Spring issues

[etd]

I installed a sorbo pad and a metal spring guide with bears along with a new m120 spring in my sig 552. The spring is much longer than my stock spring and I believe its causing problems. The piston won't push all the way back when firing now. Did I purchase the wrong spring?

[CDN_Stalker]

Likely the Sorbo pad is pressing the piston back a bit too far, and the sector gear is grabbing the second tooth instead of the first, causing this issue. Check out your spring guide too, if the length is too long, it could add to the problem. Best to try one new part at a time to localize the problem.

[Cushak]

+1 to CDN_Stalker's diagnosis.

Because of the Sorbo pad's thickness, it can cause the piston's "at rest" position to be to far back, causing a misaligned of teeth between the piston and sector gear. A fix for this is simply to remove the second tooth on the piston (and possibly shave the third tooth down to half).

Also, I've had spring guides on which the ball bearing's outer diameter was the same or greater than the inner diameter of the piston, and the spring guide would stop rear-word motion of the piston, causing a seize. Simply take an exacto knife and drag it around in circles on the inside of the piston at the rear, to make it "fluted" a bit.

(And spring length shouldn't be a problem unless it's too powerful a spring fand requires more torque than your gear/motor combination can provide)

[lemegacool]

if you want to know if the spring is too long... try to fully compress the spring with the spring guide by hand into the piston... the spring guide tabs should toutch the back of the piston...

[CDN_Stalker]

I just recalled an incident like this where I used the client's Deep Fire bearing spring guide and titanium tooth piston, everything worked great using the psiton and stock spring guide, but would lock up when using the DF bearing spring guide. Royal pain in the arse, but still better and easier to deal with than solving air seal issues.