Closing the loop on my shaft brake project

thomas.kleman <no_reply@...>

Hi folks- wanted to close the loop on my recent shaft brake failure and fix in the hopes that it helps 1 person.......

In short, while sailing I heard the tell-tale grind and quickly figured out my prop was still turning; we were moving over 8 knots. I trolled through the group site and found some interesting tidbits.

The max extension from the shaft brake housing to the edge of the "finger" is 60 mm (per the Amel mechanical drawing). If your unit extends that far with the engine off, it's out as far as it will go no matter the adjustment tension on the spring.

I ordered the pads from Amel and inspected them; to my disappointment, they looked (to the naked eye) similar in thickness to the old ones (which weren't holding). Hmmm. I also changed the spring (the old one had compressed slightly, but as I note above it wasn't important due to the 60 mm extension of the finger.

So I mounted the new pads, installed the new spring, cleaned everything really thoroughly with brake cleaner and presto- it seems to work fine. My takeaway.........the whole system (when the shaft brake is activated by the stopping of the engine) has really close tolerances.......I would have preferred to have been able to adjust things and use more of the pad before replacing it. The setup does prevent you ever grinding your rotor with worn-out pads, so I guess that's what was intended there. So if you have an SM2K older than 422, you might consider making sure you have the pads.

My emergency plan (should I need it) is still the suggestion Alan Leslie put forth in the original discussion; solving the 60 mm finger extension issue by mounting an adjustable screw directly on the spot where the finger compresses the caliper. That's where I was heading if my new pads and new spring didn't do the trick.

Hope this helps.

Tom Kleman


SM2K # 422

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