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Yanmar Anode carrier bolt

toph3r

toph3r

New Member
Ran into some engine drama earlier this year when I found the anode carrior bolt in my Yanmar was seized. With much trouble, I was eventually able to get it out. For a few reasons I decided I wanted to try and replace that bolt. (No. 50 in the below diagram)
Yanmar CFW.jpg


I have been unsuccessful in finding the part available anywhere, but a few yanmar distributor sites listed that the part number 124220-09320 had been replaced with 122780-09320, so I ordered. Of course it did not fit properly :) either the threads are different or the threads in my assembly are so jacked up that the new bolt wont work (or maybe "D. All of the Above").
Bolts.JPG

The old bolt does screw in relatively well, but it is fairly well used (even the square bolt head is warped). I've tried, without success, to use a bolt extractor to try and get the stub of the zinc out, so now I am just out fishing for ideas, hoping one of you guys might have something clever. Some thoughts I had were:


  • Drill (not bolt extract) the Zinc stub and try to re-tap it. Since it would seem that tightness doesn't really matter (it just holds the anode in place), that might work?
  • Try determine the bolt size and pitch and see if I can source a generic bolt, then tap it with the Zinc thread.
  • Drill and tap the old bolt with a larger thread and find a different set of zincs to use in the motor.
  • Find a larger bolt and drill and re-tap the assembly with a whole new bolt.

Any input would be most appreciated.
-Topher

​

 
jimcleary

jimcleary

James M. Cleary
Topher
There is no need to open that bolt to replace the zinc. Remove the 6 small bolts to remove the heat exchanger end plate, use a Channellock pliers to unscrew the zinc from the inside. The rusted in bolt never has to move. While the end plates are off, a 3/16" wooden dowel can be used to rod out the tubes. You can even drill a hole in the starboard side bulkhead next to the H/E so that the job can be done without having to remove the unit from the engine. I clean out Dana's H/E and renew the zinc every other year.

Jim
 
toph3r

toph3r

New Member
Ultimately that is how I got the bolt out, by removing the assembly cover. However unfortunately the "head" of the zinc snapped off from the threads, and thus far I have been unsuccessful in extracting them so I can screw in a new Zinc.
Extraction.JPG

But that is a really good suggestion to just do that for regular maintenance by removing the assembly cover, that had not occurred to me before :)
 
jimcleary

jimcleary

James M. Cleary
Topher
From the photo, it looks like a good machine shop would be able to drill out the broken stud and retap the hole. Remember it is a metric thread on the replacement zinc.

Jim
 
T

terry_thatcher

Terence Thatcher
You might try BoatZincs.com. They have been very helpful to me. Email them your engine type and they may have a solution. When I asked a question by email, the VP emailed me back within a day.
 
toph3r

toph3r

New Member
Just to close the loop for anyone who finds this later. The new anode carrier bolt (122780-09320) was the same thread pitch as the old bolt (124220-09320), the housing was just not in good shape. So I had a machine shop ream out the assembly thread with the same size tap to clean it up. New bolt threads like a charm... now to reinstall and see how bad it leaks. :)
 
M

Mike Nik

New Member
toph3r said:
Just to close the loop for anyone who finds this later. The new anode carrier bolt (122780-09320) was the same thread pitch as the old bolt (124220-09320), the housing was just not in good shape. So I had a machine shop ream out the assembly thread with the same size tap to clean it up. New bolt threads like a charm... now to reinstall and see how bad it leaks. :)
Click to expand...
Did the new bolt also come with the zinc? if not, where did you purchase the new zinc?
 
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