Changing saildrive prop shaft seals

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Slowtack

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I need to change the prop shaft oil seals on the lower end of my volvo 120SB saildrive. Anybody got a set of instructions for this and are there any special tools needed eg puller? Is it difficult to remove the shaft if I have to deal with any shaft wear? All advice welcome.
 
I have a 120SB and I changed my propeller shaft seals and bearing when I bought the boat. Since it was 14 years ago the details are a bit hazy but I will PM you the rather confusing parts of the workshop manual which should help. I didn't have any special tools although the manual says you need them. I pressed the new seals and bearing in using a suitably sized socket but you could get an engineering firm to do it for you to avoid any damage.

Remove the propeller. If I remember correctly, you undo the two bolts holding the rear housing in place and the housing and the shaft just fall out. The shaft can be pulled off the housing then the seals and bearing can be reached. On reassembly the manual advises on the use of shims. I measured mine and the existing shims seemed to be suitable so I refitted them.
 
Did the same thing a few years ago on a 120S. This one (15 years old at the time) did have a run-in shaft. I had the shaft replaced by a Volvo Penta dealer. Basically they took off the gearwheel and bearings and put it on a new shaft. They also replaced the seals in the ring. Not a cheap job as far as I can remember. The shaft is crazy expensive...
The taking apart is not too complicated. after you remove the propeller and the anode you gain access to the bolts that secure the ring that holds the bearing to to the leg. Don't forget to drain the oil first. The ring is simply an exact fit inside the leg itself and also has a rubber O-ring in a groove that you need to replace. You can remove it by rotating it while pulling it from the leg. As said above, at reassembly you need to make sure the ring is not pushed too far into the leg, causing excessive strain on the bearings. Shims are used to achieve a adequate distance. Especially when the shaft has been replaced you will need to readjust the thickness of the shims. The shaft needs to be turnable by hand with a little resistance and with no noticeable play on the bearings. At reassembly time make it just a little tight as it settles a bit afterwards
 
Dipper said:
I have a 120SB and I changed my propeller shaft seals and bearing when I bought the boat. Since it was 14 years ago the details are a bit hazy but I will PM you the rather confusing parts of the workshop manual which should help. I didn't have any special tools although the manual says you need them. I pressed the new seals and bearing in using a suitably sized socket but you could get an engineering firm to do it for you to avoid any damage.

Remove the propeller. If I remember correctly, you undo the two bolts holding the rear housing in place and the housing and the shaft just fall out. The shaft can be pulled off the housing then the seals and bearing can be reached. On reassembly the manual advises on the use of shims. I measured mine and the existing shims seemed to be suitable so I refitted them.
Click to expand...

Just one point of clarification; the seals are fitted back to back and rely on a fine fit on the shaft. When you've got the gear out (mine did need a puller) check the shaft for wear in the way of the seals. There are specialists who can deal with any irregularities and so ensure the oil does not escape when it's all put together.

For info, my seals lasted 10 years before failure (slow leak - which is normal) I don't think there's any point in anticipating failure and I know of no life specification - as with the diaphagm ( 7 years, Volvo spec)

PWG
 
Shaft came out OK. I clamped a visegrip wrench to each side and tapped on them firmly but gently to loosen and remove the outer cover. Sure enough there is some shaft wear. Now in an engineeringshop who say they can rebuild it and restore to the original diameter. A replacement shaft is over £300 plus vat. so the repair is worth a try. Thanks to all for your advice, this forum never fails!
 
PBO or Sailing Today, or perhaps both, did an illustrated guide to this job a year or two ago.

I had hoped to tell you exactly which issue but I can no longer find a back issues index on either of their sites.

Have these indices been removed or am I just a poor looker ?
 
Did my 110S last July, apart from slipping which cost a small mortgage in Menorca it was a simple and cheap job. Everything came apart easily and the seals cost about 3-4€ each + oil. I replaced the anode at the same time and put on a bigger prop. But it only took 2-3 hours with the boat on the hard.

Get yourself a workshop manual form Volvo - I downloaded mine for free from the website. Its worth about 8 hours work!!

Good luck.
 
I did one of mine yesterday and can offer another tip on getting the old seals out , once the bearing housing is removed . I planed up a peice of timber to fit snugly onto the outer seal shoulder , cut it to 50mm in length . then the housing went in the vice with the timber plug outside and gently pushed out both seals . this way will cause no damage to the expensive housing . I also put pu sealant on them as they go in .
 
Since my saidrive is out to have the diaphragm replaced, I thought I'd change the propeller shaft seals. I've done this once before (see above).

This time, I can't remove the housing. It seems to be stuck (corroded?) to the main casing.

Any ideas please?
 
There's an account in the March 2011 PBO (p65-69) which is good. It also mentions fitting SKF "Speedi-sleeves" to cover the wear grooves as an alternative to getting the shaft built up and machined.
 
DaveS said:
There's an account in the March 2011 PBO (p65-69) which is good. It also mentions fitting SKF "Speedi-sleeves" to cover the wear grooves as an alternative to getting the shaft built up and machined.
Click to expand...

Thank you. I hadn't read it (too busy with the boat) even though it was next to the computer. :o

The guide for reassembly will be a useful reminder but the information for propshaft removal was 'and the propshaft extracted'. That's how it was for me the first time. It just pulled off. Now it won't. And I thought I would have it all finished this morning. Grrrr!
 
Dipper said:
Thank you. I hadn't read it (too busy with the boat) even though it was next to the computer. :o

The guide for reassembly will be a useful reminder but the information for propshaft removal was 'and the propshaft extracted'. That's how it was for me the first time. It just pulled off. Now it won't. And I thought I would have it all finished this morning. Grrrr!
Click to expand...

The cover should be glued to the housing so it will put up a bit of a fight. The instructions say use Permatex, obtainable from Volvo, but it's no longer available. Rubber dinghy glue seems to be the current recommendation. There is advice against trying to prise the cover off using a screwdriver or the like. From memory I think I put the propeller nut back on the shaft then used bits of wood to lever between the nut and the leg.
 
PeterGibbs said:
When you've got the gear out (mine did need a puller) check the shaft for wear in the way of the seals.
Click to expand...

My alloy housing now appears to be 'unstuck' but even with my home made puller I can only withdraw it a tiny bit. I can get a 15 thou feeler gauge all the way round but can't budge it any further. I don't want to use too much force at this stage.

What sort of puller did you use? How much force did it need?

This should be a simple job. Aaargh! :mad:
 
Puller ???? maybe the prop but nothing else....

mine took a few taps with a mallet then managed to lever it off...

I pressed my seals out in a vice using an old socket to push them though.
 
That's how I did several years ago but thanks for the confirmation. Now it won't budge. Something's holding it very firmly. I wonder if an O ring has become pinched?
 
I finally got the bearing housing off. What I did was, I loaded it into the back of my car and took it to a marine engineer. :D

Apparently it is not an unusual problem but he wouldn't tell me how he did it.
 
See my second post on page 1. I clamped a visegrip to the narrow profile sections on each side and tapped on them with a plastic hammer to loosen the cover. Slow but no problem.
 
aluijten said:
Did the same thing a few years ago on a 120S. This one (15 years old at the time) did have a run-in shaft. I had the shaft replaced by a Volvo Penta dealer. Basically they took off the gearwheel and bearings and put it on a new shaft. They also replaced the seals in the ring. Not a cheap job as far as I can remember. The shaft is crazy expensive...
The taking apart is not too complicated. after you remove the propeller and the anode you gain access to the bolts that secure the ring that holds the bearing to to the leg. Don't forget to drain the oil first. The ring is simply an exact fit inside the leg itself and also has a rubber O-ring in a groove that you need to replace. You can remove it by rotating it while pulling it from the leg. As said above, at reassembly you need to make sure the ring is not pushed too far into the leg, causing excessive strain on the bearings. Shims are used to achieve a adequate distance. Especially when the shaft has been replaced you will need to readjust the thickness of the shims. The shaft needs to be turnable by hand with a little resistance and with no noticeable play on the bearings. At reassembly time make it just a little tight as it settles a bit afterwards
Click to expand...
Hi, just changed the oil/water seals on my ms25s saildrive. When you say The shaft needs to be turnable by hand with a little resistance and with no noticeable play on the bearings, there is no play on the bearings but not sure if the resistance on the shaft is too much. Can turn it by hand but more than a little resistance. Have reused the existing shims and outer bearing race. Any thoughts welcome. Thanks.
 
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