[Leica] M3 slow speeds adjustment by a user ?

[alex at zabrovsky.com (Alex)]

Just got back two beater M3 bodies from a CLA/repair by a well reputed 
repairmen in US. Both needed quite extensive treatment to revive them, 
including replacing shutter curtains on one of them, chasis on the 
another one, some small bits and odds here and there, external cover, 
etc..., both cameras where totally non-operative.
Now, the film advance feels really smooth on both, probably even 
slightly smoother then on my M6 (which operates just fine) and overall 
both were treated with great care, however one of them exhibits shutter 
speeds issue on slower speeds. Speeds of 1/8 and slower appear to get 
stuck on approx. 1/8 setting, I can't see any observable difference (by 
my ear and visual judgement) between 1/8 and 1/4, 1/2 appears to be just 
a tad slower then 1/8 and 1 second appears to be similar to that also. I 
compared these with identical settign on the second M3 and my M6 - there 
is very obvious and clear difference in slow speeds.

I contacted already the repairmen seecking his advise, now waiting for 
him to respond. On the other hand, shipping it back sounds quite 
combersome involving overseas shipment back and forth, Customs hassles, 
lots of wasted time in shipments, etc...I'd like to explore the 
possibility of user adjustment of slow speeds.
I'd like to hear and opinions as to whether you think those speeds can 
be adjusted by the user (bearing reasonable technically-inclined 
person). Does it involve any complex camera disassambly ? Any special 
tools ? Special shutter speeds meter ? (Can I adjust to approx. what I 
can fetch by visual/sound estimation of M6 and other M3 ?)

Thanks in advance, Alex