Leaking prop seal, seal installed correctly?

After thinking I finally got my new/used boat sorted out, I discovered an oil leak today from the prop seal. After looking at the picture closely, I noticed that the spring side of the outer seal is installed facing outwards. Aren't the springs usually facing inward?

I have receipts showing these seals were replaced 2 years ago, so not sure what's going on. I had the out drive professionally pressure tested a couple of weeks ago and they said it held 15psi for over 10 hours, and held vacuum.

I did lots of searches here and there doesn't seem to be any good step by step how to's for replacing these seals. The manual just describes full rebuild.

Boat is '03 Larson 274, outdrive is DP-SM 1.95

Re: Leaking prop seal, seal installed correctly?

That one is installed correctly. There are actually 2 seals there, the aft one that you can see faces out to keep water out, the inner one faces the opposite direction and is for keeping the oil in the drive.
I would say the the inner seal is leaking.

Re: Leaking prop seal, seal installed correctly?

Thanks Don. Looking at the manual, it looks like several special Volvo tools are needed to pull the prop shaft and housing, so I'm not sure I want to take this on. Is there any safe way to pull both seals out from the front and reinstall the new seals without prop shaft removal?

Re: Leaking prop seal, seal installed correctly?

Oh yes, and it takes those special tools.

Are you sure it's not the oring on the drain plug leaking. Never reuse them, they tend to get little chunks cut out of them when removing.

Re: Leaking prop seal, seal installed correctly?

The drain plug has a new o ring on it and I can see the oil building up on the lip above it where the seal is(visible in the pic), so pretty sure it's the seals.

I did see one post on this forum from a couple of years ago where someone drilled and put a screw into the seals and was able to pull them out and replace them, but I know that's not the proper approach. Still somewhat tempting since metal shaving tend to be pulled out of a hole when drilling, and there should be room not to damage the shaft.

It looks like the cost of the tools is about the same as the 3-4 hours labor to have it done, so may need to let a pro handle this one.

Re: Leaking prop seal, seal installed correctly?

dacarter said:

I have receipts showing these seals were replaced 2 years ago, so not sure what's going on. I had the out drive professionally pressure tested a couple of weeks ago and they said it held 15psi for over 10 hours, and held vacuum.

Click to expand...

ask the shop to pressure test the leg at lower pressures, around 6psi. When my prop shaft seal failed it held at 15psi, but dropped like a rock at lower pressures.

Re: Leaking prop seal, seal installed correctly?

I decided to let the pros have a shot at this one, since several special tools are required. The shop that did the pressure test that didn't catch this leak, is going to do a complete lower unit reseal for 3 hours labor(90/hour), one hour off the regular labor charge for this job.

Re: Leaking prop seal, seal installed correctly?

So here's what the shop is telling me, and I tend to believe it since they seem to be very carefully accessing the situation and have many years experience...

The outer prop seals are ok and the leak is being caused by worn bearings allowing the prop shaft to sag slightly when sitting with the weight of the props pushing down on it, which slightly opens up the seals and allows some oil to escape. They showed me the parts disassembled, and there is light water damage on the bearings, not rust but barely visible marks on the races. They will put in a seal kit, but also replace the lower unit bearings. There is also some slight seal damage on the inner shaft and some slight corrosion on the outer shaft that they will hone out or send to a machine shop if they can't fix it.

Anyone ever seen this happen?

Re: Leaking prop seal, seal installed correctly?

It's now 5 weeks later, still waiting to get the boat back. What a pain. I'm looking at close to $600 in lower unit bearings and about $700 in labor. Sure hope they get it right.

No feedback on the diagnosis from the shop above?