Separate SD20 Saildrive from the Yanmar Diesel

[Sailorman Ed]

Have to replace the large water seals for the SD20 saildrive (old and one side leaking). SB side came apart and just pulled the SD20 out and brought it home. The port side was more of a challenge. Pulled the motor mount bolts and with effort got the unit pried apart 1/4", sprayed some PB Blaster inside but that was it. Finally pulled the engine (2 cyl) and the SD20 as one unit. Not easy but we did it. Put it into the trailer and brought it back home (7 hours). I know there is a dampener bolted to the flywheel (like a clutch disk) but how do I get it apart?
Once apart, what is the best way to separate the lower saildrive from the upper section (6 or 8 allen screws - 20 years together)

Will take a pressure washer up and degrease and clean and paint the engine bays before reassembly.
Ed

[Ex-Calif]

The 3 jpgs at this link should help with the seal replacement.

As far as separating the motor that's a quandary. Should just slide apart.

PDQ Owners Forum • View topic - SD20 saildrive diaphragms replacement

[colemj]

AFAIK, after the bolts are out, there is nothing holding the drive - it is just a splined shaft slid into the damper plate splines on the flywheel. If you move it in and out that 1/4" a few times, maybe it will loosen?

You have one off, so you should be able to see exactly what goes on in there and how it is put together.

Mark

[Sailorman Ed]

Mark - yes, looks like a VW transmission into a clutch disc with the splines rusted to the disc because the PO did not put any grease on the shaft. Will move it into my shop tonight and try again. If not, will preload it, spray in more PB Blaster and let it sit another day.

Ex-Calif - thanks for the link. The Volvo set-up looks similar. I noticed that Volvo sells a nice kit with instruction sheet. The supplier I got my parts from (Oxford Boatyard in MD) was kind enough to email me some pages to help with installation and once I had the parts, does not look too difficult not that the units are out.

Do I want to add "linecutters" to cut fishing line while I have this apart?

thanks again to all...Ed

[Ex-Calif]

Originally Posted by Sailorman Ed

Mark - yes, looks like a VW transmission into a clutch disc with the splines rusted to the disc because the PO did not put any grease on the shaft. Will move it into my shop tonight and try again. If not, will preload it, spray in more PB Blaster and let it sit another day.

Ex-Calif - thanks for the link. The Volvo set-up looks similar. I noticed that Volvo sells a nice kit with instruction sheet. The supplier I got my parts from (Oxford Boatyard in MD) was kind enough to email me some pages to help with installation and once I had the parts, does not look too difficult not that the units are out.

Do I want to add "linecutters" to cut fishing line while I have this apart?

thanks again to all...Ed

I think the key steps are making sure you don't lose any of the shim stack when the leg comes off, cleaning the surfaces where the two seals go, using gasket seal only on the paper gasket, using the right tightening sequence and torque and safety wiring of 4 bolts.

Use a good quality allen key or an allen driver in a ratchet/breaker bar.

Line cutters are a personal option. Singapore waters are pretty fouled and I have snagged stray line only twice in 5 years. There are enough legitimate fisherman with pots and lines (bouyied) that I would not want to accidentally cut some working guys line - that just me...

Another decision is whether you replace the shaft seal while you have the leg out.

[colemj]

Originally Posted by Ex-Calif

Another decision is whether you replace the shaft seal while you have the leg out.

That isn't a decision - they are $10 seals that take 10 minutes to replace, and failure of them means damage (and another haulout)! Many people change them as regular maintenance during every haulout.

Mark

[Sailorman Ed]

Mark, I ordered a shaft seal (and O-rings) when I ordered the saildrive gaiters. I told Yanmar not to even tell me the cost of the parts because I did not want to get upset!! I will take the shaft seal down to my local bearing house and get a couple more, I am sure the cost will be 10% of what yanmar charges.
Cleaned out the current project in the shop tonight and the engine/saildrive unit will go in tomorrow night. PB Blaster onto the cover holding the shaft seal - expect it to be difficult to get apart.
Ed

[Sailorman Ed]

After sitting for a week with some PB Blaster, I added a couple more wedges and then one wack with the small sledge and ti popped apart. Seems when the seals failed, enough seawater got into the engine bay to enter the flywheel housing and then got flung around. The flywheel has light surface rust but the dampener is quite rusty and the saildrive splines were rusted quite well to the dampener. Will clean it all up well and apply a liberal coating of grease for assembly.

I looked at the banacles grwoing on the capscrews holding the lower saildrive unit and anticipated a real problem getting it apart. I was jsut amazed how easily the came apart, including the 4 small ones holding the anode and then the 2 under it holding the bottom hub. Will replace the lower shaft seal and the the large watertight seals and then back into the boat after I return from China.

[Sailorman Ed]

Got the dampener off tonight. It is slightly warped and has more rust than normal where it was sitting in salt water for a while. Knowing that Yanmar thinks all their parts are made from gold, how important is it to replace this will a new dampener?

[Ex-Calif]

I'd check the price for "fun" but this is a mechanical device.

If the springs in their housings are tight and not loose or worn I would clean it up and reinstall it.

if it were a clutch plate I might consider it more.

[Sonosailor]

I have an SD20 removed, and notice that the spline shaft is not lubricated or greased, and neither the service manual nor the installation manual says anything about it. Should I grease the spline shaft before reassembly?

[Sailorman Ed]

Sonosailor,
I would DEFINITELY apply a light coating of grease to the splines.
This is not like a clutch where you need to worry about grease getting on the clutch disc. And I made sure all the bolts were clean and got a very light coating of grease so they would come apart again in the future.

I did have to take this apart again to replace the main oil seal behind the flywheel. All came apart very easily then.
Ed

[Sonosailor]

Thanks Ed. In a boatyard in Grenada, and behind schedule. I'll post some opinions on diaphragm replacement when I get caught up and fly home to good internet (and showers).