Go to the site I gave you
You take the piston assem out and push the pin all the way through and out,,,then re-enter it in from the front .
It can only go foward b/c it has a ratchet lock .. so it can never release.. if you do not puish it through and re-enter , it will be too long and put too much pressure on the chain...
I do not think you arte taking the whole umit out.