Grob 103 question

We have a G103 with an esa-systems multi function probe. The probe
serves as a static, pitot and total energy ports. The socket that it
plugs into is mounted in the vertical stabilizer and Three tubes run
forward to service flight instruments. The socket contains three o-
rings to keep the three ports separated when the probe is inserted.
These o-rings deteriorate over time of course and allow leakage
between the ports and erroneous instrument readings.

Two of the o-rings are easily replaceable from the front opening. The
third o-ring is small (~1/8" ID) and not so easily replaced as it is
deep in the socket. Wings & Wheels has a nice diagram of the socket
(type UN).

It almost looks to me like you have to dig into the vertical stab and
remove the socket and disassemble it to remove this o-ring, unless
there is a special tool or method to get it out.

Any ideas? Perhaps some of you have traveled this road before.

Thanks.