Autopilot wheel drive repair

[PlaneTom]

Our autopilot wheel drive began disengaging itself, first occasionally then more often. I had replaced the clutch and the idler wheel maybe six years ago. When I removed the wheel drive I found the backing plate broken. On the back of the plastic plate there is a metal plate that supports the end of the gearbox, clutch wheel and idler shafts, and the mounts for that were broken.
I found the part number for just the backing plate, but at a price that seemed high, about $170 as I remember. I called Raymarine to see if they sold the part, and they told me they have a flat rate repair for the whole unit (P/N A18081) at $315 plus tax and shipping. Since the rest of the unit including the motor has likely been on the boat since built in 2000, I figured there were likely more worn parts so I shipped it to them.
They received it on Oct 7, it showed up at my door yesterday, Nov 2.
They replaced the broken back plate, the belt, and the gearbox.
If the weather behaves tomorrow I'll remount it and take it out for a test.

 

[Project_Mayhem]

Thank you for posting this. It's good to know that there's reasonable repair options available

 

[PlaneTom]

The person I originally talked to at the repair center was very helpful. But getting updates on the status of the repair once they received it was difficult to impossible. They received the part on Oct 7, and the estimate was 7 - 10 business days to complete. Late in the month, when I went on their website to the section for checking repair status, it just listed it as "Submitted". I called, and got no further information.
On Nov 2, the website still just said "Submitted", and suggested an email inquiry to get more info. I sent the email and asked for a projected completion date. Later that day I got an email reply that just said "We'll contact you when it's complete".
2 hours later it was delivered to my house. The packing list was filled out and dated Oct 23.

The price was good, I'll get it back on the boat and tested today or tomorrow, but the communications were not so good.

 

[jssailem]

It's unclear which wheel pilot you mean.
Around 2000-2001, Raymarine was transitioning from the Raytheon/Autohelm era.

• The Mk1 ST4000 is often identified as an AUTOHELM product.
• Or the Mk2 drive unit (grey housing, part E12093)

Mk1 ST4000 used a black drive ring and was more prone to certain mechanical issues; the Mk2 improved that while keeping compatibility with the control head and compass in many cases. Instruction and parts manuals are dated 2001 for the Mk2 drive unit. You said your boat came equipped in 2000.

Here is a parts image of the Mk2 unit

Parts for the MK2 units are easier to find.

 

[PlaneTom]

OK, mine is a grey plastic unit, and the parts list I found, in the attached manual page 6, showed P/N A18081 as the entire wheel drive assembly. This is also the P/N on the packing list for the repaired unit, which it listed as a ST4000 MK2 Wheel Drive Module.
What I found broken on mine was item 24, the back cover. The studs that mount item 3, the support plate, were broken.
They replaced that back cover, the belt, and the gearbox item 23.
It's back on the boat, I hope to go out tomorrow and try it out.

 

[jssailem]

I would be excited. It will likely serve you well.
If you can access the parts, the unit is very serviceable.

 

[PlaneTom]

I would be excited. It will likely serve you well.
If you can access the parts, the unit is very serviceable.

True, but some of the parts may be harder than others. When I found the broken back plate and got a part number, I only found one place that even claimed to have it. I tried contacting them to confirm availability, no luck. Knowing that at least the belt also needed changing, and once I found out that Raymarine would go through the entire assembly for $315, the parts cost of the parts I knew needed replacing could easily exceed that. And I likely would not have spotted the worn gearbox, that wasn't apparent.
A similar situation to 5 or 6 years ago, the roller furling on the jib was getting very tight, I sometimes had to put the furling line on a winch. I opened the drum unit and found bad bearings in a corroded drum. I was trying to find the best way to remove the bearings without destroying what was left of the aluminum drum, and I called Schaefer to ask them. She asked "What do you want to change those bearings for??" Because they're shot and I can't furl the sail! It turns out that they sold the drum assembly with new bearings for $250, and it was the updated version with two holes in the drum to flush fresh water through it. My old drum did not have those.
Replacing it took a few hours, 2 or 3. Remove the sail, tie the halyard off to the bow, undo the forestay from the lower fitting, and the lower fart of the furler comes apart relatively easy. Swap out the drum, reassemble and hoist the sail and have a good time!
MUCH quicker than fighting with corroded bearings.