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PostPosted: Mon Nov 01, 2010 7:32 pm 
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Like bone loss and senility for humans, loose and worn out Aka joints are going to effect all hinge-pinned AI's at some point, if they live long enough.

As the bars are repeatedly stressed, many owners experience enlarged/elongated holes on the Aka and crossbars. It's a contest of aluminum vs steel, which the locking pin always wins.

The fit becomes sloppier and noisier as more aluminum is worn away. Eventually, your AI's knees are knocking and flexing in very unsettling ways out in the waves. Your locking pins may even start to walk out of their holes in rough conditions. Mine have. A scary sight.

If wobbly joints have become an issue on your AI, what measures, (other than a total hip replacement) have you tried to fix it?

Redrilling? Inserts? Welding? Different pins?

Please share any treatments that have or have not worked. Photos appreciated.

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PostPosted: Mon Nov 01, 2010 8:32 pm 
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Nohuhu,

My TI is too new to experience the same. But it does bring up the question if the new aka "knuckles" are serviceable parts. Looks like they attach to the aka's by some sort of alluminum rivet. And so one could possibly drill it out to replace a knuckle assembly.

Can't think of a good way to service the previous pressed/hinged style joint. It just seems filling the gap with a spacer or epoxy fill will just add additional stress to an already worn area.

I wonder if it would be possible to just cut the old joint off and rivet on the new "knuckle" version. But you still have to replace the crossmember.

Just throwing out a few bits...

cliff2yak


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PostPosted: Mon Nov 01, 2010 8:44 pm 
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I just add padding (small pieces of indoor/outdoor carpeting) where the aka joins the aka x-brace and the noise stops. Also they seem to wear only so far and then stop. Has anyone had a aka x-brace (or aka) wear out?

Here's two old posts on this:
http://www.hobiecat.com/forums/viewtopic.php?f=69&t=17674&

http://www.hobiecat.com/forums/viewtopic.php?f=75&t=9418&

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PostPosted: Mon Nov 01, 2010 11:17 pm 
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reconlon wrote:

And another one from Slaughter:
viewtopic.php?f=75&t=13167&p=75628

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PostPosted: Tue Nov 02, 2010 8:36 pm 
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Nohuhu,

My advice is coming from having to break a few tie rod joints back in my 4x4 days. Any rattling or loose joints should be attended to or breakdown deep into the trail. Advice from the like of recolon who frequent (looks forward to) marginal sea conditions is golden. My suggestion was out there and kind of extreme considering the application.


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PostPosted: Wed Nov 03, 2010 3:22 am 
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I like slaughters rubber pads. This type of shim is one approach I have not tried yet.

When my Akas first started banging around in the waves, I started thinking about redrilling the holes and going to a larger pin, or heating, pounding and reshaping the pins. All would lead to more eventual wear and repairs.

Another problem with tightening the joint is the difficulty you have inserting or removing the pins, (until they wear again). So it's a mixed blessing.

Some of my friends arrived at a cool solution. They drilled out the holes a bit and replaced the stainless pins with a narrower one, fitted with a plastic sleeve (think durable fuel line material). The sleeve provides a snug, cushioned fit and sacrifices itself over time. It's easily replaceable. I'll get picts for you if possible but I think I described it clearly.

Originally I just wanted to stop the wobble and took a simple approach. I simply tied a loop or two of 50lb test line inside the Aka holes. This stopped the excessive top and bottom play that translated into wobble. But it only lasts a couple sails. Still - it's invisible, dirt cheap and easy, so try this if you need a quick fix.

You can use thin but tough black tie wraps as well. They last a little longer.

This cured the noise but the locking pin still wanted to launch into orbit during a hard sail. To treat this, I also replaced the worn bungees that hold the pins in place. The are shorter and much tighter now but still don't hold the pins 100% so I added snug bungee wraps around the bar which I pull directly over the pins to exert downward force. This holds everything in place now nicely, with or without the tramps deployed. Together with the double bungees holding the Amas on, I have a lot more confidence in the AI's decrepit joints now.

I think a more permanent fix will be the pin and sleeve method, but I'm first going to try applications of cold JB weld or quicksteel aluminum to fill and ream the holes back to spec. The rubber bushing (or pads) would be a nice complement to this, I think.

I all fails, we have a metal worker in the hui that can perform proper heat welds.

Please let me know what you think of these ideas and share any that you think would work better.

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PostPosted: Thu Nov 04, 2010 12:55 am 
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NOHUHU wrote:
The fit becomes sloppier and noisier as more aluminum is worn away. Eventually, your AI's knees are knocking and flexing in very unsettling ways out in the waves. Your locking pins may even start to walk out of their holes in rough conditions. Mine have. A scary sight.

Gotta say that your post really caught my eye. From looking at the AI before we went with the TI, I wondered if the AI hinge would do as you describe over time.

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PostPosted: Wed Nov 10, 2010 2:29 am 
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whosyerbob,

Like any mechanical joints, the new knuckle joints will probably wear over time. I'm hoping the new design will extend the time before you have to service it.

I wonder if Hobie will sell you just the knuckle assembly that you can re-rivet back onto an aka bar? Maybe too soon to ask.

cliffs2yak


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PostPosted: Wed Nov 10, 2010 4:53 pm 
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I saw caking on a TI Aka that looked like Aluminum oxide (Al2O3) was forming inside the knuckle assembly.

Has anyone witnessed this or any other corrosion on the new Aka hardware?

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PostPosted: Thu Nov 11, 2010 1:46 am 
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Good thread Nohuhu. After doing any modification to the AI I usually like to get in a dozen sails before I make a comment, but with the mod I made to the ama connection, I couldn't wait to share it. viewtopic.php?f=75&t=13167&p=75628 (thanks Chris for attaching it earier) I've had the rubber insert mod in place now for well over a year and the play and wear in the joint hasn't changed at all. I reckon rokraiders is a better mod though if you have access to maching facilities.
What I also do though is spray WD40, or equivalent, on the pin every so often to not only help get the pin easily through the hole, but to reduce the friction, and thus wear, at the joint.

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