Datsun Roadster Forum-311s.org

Ok. Been trying to get the rotted freeze plugs and coolant nipples out of my intake today but keep getting scared I'm gonna break something. Anyone got any advice or suggestions? I have it soaking in diesel in the parts washer for the night hoping that might help but need guidance incase that doesn't do it.

The small 3/4 " type ?
Those I've done by drilling the bottom out completely ,with same size bit to then take a hack saw blade and saw into the side until it's loose
bigger sizes , a deep tread/ pitch 1/4" concrete screw drill a 1/8" hole off center get it in usually they will work with a slide hammer and hammer it ,it will turn sideways the grab with pliers
Another trick ,works good on bearings too is
Drill a 5/16" hole in the bottom of the plug ,get a 2-2.5" long fine thread bolt grind the head of the bolt round just enough to go thru the drilled hole and grind a bit off the shaft by the head ,
Put the rounded off hex head thru then to the side and jam it with a clothes pin wedge ,nail ,etc so the bolt is trapped then put a .5 " drive socket large eng facing the plug to remove
Then washer and nut and tighten the nut
Visegrip the end of the bolt if it spins

I don't have a slide hammer unfortunately. Might pick one up today. I usually just drill a hole big enough to get a screwdriver in it and then pry them out, but these are a little small for that. The hacksaw blade idea is good, I'll try that today.

The screw in hose nipples on the end are what really scare me. I've tried heat but to no avail. I'm worried if I keep trying to pry on it I'm gonna end up marring up the intake. I've been wrapping it in shop towels and clamping it in the vise to avoid this, but I'm scared to clamp it to tight and bust the casting.

I think you might want to try a hook seal puller, also warm it up and see it helps. The SU manifolds are very common so it doesn’t matter if you hurt it, so go mid evil on it.
Dave