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The only other vacuum issue I had with the vacuum unit (excluding the toilet) since this maintenance was done was with the vacuum switch. The symptom is the unit will run non stop or it will run and quickly loose its vacuum and restart again because the vacuum switch membrane is cracked and the air come through it. The easy way to find out is to remove the switch, clean the membrane on the switch and inspect it carefully.

@@svkiara1040 thank you, we've found that the inlet side was at fault, the generator itself was pulling a vacuum. Jubilee clips now tightened and all working :-)

No special tools needed just to change the seals.

6:06 😊

As you can see at 6:15 in the video, my bellow is also not tight in the cylinder. This is not critical since the way this bellow works when it is pulled up is by changing the volume in the cylinder chamber by the volume it is compressed which create the suction in the inlet pipe as long as there is no leak from any other joint. What maintain the vacuum in this chamber (cylinder) are the 2 o'ring seals you see at 5:39 and 5:41 and also the duck bills from the outgoing pipe and the o'ring seal between the cylinder and the tank as shown at 2:40. As long as the bellow clamps (half rings black at 6:04) are tight to hold it in place this should be ok.

The only way to have water building up in the bellows chamber from the design I have is a leak from the inner o'ring (at 6:54 in the video) or the bellow itself, not sure about yours. Maybe the o'ring sealing surface on the cover is damage? or the o'ring itself was damaged on the installation (sometime this happen). Since you used a rebuilt kit I would assume the bellow was good but you never know, is there a small crack on it?

The brass tool is just a metal bar I had in my stock of various metal parts at home, it has nothing to do with boat or engine tooling, but it is just the right size for this job!

If you look from 3:25 to 3:37, you can see the bearing and shaft removed from the bearing housing in which the seals are installed. The seals are installed after the bearing on the shaft (propeller end) so there is no need to remove the bearing to replace the seal, you just remove the shaft with the bearings assembly as shown at 3:32. The seals will remain in the housing and you can replace them.

@@svkiara1040 thanks!. I guess the SD20 is a bit different from Volvo 120s, in which the bearing outer racing is not together with the bearing rollers, and when you pull the shaft assembly, the outer racing remains connected to the housing, and has to be pulled out separately to clear way for pressing out the seals (if you don't remove the bearing racing, have to pull the seals with a needle-nose pliers, which is messy and dangerous)

@@yangyang3175 Correct, the Volvo 120s has a taper roller bearing where the outer race is removable and press in the bearing housing. On the SD20, the bearing is a standard roller bearing where the outer race is not removable and the complete bearing slide in the bearing housing with the shaft assembly.

Hello, thanks for bringing up this important point. The service manual recommand to check the backlash (the gap between the gears) when you replace some of the parts like bearings, shafts, gears or housing and to adjust this gap if out of tolerance by using shims sets available for this purpose. The only way to check the backlash on the gears is when all parts are assembled in position. However, the measurement of backlash for the lower gears unit is not possible directly on the gears since there is no access to the gears when it is all assembled. So you need a special tool not even shown in the service manual to be able to measure it. In my case as shown on this video, the only part I changed which have an impact on the backlash is the large roller bearing which has a very tight manufacturing tolerance. Based on this fact, I assumed the backlash would remain very close to the previous assembly. Once all parts were reassembled, I could feel the backlash on the shaft turning it back and forth, then I assumed the backlash had not reduced to a point it would damage the gears. Also, based on some research I did, a slightly larger backlash for bevel gears should not have too much impact for the this type of application (saildrive). Not having any better technical options to check the backlash and having more concern about the bearings conditions, I took the decision to go as shown in this video. However if I would change many parts at the same time (bearings, shafts, gears, housings) I would definitely take more time and built a tool to measure the actual backlash in the gears and do the adjustement if required. This would be a much more involving project requiring a possible complete disassembly of the lower gear unit.

Hello, I'm glad this help you! You are lucky, I'm on my boat and have the pulling plate with me so I just measured both dimensions: The bolt circle for the pull-out holes is 124mm (holes dia are 12mm) and for the bolting holes it is 85mm (holes dia are 7mm).

Usually you can just tap on the bearing housing where it sticks out for the bolts and it will start turning then a screwdriver will easily pop it out the rest of the way. We have done it this way many times.

Hello Val If you want to move the outer seal only (water seal), this will work and move this seal by approx 3mm. However see my comments in my reply to Kevin Santella about the possible corrosion issue on the shims.

Hello David, you can purchase one, part number is 196420-92040 and you will find some vendors on the web if you search this part number. However, as you will find, this is really expansive and make no sense for what it is: a metal plate with few holes. It could be of any shape (rectangular, round or square) and made from aluminum or steel or anything stiff enough and you could probably get it fabricated at some small manufacturing facility if you provide dimensions. You can find nominal dimensions in the service manual for this part (O.D = 148mm, ID = 70mm, pull-out holes = 9.5mm, bolting holes = 6.5mm) It does not provide bolt circle dimensions for the pull-out holes and bolting holes so you would have to measure it on your saildrive (I could provide these dimensions from my puller, but it is on my boat which I have no access for now)

Thank you for the comment. You are correct, the shim is the part described as "spacer" in the manual. It is not possible for the original shim to create wear because its inside diameter is much larger than the shaft diameter and can not create wear. Unless you do not have an original shim but instead a custom made one with a much smaller inside diameter very close to the shaft diameter?

@@svkiara1040 Ahh ok, that's interesting. I had convinced myself the wear was from the shim because the width was identical. Its a very small wear anyway so im not concerned yet. I have however made a mistake with the installation. I couldn't get the genuine yanmar oil seals so I bought SKF oil seals of the exact same size. I have since learnt that the sprint inside the seals may not be stainless (the shop doesn't know and the data sheet is unclear). Do you happen to know If the Yanmar seals have stainless springs?

@@peterharrison8924 The oil seals Yanmar use for the SD20 are NOK AC2081E0 which are SC type (looking in the NOK catalogue). Specifications in their application guide (which you can find online) for the SC type are: The spring is made either of piano wire (steel) or hard-drawn copper wire. Both materials are not recommended for sea water...So your SKF seals should be as good as the originals NOK from Yanmar! I have not checked the spring when I removed the old one if they were corroded, but I will take a closer look the next time. I also put waterproof grease in the groove (as you can find on the video) which might help to protect the spring.

@@peterharrison8924 replace the spring with an o ring that's the same size as the spring and it will last much longer than the spring.

There is no sound. I choose to put only written details at important steps in the video

Thanks!

Good to hear Erik! I’ll set the seal that way! That should do it best in my case.

Excellent, I am hopeful this method works. Next year when I haul out I will remember to re-post the results here. :D

The inner shim isn't needed if you are careful about how far you drive the seal in. If the shafts has a groove try to position the seal outside or inside of the groove so it rides on a smooth part of the shaft.

I'm happy to help. You can use two shims and there are two configurations possible: 1- If you want to move only the inner seal (oil side), you can use 2 shims between both seals instead of one. 2- If you want to move both seals, keep only one shim between the 2 seals as per original installation and add the other one as shown on the video on the outside of the outer seal (water seal). This will move both seals by 1.5mm (0.060''). Note: I took measurement and moving the inner seal (oil side) by 1.5mm as proposed in both configurations is the maximum since the seal will become flush mounted inside the aluminum bearing housing and close to the bearing. Also be aware that in the second configuration with the shim installed on the outside of the outer seal (water side), the shim is made of steel, which means it might corrode over time because exposed to saltwater (unless you can find a stainless steel shim). So in this case it is a temporary fix until you can have the shaft either repaired or replaced. I had one shaft sent to a specialized company which rebuilt the worn section with hard chrome and grind it back to tolerance (this was almost 10 time cheaper that to replace it).

@@svkiara1040 Thanks for the reply. My issue is on the water side like yours but I was just wondering about if it was on the oil side. When you mention a temporary fix, since water will be against the shim how long will this last (estimate) in salt water? My Yanmar dealer suggested a speedi sleeve in lieu of moving the spacer. Any experience with these? The groove issue seems to be a prevailing issue due to the seals. Ive seen it on many forum posts.

@@kevinsantella2447 I have no idea how long this steel shim will last in salt water but I put a lot of waterproof grease to protect it. I will find out next time I replace the seals how this was affected. I look into the technical datasheet from SKF about their Speedi Sleeve and this seems an interesting option I might try next time. The important point looking at the sleeve selection instructions are about the careful measurement of the actual shaft diameter. As per example, the shaft I had repaired (hard chrome coating) was originally between 34.83mm and 34.85mm in diameter, which means this would have required Speedi Sleeve SKF part no 99138. However, when looking at the NOK seal no. AC2081E0 provided by Yanmar on the SD20, the required shaft diameter and tolerance for this seal should have been 35mm -0 +0.06mm (from NOK technical datasheet). Which means the original shaft I had was already out of tolerance. This had probably not helped my leakage problem when combined with the scoring? Adding the thickness of the Speedi Sleeve (0.28mm) to my shaft would also had put it out of tolerance for this seal. This would have bring my shaft to a diameter of 35.41mm way over the max 35.06 mm, not sure what wear effect it could create since there would be more seal lip force applied to the shaft surface. Also, the Speedi Sleeve width will cover the shaft for only one seal, which I understand is ok in your case. To cover both seals you would need 2 Speedi Sleeve side by side, as shown in their installation guide. The last point is that the installation tool provided with the Speedy Sleeve will not work since not deep enough to get pass the shaft spline section, so you would need to make or get a special installation tool. As in many technical issue, there is no black white answer. I have been told the hard chrome coating is supposed to outlast the shaft... I'm also interested to test the Speedi Sleeve which SKF advertise as better than chrome coating.... Since I have 2 saildrives, I will have the opportunity to test both options, but the results will come only in few years...

@@svkiara1040 Thanks for the response. I too have 2 sd20's on my cat. Im game to try either the speedi sleeve or the spacer placement while my boat is out of the water now. I pull it every two years to do bottom and seals. May do a short haul or beach it to just check (by draining some oil in from the plug on the bottom of the drive) to see if it is keeping the water out. Thanks again. Glad I could offer something to the options as well.

@@kevinsantella2447 You are welcome! and I also thank about this Speedi Seal option, which I wasn't aware of.