>
> > Once I get the car in gear the clutch remains engaged and doesn't
> > slip. This leads me to conclude that the bearing part of the throw-out
> > bearing is no longer functioning and probably doesn't exist :-)
>
> sounds likely. Or, maybe broken fingers on the pressure plate.
>
The original message also mentioned a noise with the clutch released. With
that in mind, I would guess it chewed up the graphite ring.
> > I would like to replace the throw-out bearing with something made from
> > brass instead of graphite.
>
> No you don't- bad move- it would wear out the spring fingers in no time.
> (This is a flat, round ring. The face is the bearing surface, not the
> inside) Later B's did come with a ball bearing version, which you can use
> instead. Racers still prefer the graphite item tho.
>
Ummm sorry, but MGB's had the graphite bearing right up to the last wheeze,
1980. There was an aftermarket ball bearing replacement available in the
late 70's and early 80's (is it still made?). These didn't work too well, due
to the design of the MGB clutch linkage. The B constantly drags the throwout
bearing against the face of the pressure plate, just like disc brakes
constantly lightly drag the pad against the rotor. Not a big deal normally,
but these aftermarket bearings didn't cope with constantly spinning very well.
The graphite bearing is usually good for 70-80K miles with pristine driving
habits, and maybe 10K if you always ride the clutch. The ball bearings seemed
to last about 40K no matter how you drove it. :>
>
> > 2. My transmission has the larger layshaft axel with more bearings which
> > I would like to keep as well.
>
> ??? I'm not sure I know of what you speak there...
There was a change in late 66 or early 67 to the 5-main three-sycro box.
Among other things, BMC upped the layshaft size, and put a second set of
rollers at the first gear end in an attempt to get that bearing to live.
'em new monster 18GB's were dumping way too much torque in for those puny
little bearings to handle, ya see.
In the parameters being discussed (5-main, 3-syncro, o/d), there are two
boxs. The one used in 65 and most/all 66 has the small layshaft and bearings.
The one used in 67 has the big ones. If buying an exchange rebuilt unit, you
have roughly 2 to 1 odds against getting the good one. And the only way I
know of to tell them apart is to remove the front cover and measure the
layshaft diameter. Do note that the 2 to 1 above is not really correct. More
67's were built than 65's or 66's. And, it is possible to fit the later
shaft to the earlier box by replacing all of the affected components, and
boring out the holes in the case. This was done quite often, too. For about
five years or so, the early gear was NLA. If you were rebuilding, you *had*
to convert it to the later style.
Randy
randy@taylor.wyvern.com
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