JaniH

Finally found good used bravo xr with -2 sportmaster, the the drive is opened and serviced recently, but it is done by the mercruiser book, so no tricks/mods. Going to get the upper rebuild during next winter, the upper case is going to be shimmed instead the preload metod. Have heard that the stock clutch shaft is the weak point and should be replaced with aftermarket shaft, so who makes the best clutch shaft and what needs to be done to make it fit?

snapmorgan

Either IMCO or Max Machine Works. Clutch shaft is a direct replacement, no mods necessary.

JaniH

I Have sent email to max machine few times but they never answear. The imco sc shafts price seems reasonable. Thank!

larose481

Or the Teague Platinum XR shafts. What do you mean shimmed vs preload? Upper gears have no preload, just race thickness to adjust backlash and the input bearing uses torque for the preload and a shim for the pinion depth.

JaayTeee

Hard shimming the pinion bearings….. Bravo shop has shims they sell that go
between the 2 pinion bearings, you shim as needed to get the rolling resistance and torque the nut down( too many shim, not enough preload,
too little, too much preload, seemed like it took around .075” to get it right.

The factory just tightens the nut down til the proper preload is reached,
and you’re hoping that elastic nut holds, once bearings loosen up, or the nut,
the washer on the input shaft will spin and start “machining” itself against the
input shaft, loosening things up more, when you hard shim it, that can’t happen, since the bearings, shims and washer are all squeezed together.

bencini231

I had the same luck with emails. I started calling instead and they answer every time.

larose481

Correct. Sorry read the original post wrong.