hey folks,
as you may know the lower guide doesnt come out, or go in because of clearance with the head casing. solution...
to get it out just cut it in half with a cutting wheel, and to put new one on, tuck the upper tip under the headcase, and mate up to the pin, at about 11 oclock. it will be slitly crocked but you will be able to start the pin in the hole easily. dont forget new orings, and to lube the hole. work it on by hand and two medium taps with a hammer and it will pop on. done.