I assumed the seal was a part of the HB process.
It is not part of the HB itself, but the seal touches the HB and seals the HB hole in the timing cover.
In the image above the seal in question is the black one on the left side.
do yourself a favor and get a haynes or chiltons manual... it has a detailed explanation of how to do this seal...
and FWIW I found it much easier to do the seal with the timing cover off.... it can be a PITA to get the old one out... I wouldn't even try it without the Rad out of there.
as far as the HB goes, remember to pull the washer off before you use the puller, or you will end up like me and just rip your old HB into pieces. :gee:
LOL as many times as I have done that job, I tried to pull it the last time with the washer still on there. I'm really glad I stopped to take second look before it grenaded.:doh:
recently did this on 2 differant jeeps. one wasnt the seal at all... but rather a HOLE in front of the timing cover.
theres no reason to pull the radiator imho, but the front bumper has gotta go. i also pulled the front axle for ease of oil pan re-installation.
when it comes to pullers, i have the common hb puller, and if it was half an inch longer, it wouldnt work, it sits RIIIIGHT up against the inside of the front crossmember steel. i put the round side of a combination wrench (a wratcheting wrench would be awesome, its the only one missing from my set though) over the puller hex head, thread it into the harmonic balancer, then pull it. obviously you dont want to just pull it the whole way with the bolt alone, instead tap the balancer with a hammer constantly, crank it a couple quarter turns, then repeat. think of it like using a pipe cutter.
The time before last I had the bumper off as I was installing OEM tow hooks anyway and had the radiator out for replacement. Jeep day, I was trying to get everything done in the front that needed doing all at one time.I haven't had to remove the bumper to remove the HB or replace the seal. I use the puller/installer from Advance Auto and there is just enough room to get it in there.
To pull on the HB I used a 4 or 5 inch stick of 1/2"-20 threaded rod, since I could not find a long enough bolt that had enough threads to work properly. I used two nuts jammed together at the end as a makeshift bolt head.