favour and is well liked BUT when taken out of its case and shot the next night we are right back to square one again as the loading hatch blows open we have to play the "find the seal" game for far too long before the rifle becomes shootable again.

Fitting new seals does not help at all.

Does anyone have an answer or can let us know what may be going on inside this temperamental LG90 rifle please?

[PhatMan]

Bob,

I have had a peek on the Interweb, and it seems that the consensus is that the barrel needs moving slightly away from the breech-block.

There is this post here by RobinC WRT the LGR on AigunBBS : http://www.airgunbbs.com/archive/ind.../t-429187.html

RobinC
24-01-2010, 01:59 PM
Eric
All the statements made are correct, my wife shot an LGR at international level in the 80's, still has it, has just returned to shooting and is still using it and is not interested in changing to any thing newer. They are easy to work on, I changed the valve, buffer, and breach seals before she restarted and it performs perfectly.
If you want to try both we have them as club guns at our target club in Norwich, you can e me on robin.carter80@ntlworld.com for details
The following procedure is the official way used by Walther to ensure the seal fit is correct and with no leaks. When you change the breach seals, it is very important to clean the old ones out of the block carefully as some were put in with something like loctite and if not cleaned out it causes the problem you describe. I refit them dry which is no issue unless the block has been butchered, the block is alloy and if the seal recesses have been scrapped out it may be best to replace the block. With the rifle held in a vice by the barrel (pad with cloth and wood) vertically, action up, slacken the barrel lock screw with an allen key and with the breach closed let the weight of the action settle and then just nip the lock screw and check the breach block fit. It should be firm with no noticeable movement, I sometimes give the action a very light tap with a soft mallet with it nipped to get that last thou of movement out but take care to not over strain it other wise it will pop open in use. Its a delicate operation to get the balance of no movement with out over crowding it. When correct, tighten the barrel lock screw, there is no torque setting but it should be very tight, and then recheck that the fit is the same after it is all tight. In use don't snap the block closed, lift the tab, close the block and close the tab.
Best regards
Robin

Might be worth trying something similar on the LG90 ?

Have fun & a super Christmas & New Year

Best regards

Russ

[zooma]

Bob,

I have had a peek on the Interweb, and it seems that the consensus is that the barrel needs moving slightly away from the breech-block.

There is this post here by RobinC WRT the LGR on AigunBBS : http://www.airgunbbs.com/archive/ind.../t-429187.html

RobinC
24-01-2010, 01:59 PM

The following procedure is the official way used by Walther to ensure the seal fit is correct and with no leaks. When you change the breach seals, it is very important to clean the old ones out of the block carefully as some were put in with something like loctite and if not cleaned out it causes the problem you describe. I refit them dry which is no issue unless the block has been butchered, the block is alloy and if the seal recesses have been scrapped out it may be best to replace the block. With the rifle held in a vice by the barrel (pad with cloth and wood) vertically, action up, slacken the barrel lock screw with an allen key and with the breach closed let the weight of the action settle and then just nip the lock screw and check the breach block fit. It should be firm with no noticeable movement, I sometimes give the action a very light tap with a soft mallet with it nipped to get that last thou of movement out but take care to not over strain it other wise it will pop open in use. Its a delicate operation to get the balance of no movement with out over crowding it. When correct, tighten the barrel lock screw, there is no torque setting but it should be very tight, and then recheck that the fit is the same after it is all tight. In use don't snap the block closed, lift the tab, close the block and close the tab.
Best regards
Robin

Might be worth trying something similar on the LG90 ?

Have fun & a super Christmas & New Year

Best regards

Russ

Ah Yes - I should have thought this through better and asked Robin first! He has a lot of experience with Walther rifles and this could be the answer to the problem.

I will try this idea as it sounds simple enough and as you suggest it could apply equally well to the LG90 as it has a similar opening breech block mechanism.

The base of the seal groove is butchered on this particular LG90 breech block - it had a "O" ring glued in it with a small dab of silicone when we first had it so maybe I should bed the new seal(genuine Walther part) in with some sort of Locktite and then try the adjustment method as described above.

Longer term I think I need to find a replacement block so I will look around to see if they are still available.

[RobinC]

Bob,


[B]RobinC
24-01-2010, 01:59 PM
Eric
All the statements made are correct, my wife shot an LGR at international level in the 80's, still has it, has just returned to shooting and is still using it and is not interested in changing to any thing newer.
Russ

Bob
That is certainly the problem, they are a touch "by feel" to set up, too tight they pop open, too loose they leak. I always did them dry, I'll e mail you with the best way to do it.

Quote above from me in 2010 "and is not interested in changing to any thing newer". Oh how naive and inocent I was then!!!! "Just having a play in retirement she said!
Oh no, no, first she had a new Walther LG300 Junior, then chased the factory for an LG400 and had a special Walther, an LG400 expert system in an LG300 Junior stock, still loves that fortunately!

Have fun
Robin

[zooma]

Thanks Robin,

I will give it a try

[zooma]

Tonight I loosened the front and rear barrel clamps on the LG90 and noticed that it is not possible to rest the weight of the action on the barrel as the rifle has a false barrel extension - the barrel itself ends some distance back.

I closed the breech and pushed the barrel up to the seal and tightened it back up again and set off to the club - taking my long handled 4mm Allen key with me!

The first shot saw the loading hatch flip open and the now familiar search for the flipped-out seal started again - so out with the 4mm Allen key ready to try again!

The barrel clamp screws were released and this time the barrel was pushed slightly more firmly against the closed breech seal and the second was shot taken . . . . and again we found ourselves looking for the seal that had flown out again.

The third attempt saw the barrel being pushed hard against the closed breech seal by a "volunteer" ( thanks Mark) as I tightened it up quickly before any pressure was lost.

This time the rifle shot without incident and continued to do so all night - success!

However we have been here before - but never so early in the evening - and with a lot less time spent searching for missing seals !

The acid test will be what happens the next time the rifle it taken out of the case - if it starts to flip the loading hatch and jettison the seal again then we have made no progress - but if it shoots as it should right from the start then we have found the solution and know what to do if it happens again.

It is also the correct procedure to follow after a seal is changed to get the correct adjustment but it is definitely a case of having the right "feel" and not working to a fixed measurement or pressure setting.

[XDRIVER]

No problem Bob, glad to help. Superb rifle both in looks and to shoot. Looking forward to getting one myself with hard case of course 😀

[PhatMan]

Bob,

Spiffing

Once adjusted, I would doubt you would need to re-do this the next time you change the seals - I certainly didn't need to when I replaced the seals on my LG90.

Have fun & super Christmas

Best regards

Russ

[zooma]

I took the LG90 into the garage tonight and put 6 shots though it - not much to brag about perhaps - but the rifle shot without the loading hatch flying open so hopefully ( thanks to Robin's advice) we have fixed the problem.

It is always the first few shots when we have had the problem so this "non-event" is just what we wanted to see.

With the slight modification to Robins step by step guide (due to the "false" barrel extension) we have a good method of fixing the problem that will apply equally to the LGR, LGR Match and LGR Match Universal that feature the same type of loading system.

Thanks Robin - A good workshop tip that will be helpful to a lot of Walther SSP rifle owners in the future.

[RobinC]

Glad its working, I think the adjustment has helped, but I'm not convinced its all the issue, I've emailed with some further guidance, but the essence of my concern is I've never seen one eject the seals when the breach block flys open.

For those with LGR (or type) actions, I'll add this further guidance, that the seal replacement is best done with the breach block removed, and the seal recesses should be spotlessly clean with no remaining bits of seal or glue or what ever has been used to stick them in, BUT do not scrape them as the fit should be tight.
To use only the correct pattern seals, they are not O rings, they are square section and have a correct "way up". The base to seat in the block is square, the face has a curve.
Regardles of how they were originally done, fit them dry or with a slightest touch of grease or Vaselene and firmly press into the recess, the edge will be near enough flush with the block and only the curve will stand out.
Refit the block and reset the barrel tension on every seal change.

Have fun and may your antiques last for ever,
Merry Xmas and a great new year.
Robin

[zooma]

Hi Robin,

I am using genuine Walther seals and have fitted them with the square base downwards.

The LG90 has quite a strong opening spring on it that flips the loading hatch open after each shot quite quickly but the seal never comes out - this only happened (before the adjustment) when it was being blown open as the shot was taken.

Thanks for your help and guidance - Happy Christmas and Best Wishes for 2016

[RobinC]

Great, that does sound like it was just an adjustment issue, I've never seen an LG90 so I'm fishing in the dark as I'm still thinking in LGR,

Merry Xmas to everyone,

Have Fun, and May your classics go on for ever,

Good Shooting

Robin

[himself]

Great, that does sound like it was just an adjustment issue, I've never seen an LG90 so I'm fishing in the dark as I'm still thinking in LGR,

Merry Xmas to everyone,

Have Fun, and May your classics go on for ever,

Good Shooting

Robin

Hi Robin .
Wishing you and yours a Happy Christmas, good to see you are still there with sound advice. Regards John F.

[zooma]

I have had an enquiry from a fellow BBS member about a flying breech seal on his LGR so I thought I would bring this thread back to the top for him (and others ) to see as the tip from Robin certainly cured my similar problem with my LG90 that shares the same seal - and the same problem - often after they have been shipped or bumped - or sometimes when a new seal has been fitted.

Hope this helps

[Mark D]

I have had an enquiry from a fellow BBS member about a flying breech seal on his LGR so I thought I would bring this thread back to the top for him (and others ) to see as the tip from Robin certainly cured my similar problem with my LG90 that shares the same seal - and the same problem - often after they have been shipped or bumped - or sometimes when a new seal has been fitted.

Hope this helps

Phew ! for a moment I thought I was going to have to report you to the PWSSPA ( Walther Preservation of Single Stroke Pneumatics Association)