Rob Fraser wrote:
Thanks Jon,
I totally see a disaster in my future doing this myself. I'm going to
find a repair service in the Chicago area and bite the bullet on this one.
I'll watch and see what he does but I'm going to totally screw this up if I
try it. I might as well replace the timing belt, drive belt, springs, and
any other p/m parts they recommend. This is too big of an investment to
play super-hero on. Thanks a lot for the detailed explanation. I'm noticing
.040 runout on the spindle up top when the quill is fully seated upwards so
I'm going to replace that as well.
Oh, hell, this stuff isn't rocket science (where you get blown
up if anything goes wrong). The Bridgeport J head is really
pretty simple, easy to disassemble and work on, and if you just
take your time and are careful with the heavy pieces, you are
not likely to get in trouble.

..040" runout? Hmm, that could be related, hope you don't have a
bent spindle. Yes, when you have it open, definitely wise to
replace all the wear parts. My head sounded pretty OK, but
looked a bit rough, so I opened it all up anyway. I'm REAL glad
I did, several of the small bearings in the back gear train had
exploded, the ball spacers had broken up and been creamed by the
balls, and there were chunks of the spacers and shields just
laying in the gear train! The plastic bushings in the
vari-speed pulleys should be checked, most likely they will need
to be replaced if the head has a lot of time on it.

There are pins that ride in a cam ring that lifts the driven
pulley assembly to release the direct-drive clutch. (It is
different on the 1J and 2J, but I think they all have this
problem that the pins wallow out the threads in the bearing
housing that goes up and down. So, you want to check if those
pins are wobbly.

You want to check the pipe cleaner-like oil wicks to make sure
they are dripping oil where it is needed.

If the spindle has to come out, your service person will get
that evil gleam in their eye and try to sell you a new spindle
bearing set. Just be sitting on something soft and secure when
he tells you the price! I totally lucked out on the 1J head I
bought to retrofit my round-ram Bridgeport. The bearings had
been changed just before it was packed away for storage. Or, at
least I think that must be the story, as it had that run-in lube
jelly stuff in the bearings. Hopefully these bearings will
outlast me.

Jon