So that when I weld the wheel arches in place I get a true line to compare against the door bottoms I’m replacing all 4 front door hinge pins. The doors had only dropped a little from the 40 years of wear, but this movement transferred to the end of the door meant the door bottom scrapped on the arch when you closed it. One of the mirror stalks from the top hinge was welded to the top. This was a quick fix to stop the wear getting to bad, but means I needed to carefully cut off the stalk and grind off the weld to free up the top of the pin. I first tried to squeeze the pins out with a G clamp and small socket hopping the pins would be louse enough to pop out. But quickly gave up to getting the flame thrower out. I’ve been reluctant to attempt this job because of the fear of it turning into a nightmare and ending up damaging the hinges or even worse the doors.
With a fire extinguisher and bottle of water close by and some help from a friend we got the plumbers torch lit and started heating up each hinge. I concentrated the point of the flame only on the upper and lower parts of the hinge as these are the parts that secure the hinge pin in place. After about 3-4 minutes of heat applied evenly on both sides top and bottom, we rested the hinge against a vice and persuaded/eased/whacked the pin out from the lower side. For the first attempt I wasn’t properly prepared, I bent my first punch and lost the heat only getting the pin out half way, The next attempts using a cut down allen key were surprisingly easy, with the pins sliding out and we managed not to scald the doors or burn down the garage.
The next task is to replace the pins and do some thing about the cracks around the hinge rivets. The new upper replacement door mirror arms are 8.5 mm over size, and the lowers are 8mm. my first mistake is presuming the lower pins wont be that worn. The new lower pins slid straight into the hinges and wobbled, so I'll have to replace the 8mm’s to 8.5’s. This had held me up till I can replace these.Some time later...... 
Now with replacement 8.5mm bottom pins and access to a pillar drill I was able to ream the hinges to a tolerance fit. 
This was done with an adjustable reamer, not my first choice but because I was messed about getting the correct size originally this got me through. Adjustable reamers are not the most accurate to use, it took a bit of trial and error to get the exact fit I required, and each pin had a very slight size variation and tapper that effected a tolerance fit.
Now with replacement 8.5mm bottom pins and access to a pillar drill I was able to ream the hinges to a tolerance fit. 
This was done with an adjustable reamer, not my first choice but because I was messed about getting the correct size originally this got me through. Adjustable reamers are not the most accurate to use, it took a bit of trial and error to get the exact fit I required, and each pin had a very slight size variation and tapper that effected a tolerance fit.
