Squealing ST4000 autopilot

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Chachere's picture
Chachere
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Posts: 825
Squealing ST4000 autopilot

Our autopilot has developed a squealing of late at the wheel, kind of tortured sound. The manual states there is no lubrication or other maintenance to be done (and that any problems call for removal and return of the unit to Raymarine for servicing.) Any thoughts? Does the belt need to be replaced at some point, or could there be other causes?

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

plaineolde's picture
plaineolde
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Posts: 753

couple questions:

1. is it the 'old style' black drive unit?
2. does it squeal while locked in Auto mode, or while it's in standby/unlocked mode and you're turning the wheel manually?

I had the old black drive and it would squeal and chatter while unlocked, especially if I turned the wheel fairly quickly. The problem seemed to be that the clutch was not fully disengaging, leaving just a bit of tension on the belt. I had a number of clutch failures, where it would refuse to stay engaged, so it went in for servicing a number of times before I bought an S1 with the newer, hopefully improved, gray drive.

It would stop squealing after a good heavy rain, so maybe the water was washing some dirt or whatever out of there. I'm in fresh water, so no salt.

Gary and Cathy Price
1997 C36 Mk II Tall Rig/Wing Keel Imagine...
Hull # 1617
Worton Creek, Md.
Northern Chesapeake Bay

Chachere's picture
Chachere
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[QUOTE=plaineolde;9886]couple questions:

1. is it the 'old style' black drive unit?
2. does it squeal while locked in Auto mode, or while it's in standby/unlocked mode and you're turning the wheel manually?

I had the old black drive and it would squeal and chatter while unlocked, especially if I turned the wheel fairly quickly. The problem seemed to be that the clutch was not fully disengaging, leaving just a bit of tension on the belt. I had a number of clutch failures, where it would refuse to stay engaged, so it went in for servicing a number of times before I bought an S1 with the newer, hopefully improved, gray drive.

It would stop squealing after a good heavy rain, so maybe the water was washing some dirt or whatever out of there. I'm in fresh water, so no salt.[/QUOTE]

Given the age of our boat, I assume I have the "old style" unit -- the round thingy on the wheel is black, if that's what you mean. I'm familiar with the chatter sometimes when its disengaged, but that's not the issue. The squealing is when its in autopilot mode (and its a new characteristic, that's just cropped up in the past week or so).
If rain can cure it, as you suggest, then I should be in great shape after Irene. (Haven't used it since then, so I won't know until this weekend.

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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Ken Juul
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Posts: 72

Standard maintenance for the wheel drive units is a thorough fresh water washing. Manual states after each use, think weekly or monthly is more appropriate.

Ken and Vicki Juul
SV Luna Loca
C34 #1090
Chesapeake Bay

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stu jackson c34
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Posts: 1270

You might be interested in Reply #3, here: [url]http://www.ybw.com/forums/showthread.php?t=247520[/url]

Provides a link to repair manual pdf.

Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)

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Chachere
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Posts: 825

Thanks to all for your helpful responses -- especially the link to the manual. I'll let you all know how it turns out!

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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Chachere
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Joined: 10/27/10
Posts: 825

[QUOTE=Chachere;9924]Thanks to all for your helpful responses -- especially the link to the manual. I'll let you all know how it turns out![/QUOTE]

Answering my query:
A good rinsing (first by hurricane Irene, and then with a hose) seems to have now cured the problem.
Thanks again, all!

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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