The old ones 'fit' because they have been previously compressed. Seals are designed to conform to the bore they fit in as they are compressed into place, and in the process they intentionally deform. That's why you shouldn't reuse them; used ones lack the ability to forcefully adapt to the surface of the bore. They won't seal tightly and will leak.

New ones never look like they will fit, and it does take patience to start them in properly and to get them seated without bending them.

There are tool kits you can buy which make the job easier/faster, that consist of guides and dies that aid in lining them up and driving them easily, but it's still not guaranteed they'll go right until you get the hang of it.

If you go at it slowly enough, you can even correct for initial misalignment without wrecking a seal. Does take some practice, though.

 

As frustrating as it is to hear, I am glad to see that it is merely my own inexperience at play here. I am glad it's just a matter of getting it done right, and not some incorrect part.

 

Thanks all for the help. My 7 has been happily driving for the past few days, I couldn't have done it without these forums.

 

i was taught to install the seals by putting them on the axle and using the axle as the installation tool. before that i went thru a few seals

 

Yeah for me it was a monstrous socket that I found. Same idea, large, heavy, and exactly the right size.