Help Removing Output Coupling from Transmission

[Beersmith]

I have an oil leak around the output coupling on my transmission and need to replace the seal. The transmission is a Kanzaki KM4A attached to a Yanmar 4JH2E.

I looked into the service manual for directions, but they not-so-specifically say: "loosen the end nut with the special tool". The keep saying "special tool" without any reference to what it is.

Manual: Page 7-60

http://sagaforumet.com/yanmar-manual...apittel_7b.pdf

Here is the nut, does anyone know what I need to remove this thing?

[GordMay]

The manual provides part numbers. Contact a Yanmar dealer:
http://us.yanmar.com/where-to-buy/

[capngeo]

^^^^What Gord said,^^^

PLUS once the nut is off, you'll (probably) find the coupler is frozen on the shaft. To "pull" it off, re-couple the prop shaft flange but with longer bolts. Put a spacer of sorts (a large nut works well) and sequentially tighten the bolts. As the flanges come together, the nut will force the output flange and shaft apart. If you find that you have torqued the bolts to the max and nothing moved, double check for a pin or set screw that you missed, then tap the whole assembly with a hammer.

[HappyMdRSailor]

If you want to get mildly industrious, you don't need to buy the tool, you could make one.... Find yourself a piece of flat bar stock, measure the shortest distance across your special nut... i.e. inside notches, and hole saw the stock to that size... pattern the outside circle diameter, and dremel out the tangs....

Capngeo has a great idea, but a universal puller would do the job just fine... Every (cruiser) boat should have one...

Start spraying the penetrating oil now... Before you do anything else...

[rigormortis]

I had exactly the same problem last year. I had the 'special' tool fabricated--just take the measurements with a good vernier caliper-- sprayed the hell out of the area (for days) and no luck. Remember, you must cut the notched retaining ring first of all--you can see where it indents the square cut out on the retaining nut. Or, at least, pry the notched dimple clear so the retaining nut can turn. It is a special locking ring, punched in to prevent backing off of the retaining nut. Mine did not split and I was able to use it again.
I ended up removing the Kanzaki transmission entirely and took it into the workshop (Subic Bay, Philippines). We had two guys locking the transmission to the table and two guys on a large pipe extender to provide leverage on the 'special machined tool' . I'm talking about a 6 foot pipe. I kept my head below the table, knowing something would take my eye out.
There was a lot of profanity and then 'bang', the nut loosened. Replace the input seal as well as the output seal while you have it on the bench. Cheap and peace of mind.
We discussed heating the nut but too much negativity about damaging metal parts.
I found we just could not get enough leverage with the gearbox in place attached to the engine and I was right.
You might find my pictures and tale on this forum. I posted pics and asked a lot of questions but it was an old mechanic in Subic, CV, who got it done.
Maybe go to the Philippines. They fix things there. Can't afford to buy new stuff. Not like Canada or USA.
Good luck, and if you have any questions....
powellpjc@gmail.com
Pete.

[perchance]

The rude and crude method is to use a brass drift on the notches to loosen the nut. Some heat may be required and odds are you will mushroom the edges but in a pinch it works.

[boden36]

Before you make or buy the special tool there is a procedure I have used that sometimes works.
Get a ring or socket spanner that will slip over the special nut. Find some round bar or old bearing rollers that will just jam between the cutouts in the special nut and the spanner. This will lock the two together and you should be able to undo the special nut.
It would also be worthwhile to drill a length of flat bar or angle to fit two of the holes in the flange in order to hold that bit steady.

Regards,
Richard.

[Beersmith]

Thanks a bunch for all of the ideas. I will follow up once I figure it all out.

[RabidRabbit]

Buy a quality impact socket (for air wrench) that has a thick wall and is the diameter of the nut. then take a grinder and nip out everything thats not the three legs to fit the holes. Within reason your better off buying the tool, even if cost $80.

[Beersmith]

small update:

I called my parts guy and he says the socket costs $150!!!!

will either make one or take it to a shop. the engine is in my garage and the transmission easily removed.

[HappyMdRSailor]

Beersmith...

Honestly.... I myself would knock that off with a drift and a hammer... Do your seal business, and drift it back on... You have 4 tangs to pound... If you feel like you buggered it up enough, you can probably buy a new nut for less than $10...

[delmarrey]

What it takes is a spindle nut wrench. Yours has special sized lugs so you would have to get it from yanmar. Or have it special make.

But the brass punch is a secondary as long as the hammering isn't transferred to the gears.

[Maxs]

I had the Kanzaki tuff torque on my transmission.. It is a very weird coupling with clutches on the inside.. Yanmar used the on some models around ten years ago.. I wanted to get rid of it and install a regular coupling.. So, I removed the starter, put a big screwdriver between the flywheel teeth, and we were able to unthread the lock nut. Remember that is left hand threaded... It came out really easy.. It was still very well lubricated. I put some grease on the new coupling and installed it with a new regular nut... I was going to replace the seal, but the dealer sent me a o-ring instead of the seal....... I did noticed that is no special seal, so it can be bought everywhere...

[Celestialsailor]

Originally Posted by perchance

The rude and crude method is to use a brass drift on the notches to loosen the nut. Some heat may be required and odds are you will mushroom the edges but in a pinch it works.

...and if it doesn't work, you would be unable to get the proper tool to fit on it with all the buggered edges. It seems a few bucks for the right tool is the way to go with an impact driver.

[GrowleyMonster]

Buy, rent, borrow, or make a proper tool. You are not in a hurry, right? I would start by grinding one out of an impact socket. Your Dremel is your friend. Do not let the socket get too hot to hold. Grind a bit then dunk it in water. Softly softly catchee monkey. You could take a piece of steel plate and cut it to fit, then weld it to a 1" pipe big enough to fit over the other bits and bobs, then weld a socket to that so you can turn it with a 3/4" drive ratchet or breaker bar.