I wouldn't use Stilsons as they are a bit vicious!!
I've recently bought a "proper" tool for £20 from Halfrauds but they can be bought for about a tenner for others (not as nice

) versions.
However, if you use water pump pliers (those that slide up and down to adjust) and a G-clamp to apply pressure it is possible....but as Simon says, only really works if they're not too seized.
If you intend to keep the 155 and possible even go on to a 156 next then I'd advise you purcahse the "proper" tool as 156s are worse!
btw, both sides wind in clockwise
wrinx