Rusted propshaft coupling

[cborden3152]

I'm in the process of removing this old Volvo Penta MD5A and I've come to the point where I need to disconnect the propshaft. It's rusted to the point that I had to get a dremel to figure out where the screws were. I'm thinking I'm most likely have to use a grinder to cut it off. Anyone have a better idea?

[deblen]

This may help. / Len https://www.marinepartseurope.com/en...=41&View=15047


https://www.volvopentashop.com/epc/e...%2F7742220_059

[DougR]

The page linked by Deblen takes you to the wrong gearbox. Your engine has an MS or MSB gearbox, and the propshaft coupling bolts thread directly into the output flange of the gearbox. There are no nuts involved with the coupling bolts.

If you can’t turn the bolts, cut the heads of the bolts off with your Dremel. Then you can slide the engine forward and release it from the propshaft.

[cborden3152]

Originally Posted by DougR

The page linked by Deblen takes you to the wrong gearbox. Your engine has an MS or MSB gearbox, and the propshaft coupling bolts thread directly into the output flange of the gearbox. There are no nuts involved with the coupling bolts.

If you can’t turn the bolts, cut the heads of the bolts off with your Dremel. Then you can slide the engine forward and release it from the propshaft.

I thought that looked a little funny. I think I will do that. Next day off is next week but I will update afterwards. I took almost everything off the engine I could beforehand, wonder how much it weighs?

[DougR]

244 lbs., including the gearbox

[cborden3152]

I got my engine free finally today. Tried to separate the propshaft coupling plate from the transmission by cutting into it with a diamond bit blade on my dremel. Started tapping the crease with a chisel and eventually broke the bearing inside the transmission. The back piece came loose and is now attached to the prop shaft. But at least I can get ready to pull the engine out now.

[Bill Seal]

Congrats, a used MSB tranny (unbroken) is probably worth a grand on EBAY, if it'x broken, it's scrap..

[C420sailor]

Ouch

[cborden3152]

Ok, so I got my old engine out but now I need to remove the last bits from the prop shaft. I can pull on the transmission coupling and the propshaft will pull out too! Is it made to do this? Will water come gushing in if I pull it all the way out or is it made to do this? Has anyone dealt with this before?

[S/V Adeline]

Assuming there is a shaft zinc and propeller attached on the other end, the shaft should stop at the zinc.

[cborden3152]

Does that mean it won't come all the way out?

[cborden3152]

Or, if the coupling was removed would it slide out the other way?

[cborden3152]

At any rate I need to remove the coupling and I am running out of ideas. I have cut on that sucker for hours and it is still stuck on there.

[stormalong]

Looks like you have a traditional stuffing box. Without removing the prop there is no way for the shaft to pull through into the boat. The shaft won't push it's way out of the boat when it is stationary. If you sail or tow the boat it is possible to loose the shaft. The packing might leak a bit if you pull the shaft into the boat and the shaft is dirty with marine growth.

A Dremel tool is not up to the job of cutting off the coupling - an angle grinder with a cutoff disk is the tool to use. Cut until you are close to the shaft but don't cut into the shaft. Do the same on the other side. Drive a wedge into the cut to crack the remaining part of the shaft.

I had to do this once on my present boat. After that I started spraying the coupling with Boeshield T9 periodically and the coupling looks like new.

[cborden3152]

Originally Posted by stormalong

Looks like you have a traditional stuffing box. Without removing the prop there is no way for the shaft to pull through into the boat. The shaft won't push it's way out of the boat when it is stationary. If you sail or tow the boat it is possible to loose the shaft. The packing might leak a bit if you pull the shaft into the boat and the shaft is dirty with marine growth.

A Dremel tool is not up to the job of cutting off the coupling - an angle grinder with a cutoff disk is the tool to use. Cut until you are close to the shaft but don't cut into the shaft. Do the same on the other side. Drive a wedge into the cut to crack the remaining part of the shaft.

I had to do this once on my present boat. After that I started spraying the coupling with Boeshield T9 periodically and the coupling looks like new.

What's to stop the shaft from sliding back out of the boat once I remove that coupling?