Saildrive Diaphragm Replacement Schedule

[out42]

Originally Posted by colemj

Was there a noticeable crack or hole in the exterior diaphragm?

The Yanmar dual diaphragms are notorious for false water intrusion that sets off their alarms. Condensation can cause water accumulation, as well as water leaking from the raw water valve through the drive. Also, if you regularly have water around in the engine compartment, the seal between the two seals is not very water-tight and it can leak between them. All of which looks like an exterior seal failure (especially when that warning alarm goes off).

Mark

A tiny crack. The sensor was removed and left out for a while, the chamber dried but the ingress continued, so had to be done.

[colemj]

Originally Posted by 2Hulls

For sure easier, but a lot less than $500 to DIY.

…...
For any Volvo owners - do NOT buy the "all inclusive" kit from Volvo that includes the rubber seal and a few other things. This kit is intended for all Volvo drives and includes some stuff I didn't need plus, as a bonus, it included the wrong gasket for between the adapter plate and tranny. I had to get two of those separately.

Great, now you tell me. I already bought two of the kits for $473 (hence my $500 reference), and I have the same drives as you, so I guess I will be looking to get the gasket. Do you have a part # for that?

Edit: What kit part # did you get? I just checked mine and the gasket included is the one for my saildrive model. It seems like everything included will be used in the change. The kit part # I bought was 21389074 (ex 894534), containing gasket #3856834.

Mark

[colemj]

Originally Posted by out42

A tiny crack. The sensor was removed and left out for a while, the chamber dried but the ingress continued, so had to be done.

Thanks for relaying that. You are the first one I have heard with an actual failure. It is good to see that your failure mode was as I have been expecting - not catastrophic, but only a leak that can be handled until repair.

Mark

[Djarraluda]

The biggest risk factor is probably marine growth. Especially if there is a leak between the two seals, get a crusty old barnacle growing there and then, any movement could cut the seals.
This is a known problem with sterndrives or the retractable drives and I know a boat that sat idle for years, then when sold, someone presumably twiddled the steering - result was severe water leakage and down she went.

[colemj]

On the Yanmar double seal system, it would be impossible for a barnacle to get between them. They only way that could happen is complete failure of the exterior seal - which would make a barnacle superfluous.

With many thousands of saildrives in operation for many years, I have never heard of marine growth being a concern with regard to the seal.

Mark

[2Hulls]

Originally Posted by colemj

Edit: What kit part # did you get? I just checked mine and the gasket included is the one for my saildrive model. It seems like everything included will be used in the change. The kit part # I bought was 21389074 (ex 894534), containing gasket #3856834.

Mark - I think you're OK.

My kit was the same number 21389074, but it included gasket 3586693. This looks like the gasket for a 130/150 drive. The correct gasket is 3856834. Attached is a picture of the two different gaskets - the correct one on the right.

I recommend you also obtain the seal for the transmission input shaft, number 873094. Now's the time to change it, when you have the drive out of the boat.

Another thing good to know is that SKF Speedi Sleeve 99125 is the size to get for the prop shaft. I used two on each shaft due to scoring from the seals. The seals are 873108.

Feel free to bug me with questions as you go. I like really old rum....

Dave

[colemj]

Originally Posted by 2Hulls

Mark - I think you're OK.

My kit was the same number 21389074, but it included gasket 3586693. This looks like the gasket for a 130/150 drive. The correct gasket is 3856834. Attached is a picture of the two different gaskets - the correct one on the right.

I recommend you also obtain the seal for the transmission input shaft, number 873094. Now's the time to change it, when you have the drive out of the boat.

Another thing good to know is that SKF Speedi Sleeve 99125 is the size to get for the prop shaft. I used two on each shaft due to scoring from the seals. The seals are 873108.

Feel free to bug me with questions as you go. I like really old rum....

Dave

Yep, the ones in my kit are those on the right.

I just changed the shaft seals and don't have any scoring, but am considering having a couple of speedi sleeves on hand just in case.

I considered changing the rear seal, but it seemed to involve pulling the flywheel and being somewhat involved, so I decided not to order it. Is that what you were referring to regarding the input shaft seal? Or is that a seal in the saildrive shaft?

Mark

[Kerry1]

Originally Posted by Sonosailor

Seems to be no thread specifically on this. How often do saildrive diaphragms fail, how often should they be inspected and how, and what is a reasonable replacement schedule for each manufacturer and each model?

Cat Tales (1996 FP 35) has the original diaphragms in her two Yanmar SD-20s. She also has an interior boot with a water sensor to give us some alternative protection. I really do not hear much about these things failing, and have even asked repair people about them with vague answers (Mechanics at Le Marin, Martinique suggest I show up when one fails, not before). Still, I have a surveyor's report now telling my insurance company that the manufacturer recommends inspection every year and replacement every five years. I know that a decade ago they pushed for replacement every two years; so this seems to be under review from time to time.

Any comments, any experiences? I'd love to hear from Yanmar, but can't seem to find the right contact.

Here is a link that shows a video of a Volvo Penta saildrive diaphragm replacement by what looks like a professional. https://drive.google.com/file/d/0B_y...ew?usp=sharing

And photos of mag reviewing procedure:

https://drive.google.com/file/d/0B_y...ew?usp=sharing

https://drive.google.com/file/d/0B_y...ew?usp=sharing

https://drive.google.com/file/d/0B_y...ew?usp=sharing

[2Hulls]

Originally Posted by colemj

I considered changing the rear seal, but it seemed to involve pulling the flywheel and being somewhat involved, so I decided not to order it. Is that what you were referring to regarding the input shaft seal? Or is that a seal in the saildrive shaft?

I was referring to the seal in the saildrive shaft. It's staring you in the face when you get the drive out. The seal is a bugger to get out, though. The shop manual specifies to pry it out with a screwdriver. I'm surprised it didn't also specify a specific Volvo screwdriver, tool number 19274539.

Dave

[2Hulls]

Originally Posted by Kerry1

Here is a link that shows a video of a Volvo Penta saildrive diaphragm replacement by what looks like a professional. https://drive.google.com/file/d/0B_y...ew?usp=sharing

That's a pretty good video covering the major (and easiest) steps based on what I've recently learned doing it myself for the first time. What it doesn't show, and what has been the toughest part for me, is the re-installation, alignment, and mating of the engine back to the drive. Neither the male transmission spline (on the saildrive) nor female vibration damper spline (engine) are tapered and because you can't see them coming together (at least not on my MD22's and 120S-E's), it's trial and error getting them aligned rotationally, involving hand turning the engine and watching for the transmission to rotate via the oil fill cap on the saildrive all while slowly moving the engine aft via temporary, longer fasteners. My port side came together on the first try - pure blind luck - but I damaged the female spline on the stbd side, thinking they were aligned when they weren't, and had to remove the saildrive again to get at the vibration damper (that includes the female spline) to fix my screw up. During this process a helicoil in the aluminum engine mating plate was damaged and I had to replace that. This all took a bit longer than the 5 minutes or so of the video....

Dave

[Kerry1]

The vid definitely is just showing the highlights. Lining up splines you can't see is always tricky. Pulled my tractor apart without trolley jacks or a crane and replaced the clutch once. Putting it back went really well until I went to use the clutch. I had put the plate in back to front and had no travel. Out it had to come again. Thankfully a mechanic frnd came along with a trolley jack and we had it done in a couple of hours. Lots of things to disconnect.

[colemj]

Originally Posted by 2Hulls

I was referring to the seal in the saildrive shaft. It's staring you in the face when you get the drive out. The seal is a bugger to get out, though. The shop manual specifies to pry it out with a screwdriver. I'm surprised it didn't also specify a specific Volvo screwdriver, tool number 19274539.



Dave

Thanks. Just ordered it. There also seemed to be a random o ring in that area, so got that also just in case ($2).

Mark

[2Hulls]

Originally Posted by colemj

There also seemed to be a random o ring in that area, so got that also just in case ($2).

Could be engine specific - no o-rings there on my MD22's. I'm surprised anything Volvo sells is $2.......

Good luck!

Dave

[Ostinato]

Despite the limitations, the article and video are very useful. Thanks.

Can anyone estimate how long it takes to do one of these the first time? I have replaced damper plates and have that done to a few hours but this obviously much more involved.

[2Hulls]

Originally Posted by Ostinato

Can anyone estimate how long it takes to do one of these the first time? I have replaced damper plates and have that done to a few hours but this obviously much more involved.

If you've replaced dampers, then you're pretty far along already to replacing the saildrive boots since you've already figured out how to support and move the engine(s) forward. Assuming you don't have to mess with bearings and shims in the drive, the drive removal and boot replacement is as pretty straightforward as what's shown in the video and can be done in a few hours non-stop. Extra time if you replace the lower unit seals. Then just add on the time to re-couple the engine which is what you already know from your damper replacement. But with the drive out you have an opportunity to do a proper antifoul on the upper part of the leg that is inaccessible when installed which takes a lot of time depending on what antifoul process you use. For me all of this was all done in the course of a significant refit while on the hard and I didn't do it all at once. And you need extra hands for portions of it.

Dave