yeah, they are pretty large holes, and its not fun!
i will have to try that cardboard sheild idea. i wear my long sleeve shop shirt, Ingersoll Rand mechanics gloves, a face shield, safety glasses, my baseball cap, and ear plugs. the ear plugs are more to keep hot metal shavings out of my ears!
We only have to drill holes if we cant put a hole in it with a hammer first
the first hole that we all drill is on the right rear corner if looking at it from underneath. right where the subframe angles up towards the rear mount/control are pivot bolt. on that angle, there is another piece of steel lap welded on the outside edge. we drill just inside that lap weld. same for the other side
the front to holes are right where the subframe flattens out after the angle from the front mounting bolts. the passenger side has a hole from the factory, about 1/2"-5/8" in diameter. we drill right next to that.
Hyundai supplies a cheapo guage made out of 16 guage steel, with 2 slots cut into it to measure the thickness. very accurate
they also supply us with a 1 quart siphon feed spray gun with a hose attatched for spraying the wax inside the holes, after we blow all the loose rust out.
And yes, it is a much better job to replace them, at least i feel it is. its very simple after you have done a few. here is a list that i can think of off the top of my head. remember, if its getting replaced, that means its rusty!!! and, air tools are a must!
first, take off the airbox lid/intake tube assembly, removing the one hose near the throttle body. its not necessary to disconnect the MAF sensor, but it will give you more room. then with aleast 18-24 inches of 3/8" drive extensions, and a 14mm universal joint socket, remove the three rear motor mount (roll stopper) bolts.
next move to the pass front corner, and remove the 2 10mm power steering line bolts. one is in the very front corner, and the other is under the pass side motor mount.
raise vehicle up as high a possible, preferably on a lift. remove wheels. tie a large zip tie around the inner tie rod, and around the brake line bracket on the body. this will stop the rack and pinion from falling out at a later time.
remove 2 17mm bolts on for each ball joint, and remove 17mm nut and through bolt on strut "wishbone".
remove 14mm through bolt and 17mm nut on front motor mount (roll stopper) (1999 model year sonatas must have a new roll stopper installed. there is a special part number for it, ending with QQH)
now you will be able to rock the motor back and forth by hand since the 2 side mounts up top are still connected. now, wrap a reliable ratchet strap around the pass side axle at the transmission, and to the front tow loop on the subframe. tighten the strap until the motor stops rocking forward. this will give you plenty of room to reach behind the motor to remove the 4 17mm p/s rack bolts. note that the 2 longer bolts go on the drivers side!
now that the rack is loose, and supported by the zip ties, and column shaft, you can remove the ratchet strap.
now remove the 2 17mm nuts, and 4 14mm bolts that hold on the 2 triangular support brackets on the rear mounts of the subframe.
there is one more p/s line clamp bolt to remove now, and an air ratchet and 10mm swivvel socket work perfect. its on the pass side towards the rear, just behind the axle.
now comes the fun part!
what we have are a couple high lift transmission jacks with 2 4' 2x4s across it. put this under the middle of the subframe, and put a little pressure on it.
only 6 bolts left...
remove the 2 17mm front subframe mounting bolts.
remove the 2 19mm rear mount bolts (with a stud on it, that you previously removed a 17mm nut and support bracket from)
next are the 2 that almost always fight us. behind the strut, there the 2 final subframe mounts. these are 2 17mm nuts, and large washers (one on each side) luckily Hyundai was smart enough to put holes in the lower control arms so that you can put a 17mm socket and extension up through to remove the nuts
now, slowly lower the subframe about 3 inches. At the top rear, there is one more bracket that holds the p/s lines to the subframe. another 10mm bolt there. remove it.
now the subframe, lower control arms, sway bar, and front motor mount can come straight down.
remove 2 14mm bolts on front motor mount.
remove 4 14mm bolts on sway bar bushings.
remove 4 17mm bolt on the control arms, saving the aluminum spacer on the rear of the 2 bolts.
remove the 2 22mm bolts at the control arms rear pivot points
take off control arms and swaybar as an assembly, so that you or your shop dont have to buy new sway bar endlinks!
take off all 6 rubber insulators at the mounting points.
now, installation is the opposite of removal.
a good set or torches and the skills to go along with them will help you out alot, but they can be very dangerous. thats where the miniductor somes in. check it out: http://www.theinductor.com/index.php?m=41
there arent many special tools that you need, but air tools, and swivvel sockets are a must. also everything is metric.
i dont think i forgot anything, but im sorry if i did. i hope this helps at least one person. hell, it took me as long to type this as it takes me to replace a subframe!!!