[C320-list] ST4000 Autohelm Drive Unit Repair

[Dennis Cookson]

I recently renewed the drive belt on our Raymarine ST4000 Autohelm drive unit, which is a Mk1 version. However, in refitting the cover, which snaps on, one of the internal guide wheel mounts broke off.  I can see this is not an uncommon problem with these units.  I’ve repaired this mount by glueing it back in place, drilling through the casing and fixing with a black stainless bolt, washer and nut, with Loctite added to keep it in place.  I found that a 25mm length button screw mounted with a washer is exactly the right length for the job - there is very little clearance between the rotating parts.

My question is this - should I do the same with all the other guide wheel mounts, or leave them alone?  They all look ok, but so did the one that broke until it did. Anyone done the same fix?

See the photos: 

https://c320.org/mediagallery/media.php?f=0&sort=0&s=20200412144637635 <https://c320.org/mediagallery/media.php?f=0&sort=0&s=20200412144637635>
https://c320.org/mediagallery/media.php?f=0&sort=0&s=20200412144642739 <https://c320.org/mediagallery/media.php?f=0&sort=0&s=20200412144642739>

 <https://c320.org/mediagallery/media.php?f=0&sort=0&s=20200412144637635> <https://c320.org/mediagallery/media.php?f=0&sort=0&s=20200412144637635>Dennis Cookson
Catalina - 0577