[Fot] Question about Top Hat Bushings

[Robert Lang]

On Thu, 17 Apr 2008, Fridirici, John wrote:

> All,
>
> We break them.

Yep.

> Does anyone know why this happens?

I have theories. Bottom line: the top-hat has a sharp cut and it's very 
likely to crack / shear there. It happens faster if you bang / crunch 
gears, especially 1st to 2nd.

Once that puppy shears, all bets are off because the end-float goes to 
crap and other stuff starts to break or go bad. If you're lucky, you catch 
it before the spacer explodes and you loose the synchro hub, second gear 
and the mainshaft. Not that _I've_ ever done that.

But if you've pumped up your power, you're probably putting in something 
like 50% more input power (and torque) than the stock setup. It's probable 
that you're outside of the designed specs, hence the failures.

> Years ago we made a steel two piece with a brass sleeve. It is now
> broken.

If you have brass on steel, you probably are seeing the brass wear causing 
excessive end-float and then "other collateral problems".

You can get steel top-hats that fit in the old-style second gear mainshaft 
gear, they work pretty good. Just like the late-style TR6 setup (but with 
the older gears that you probably have).

> John Wagner and John Fridirici

Regards,
rml
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