Raymarine ST60 wind transducer refurb. problem, with photo

I replaced the bearings by cutting a 4mm slot and a 3mm slot in a piece of 2mm steel plate. 2mm is thin enough to fit within the neck on the shaft. Using the correct size slot, 4mm to press off the bearings and 3mm to press on, it's easy enough to squeeze the shaft in the jaws of the vice with a suitable socket bearing against the plate. This gently pushes off the old bearings. No hammering required. :)

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The new bearings can be squeezed on using a reverse process but they were a bit looser on the shaft than the old bearing so could gently be tapped into place using a 4mm socket. The 3mm slot steel in the vice supports the shaft at the collar whilst you tap in.

This is the shaft with the new bearings in place. I did a bit more adjustment after this so that the collar is only just visible at the extreme left and right. This allows the assembly to sit easily in the white bearing holder. This side is now fully assembled. I now have to do the other pair but it will be the repeat procedure.

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Next I will be replacing the circuit board and then bench testing.

Richard
 
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The new circuit board is now clipped in and here is the re-assembled MHU with the old circuit board and old bearings, totally undamaged as no hammering was needed to press them off the shafts. The new bearings do feel slightly tighter to spin, presumably because they are still full of grease, but I don't think there is anything actually wrong with the old ones. However, after 10 years continuous spinning, it's probably worth changing them for the sake of £10.

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Finally, the test trace.

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This time it looks like two sine waves offset by 90 degrees so I now have a spare. :)

Richard
 
RichardS said:
I'm beginning to understand why I have been unable to find a single strip-down walk-through for the updated ST60 wind MHU .... it's not exactly intuitive.

I've hit some problems but here is progress to date:

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The above photo shows the two halves of the central "egg" housing. The two parts simply unscrew by hand and there is an O-ring which provides weather sealing. I have removed the rubber cap which covers the wind direction magnet. It simply pulls off. On the wind speed side you can see the speed sensor disk, but more of that later.

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The above shows the other side of the central housing. The white thing is a split bearing carrier which needs to be pushed out. It comes out in the direction shown in the photo.

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Above is the first problem on the wind speed side. This sensor disk needs to come off and is a push on the end of the shaft according to Cris. However, it's a very thin plastic disk and it's on very tight such that I can feel it flexing when I grip the sides and try to pull it. I'm worried that if I pull any harder it will just shatter. What I really need is some way of pushing it out from the inside close to the shaft but that's a tall order.

I've tried just pulling the other metal end of the shaft out with the bearing housing from the other side in the hope that this would also force off the sensor disk but I can't get it to move in the vice.

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Now, this side is simple. I used the workshop vice with a socket over the bearing carrier end (13mm or something) and held a small 6mm bolt so it was pressing against the magnet and squeezed the whole assembly. The bearing carries just slides out easily. :)

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Slide off the two O-rings using a pin and slide a fingernail into the split in the carrier and it falls apart.

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But that leads to the next problem .... the bearings. Here you can see the ones I bought .... 3mm internal x 8mm external x 4mm wide. According to all the references I could find on the web, these are the correct bearings. However, Raymarine must have changed them for the new MHU.

I've measured the bearings on the shaft and they are 4mm internal x 8mm external x 3mm wide. A small difference but crucial. These are also a much more unusual size although they do have one stainless version at Simply Bearings so I'll have to see if they will exchange mine.

It's not really clear to me which end the bearings have to be pushed off and whether they will slide over the central section covered by the spring. I thought at first that it was a larger central collar but it is 4mm which is the same as the other larger sections of the shaft. The thinner sections which are located in the bearing carrier are 3mm but the bearings will have to go past 4mm whichever way you go. There is a 4mm collar hidden under the O-rings.

So, there we are. Two steps forward and one step back.

Any advice about the removal of that sensor disk or advice about the direction of pressing off the bearings would be most helpful. In the meantime, I'll see if I can change the bearings.

Richard
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I know that RichardS moved on some time ago and I was hoping that his write up of changing the bearings on his ST60 vane would help me with my problem.

My ST60 MHU ( not sure if earlier or later model) cups have stopped rotating, even in a gale. Does anyone know how to get Richard's write up back from the dead, or offer any advice on how I get my cups moving again?

Cheers
Donald
 
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Aja said:
I know that RichardS moved on some time ago and I was hoping that his write up of changing the bearings on his ST60 vane would help me with my problem.

My ST60 MHU ( not sure if earlier or later model) cups have stopped rotating, even in a gale. Does anyone know how to get Richard's write up back from the dead, or offer any advice on how I get my cups moving again?

Cheers
Donald
Click to expand...
ST60 60 new version and same situation here. Cups stopped rotating and I can see the oxidated axe. Still have to find a way to put off the black disk inside the “egg” then (if success) I try to hammer somehow the white plastic cilindro from the inside to outside … then we’ll see…
Any help much appreciated
 
RichardS said:
Simply Bearings have happily agreed to swap my unused 3 x 8 x 4 bearings for 4 x 8 x 3 versions. Once those arrive I'll be starting on bearing removal. :)

Richard
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I’m at the start of this journey - how do I get access to the bearings? I haven’t managed to unscrew the top of the egg, which I assume is necessary to get to the bearings?
any useful advice and photos would be really appreciated.
 
I think I used a rubber belt device intended for removing screwed bottle tops to grip one half of the "egg" and a vice (very gently and with rubber padding) to hold the other half and whilst stiff, it moved and unscrewed.
 
Aja said:
I know that RichardS moved on some time ago and I was hoping that his write up of changing the bearings on his ST60 vane would help me with my problem.

My ST60 MHU ( not sure if earlier or later model) cups have stopped rotating, even in a gale. Does anyone know how to get Richard's write up back from the dead, or offer any advice on how I get my cups moving again?

Cheers
Donald
Click to expand...
Do not know if you have been heard earlier, but why not try this https://www.hisse-et-oh.com/store/medias/sailing/5dd/28a/653/original/5dd28a6539819f3668e5f949.pdf
 
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