I do not know if this will help but I give below my experience of an Erma:Originally Posted by 45flint
Unjamming an ERMA ELG10
I was given a non-working Erma ELG10. Problem was how to sort it as the underlever was fully open and would not shift. I sought a little help from Google and found my way to 'deejayuu' here on the BBS, who had stripped and rebuilt a ELG10 and was able to offer thoughts and an exploded diagram. Jules posts on the topic are available via a search. Thank you Jules. To cut a long story short we both concluded that the issue was related to the abt mechanism so:, with the frame cover out of the way I could see the compression cylinder stuck at the trigger end with a menacing compressed spring inside. Nothing would move... the trigger did nothing, the underlever was solid. So I strapped everything up, secured it in a vice and tapped out the abt pawl pin .... As I finally released my punch from the abt pin hole it all came free and the compression cylinder would return to rest. Part way there.
I removed cylinder and piston plus spring to look inside. This meant prising the compression cylinder plus part compressed spring out of the frame. Compression cylinder is secured to the underlever linkage by a pin but, in hindsight, did not need to be removed. Nothing obvious was revealed but I took a few bits out anyway to check against the parts diagram. Put these bits all back together, checked working of abt pawl and slide rod ... seemed OK. Assembled minus spring and after a bit of fiddling it worked ... piston retained by the trigger sears and the cylinder returning to base as the underlever was closed. Not too sure why but I can say that when I released the abt pivot initially, the cylinder returned to base complete with piston i.e. the piston had not engaged with the sears. Maybe this was related to a part I had removed and replaced ...part 1021 on the exploded diagram termed a locking bolt. It is an angled flat plate with a small tab at one end. It locates on a spring such that it pivots. My first success at locating it on its pivot just did not seem right as the tab rode on the trigger mechanism with the tab doing nothing. So I figured that the tab should be located under a corresponding part on the trigger (1027). I relocated it to do that and as the trigger was pressed, the part 1021 rocked with the trigger. Fitting it was trickier but seemed to work.
Next problem was refitting the spring. I had not removed barrel etc as the pins were very tight and I made no impression on them. So how to refit the spring? Unlike deejayvuu, my valve compressor tool was not long enough and was a very awkward fit with the barrel in place. In the end, after about 2 hours puzzling and trying various ways, I set the action in my spring compressor rig, lashed it down and prepared to wind the spring into the piston with the cylinder at a slight angle to allow spring to clear the action. After much trial and error it worked ... a long bolt with about 1cm of thread in the end of the spring guide, stopping on a nut. Winding spring in slowly (goggles and leather glove time), it worked and once I had the guide over the end of the action I managed to slip the edge of the spring guide onto the top of the action and keep it there with a gloved hand while I released tension on the long bolt, removed it and then hand pressure (squeeze) let me slip the guide fully into the recess on the action. Job done. In all about 4.5 hours .....Rifle now works. I can only imagine that in the factory they used various jigs to assemble it.
Was the original jam related to that part 1021 being incorrectly fitted? I do not know as I did not record its position in the jammed state but as it was just too easy to fit it in the wrong position, maybe it was the cause. Maybe the rifle had been apart and put back together incorrectly such that it cocked to engage the abt but not enough to engage the trigger sears... I will never know. But it works now.
Out of interest, the piston washer is 'plastic' of some sort and did feel tight in the cylinder until the last couple of mm when it became looser. With AA Field it gave low 400s. Other pellets that came to hand were not so good, even lighter ones. Given the small compressed air volume I think this is not too bad even though I have read some reports of 600fps achieved after squirting oil into the cylinder.
Hopefully this may, at some time, be useful to others.
Cheers, Phil
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