RayMarine ST4000+ Autopilot Fixed

[pfaffk]

Yesterday I posted regarding my RayMarine ST4000+ Autopilot breaking. Early this morning I bought some SS bolts, drilled three hold to thru bolt the broken wheels, and surprisingly it was a very easy fix. I reassembled the unit, and then discovered that indeed the clutch lever was not working correctly. Took it apart again and figured out that the sheer pin was sheered off and that the clutch lever would free spin. Pull the lever off, use a small finishing nail to knock out the pins then used the metal handle off of one of those black metal spring clamps that you use to hold papers together, cut it to size, and put the clutch lever back together and reassembled the unit. I just got back from a test sail and it seems to work perfectly. The wheel was very stiff at first but seemed to loosen up after turning the wheel back and forth for a minute or two. I will have to see if my makeshift sheer pin lasts or not as I feel that is the week point in my repair, but at least for now I saved spending big bucks on either a replacement or a totally new autopilot

 

[kloudie1]

Good repair .. The little clip handle is probably chromed carbon steel so it will corrode and make a mess slowly ..ya probably can get a couple of years from it, more if you coat it with a grease to keep any water off it..

 

[jviss]

Good job! I encourage putting a real shear pin in, as if the shear pin doesn't shear when something jams, other parts may break.

 

[smokey73]

Good job! I had both of those same problems. I used a small stainless steel finishing nail (can't remember the size right now), cut to length, to replace the shear pin. While it wasn't a "certified" shear pin, I figured that the strength (maybe wrongly by the way) of the stainless steel would be less than that of a carbon steel nail of the same size. I have observed that when cutting nails, the stainless steel of the same size seemed to cut easier, thus my assumption. I also cut several extra's in case I needed them in a pinch and put them in a bag in the Nav Table. Maybe a Metalurgical Engineer can chime in on the relative shear strength of stainless vs carbon steel? I can't find my Mark's Handbook right now!

Of course you can probably source a real shear pin which would put any questions to rest.

 

[jviss]

A shear pin is much, much softer than a steel nail of any kind. Usually aluminum, and hollow. Think of it as a mechanical fuse. Using a nail is like putting a penny under a screw-in fuse because it keeps blowing! Your nail won't fail, some more expensive part of the system will break.

If you can't get a replacement shear pin, get a piece of aluminum tubing that fits.

You might also go to the Raymarine support forum: http://forum.raymarine.com/index.php

 

[smokey73]

Great idea jvss. If I recall correctly, the original shear pin was solid but may have very well been aluminum rather than Stainless Steel. It was solid and non-magnetic for sure. Getting the original as designed is the best bet but an aluminum finishing nail might do in a pinch. Even if its too weak rather than too strong at least it would fail before doing damage to the rest of the equipment. I'm not sure you could source Al tubing small enough.

 

[jviss]

What diameter do you need?

 

[jviss]

You know, it could be that they are not shear pins at all, but just roll pins. Again, try to measure the diameter and length.

 

[pateco]

Sunday morning as I was preparing to pull up anchor and head home after our club's Oktoberfest cruise, I noticed the steering was stiff, and there was a small piece of wire jutting out from the gap in the Auto-helm ring. I decided to investigate. I removed the whole wheel and ring, and below is what I found.



Now that belt disintegrated LOL. I have ordered the replacement MK1 belt, and it should be here Thursday.

I can say that the steering felt a whole lot lighter without the Auto-helm attached.





How many seasons do these belts normally last? Should I buy a Spare?