Volvo 120S Saildrive Anode Bolt Stripped

[patprice]

Need some advise please concerning my 120S Volvo saildrive.
Refer to the picture below.
The anode (23) is connected to the bearing housing (3).
The threads in the housing are stripped. Repair needed.
I am in Australia, B42 in Greece but I am fairly certain the housing is stainless steel?
My intention is to fix the stripped threads using stainless helicoils. Which I hope should be a reasonably simple task.
Comments please. Is using helicoils the right approach etc.
A new housing is rather expensive and I hope a repair will be satisfactory.

[belizesailor]

Originally Posted by patprice

Need some advise please concerning my 120S Volvo saildrive.
Refer to the picture below.
The anode (3) is connected to the bearing housing (3).
The threads in the housing are stripped. Repair needed.
I am in Australia, B42 in Greece but I am fairly certain the housing is stainless steel?
My intention is to fix the stripped threads using stainless helicoils. Which I hope should be a reasonably simple task.
Comments please. Is using helicoils the right approach etc.
A new housing is rather expensive and I hope a repair will be satisfactory.

You mean anode (23) connected to housing (3) right?

Im not certain of the material of the seal housing. Given that the drive leg is aluminum, stainless would not be a good choice. Ive never noticed any bi-metal corrossion in that area either so Im guessing they are more compatible metals. Maybe its an aluminum alloy?

[patprice]

Yes anode is 23 sorry for that confusion.
If the housing is an alloy, can I still use helicoils?

[patprice]

It may be relevant that the bolts holding the anode onto the bearing housing are stainless. This would seem to support stainless helicoils would be suitable?

[Kerry1]

The housing to which the anode is machine screwed is an aluminium alloy of some description. The Screws are Stainless. Can't advise on stainless helicoils. A simpler option may be to drill out and re-tap larger screw size. The anode I imagine will easily accommodate the larger size and it's a soft material as well. Would have to be really careful of sizing new thread in the housing making sure there is plenty of wall thickness left.

[JasonS]

I agree with the idea of retapping. It's a metric bolt. Look and see what the next size SAE bolt is and consider tapping to that size. It's likely around 1/100th of an inch or even less difference. Yes, you'll then need to get some SAE bolts for that one hole - be sure to mark it so when you're changing anodes underwater you don't mess up the threads on that hole or other holes in the future.

[patprice]

Thanks Kerry and Jason. I will get back to Greece in May with gear for both.....tapping and coils.Taps and helicoils are quite cheap.

[Kerry1]

I am going to write a new post on an incident that may be of interest for those with Bavaria's, particularly if they are set up with a Lewmar (which was once actually Whitlock) pedestal steering and engine control.

[patprice]

Very good. Any idea why my wheel lock does not lock?

[Kerry1]

Sorry I'm not sure how that piece of kit works exactly. At a guess the shaft has a rod thru the middle actuating a friction plate on opposite end. Screw brake knob in and the rod tensions one plate against afixed disc. Perhaps some lubricant has inadvertently found its way between them? Have a look through inspection plate on stbd. Side. Or 4 a better look remove screws holdin fascia plate for plotter. Should give direct access to opp end of shaft holding steering chain sprocket. I don't know what model u have but it's appropriate for a B38.

[Kerry1]

Another thought regarding new thread in housing. That piece should be removed on a regular basis and new back to back seals replaced to keep drive oil in and seawater out. An ideal time perhaps to take it to machine shop for retappinng both screw threads. I always get them to press out old seals out and replace.

[blueazimuth]

Take the housing to a machine shop. This is not a home fix job.
Liberally coat the new bolt(s) with an anti seize compound which does NOT contain copper. Read the label. Alternatively, Tuf-Gel is excellent for this job.

[olaf hart]

Agree with blue, a couple of years ago I took the collar and shaft to the local VP dealer, who changed the seals in an afternoon for a surprisingly low cost (for VP), it is mostly labor and you minimise the cost by dropping it in.
He mentioned those anode bolts are a problem and always uses some form of loctite when he installs the zinc.

[epatant]

Just a caution if h use a saildrive- never use hull anti fouling on your leg-it causes all sorts of odd corrosion problems: use special leg/prop anti fouling- many brands available, mostly in spray cans- and mask anodes b4 spraying. I have a perfectly functioning 120s that was 40 years old last year!

[patprice]

Thanks for the above replies.
My thoughts have changed about doing the job myself. Reckon now I will take the piece to a machine shop and get the job done there with seals.

The boat is at Aktio Marina, Prevesa. I know of machine shops in Nydri and Lefkas. Does anyone know of one in Prevesa?

Thanks all.