At 11:29 PM 8/23/02 -0500, F. J. MacFarlane wrote:
>Anyone have a way to get the @#$#%#@&^@#! 2nd gear brass bushing onto the
>3rd motion shaft in a 3-synchro MGB tranny? .... I heated the blasted
>thing to 400 deg F for 30 minutes, and ....
These are all the same parts as used in the MGA gearbox, and I've never had
a problem with it. The bronze bushings for 2nd/3rd gears are usually
pretty snug on the shaft, but not so's you couldn't encourage them on/off
of the shaft cold, no heating required. The 3rd gear bushing engages the
front spline on the shaft for alignment. Then the two bushings and the
bronze thrust washer all key together in the center to prevent rotation of
these bronze parts on the shaft.
If (when) you are encountering a very tight fit for the 2nd gear bushing on
the shaft, I would say the bore size of the new bushing is too small. Run
a brake cylinder hone in the bushing bore (with plenty of thin oil to
remove the swarf during honing) until it opens up enough to be able to push
it onto the shaft with finger pressure. Anything from moderately high
finger force (light tap fit) to a fairly easy slip fit will be okay, as the
bushing is keyed to prevent rotation on the shaft.
Do be sure to get the radial oil holes all aligned, as oil is fed to these
bushings from inside of the mainshaft. For details on how the gearbox oil
pump works (yes there is such a thing), check here:
http://www.ntsource.com/~barneymg/mgtech/gearbox/gt201.htm
>....
>Also, another question. The 1st gear hub actually slides on the
>mainshaft. There's about 1/4" or so travel fore and aft between the thrust
>washer in front, and the bearing hub in the rear. I'm assuming it's
>normal, since it was doing that when I disassembled the tranny, but it's
>strange, I've never seen another trans do that. What purpose does the
>sliding 1st gear hub serve (not the 1st gear itself, but the hub that is
>splined into the 3rd motion shaft)?
Yes it's normal, and yes it has a purpose which I did have all figured out
once. But it was a long time ago, and I be danged if I can remember
now. At the time I spent a good long while trying to guess where it might
be missing a thrust washer or such, before I finally figured out why it was
actully supposed to be that way. It's the wee small hours of the morning
here (nothing particularly unusual), and my head hurts, so I'll think about
taking the matter up again later.
Barney Gaylord
1958 MGA with an attitude
http://www.ntsource.com/~barneymg
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