Replacing and Installing spark plug tube seals on the 1mzfe, a tutorial..
After hours of frustrating seaches on google for how to deal with the PITA tube seals on the Toyota 1mzfe engine, I will share my new found knowledge for anyone stuck in the same nightmare scenario.
The primary issue with these suckers is that fact that they will likely be so degraded and literally melded to the metal walls of the valve cover that you will nearly go insane trying to figure it out.
After removing the valve cover, DO NOT make the mistake I did and start trying to scrape off to interior of the tube wall thinking you will get anywhere -- you won't. Here's the trick, leverage. Be aware that the tube seals are rubber flexible material in the middle, but are reinforced with steel around the outer edge even though they look like hard rubber/plastic -- they were probably installed with a massive press with extreme force from the factory, so they are now nearly fused with the valve cover.
The best tool I found was a tire tool that has the flat bladed end on it, they are an OEM tool with many cars - if you don't have one, then you will need a heavy duty long flat headed screw driver. With the valve cover upside down, look carefully in the tube holes and you will see a slight gap at the very bottom of the hole that my well look like metal that's part of the valve cover. It isn't. Wedge your flat blade at an angle up under this gap (you may have to hammer it in to get it to grab up under the metal) and then strong-arm your tool downward - lean into it and then let off a bit and repeat, sort of getting a torque effect. The metal ring will eventually dislodge from the tube holes, and voila, you have removed the tube seals.
Clean out the tube holes as well as you can , and get ready for the fun part. You will also notice some little metal tabs at the edge of each side of the tube holes, I'd suggest bending those upward as it helps a ton in keeping the new tube seals in place in order to press them in. Place a new tube seal in the hole (the orientation of the new seals will be raised edge up where as you could insert a 30mm socket into them, which is one way to beat them in). I used a 33 mm socket, which would be a standard axle spindle nut socket - if you don't have one then you will have to improvise with a piece of wood and go from there to get them as far in the holes as you can. Place the socket open side down lined up with edge of the ridge of the new seals - get a solid piece of wood (so you don't break your sockets), place it firmly onto the top of said socket, take your hammer and beat it as hard as you can with precisive blows to keep the pressure as even as you can -- don't hold back, these suckers take massive force to get them pressed in correctly. If you are worried about leakage, then coat the seals with high temp RTV before installing and around the top edge after they've been beaten in. That's it!!! Enjoy!