There are certain fasteners that, for the life of me, I can’t figure out how the factory installed in any kind of timely fashion. Some that come to mind are the two bolts holding the heater valve to the block on an MGB. Luckily, there are special tools that make the job a snap. A U-joint socket is simply a socket, with a built-in universal joint.. They are superior to a socket-and-U-joint combination because they are extremely compact. I have a pair of then, both made by Snap-On, in ¼”drive, a 7/16” and a 1/2”. The small one is useful for lots of things besides the heater valve, since there are so many ¼” bolts on our LBCs. The ½” one is perfect for speeding up the removal and installation of driveshaft bolts and transmission mount bolts. It is also great for sneaking past the radiator to remove the rear bolt on B steering racks, without removing the radiator. They may not be the most-used tool I own, but it sure does make me happy when I get to use them, and I think about how annoying those little jobs used to be.
I recently added the 1/2"-drive 3/4" socket for removing MGB sub-frame nuts, right through the access hole. It goes on a 6" extension with my big, scary, 1/2" impact driver and really gets the job done, even on those where the post is slightly loose. With a manual rig, the assembly will just spin and spin, requiring a helper to hold things up top, or jamming a wrench on the upper nut and hoping it will stay while you crawl back underneath. The impact rig will take the nut off, overcoming the inertia of the nut while leaving the post bolt to rattle in place. Nice.