outdrive hydraulics problem

[okielaker]

2008 272 with VP DPS-A sterndrive.

The hydraulics for the sterndrive trim "bleed" somehow, allowing the
outdrive to move to the full forward position over 10-30 minutes
of forward cruising. I can re-trim to further back position, but
after a while, I have to do it again. Have done this enought times
to run the reservoir dry if I was pumping fluid out, I believe.

No evidence of leaking fluid, anywhere. Watched closely as outdrive
was trimmed up and down on lift.

I think the leakage must be internal, but don't know were to start...
cylinders, pump, or manifold. The pump is located starboard of the
sterndrive (outside the bilge, rear of boat).

Rebuild kits for the cylinders and pump are available, as are whole
new parts. Apparently, all this is serviceable by someone of my
limited (but fearless) experience.

Looking for advice from anyone who may have experienced this, or a
similar problem, or who may have rebuilt any part of this system.
Is there a way to isolate which part the leak is in, or am I stuck
with just changing out or rebuilding parts until the leakage stops?

Unless it gets worse, I will probably wait until the season is over
to tackle this... boat is on the lift right now, and I won't be taking
parts off over the water... haven't actually viewed the reservoir, yet.

Picture of the location, hydraulic lines for outdrive trim. Pump is
behind the lines, reservoir underneath the pump (according to the
diagrams I've been able to pull up).

20200903_171952.jpg

[cmattj]

Your on the right track as high pressure fittings can leak under extreme load, and not just up and down on the trailer or lift.

Considering the stress is trimmed up, and cylinders extended... it will be difficult underway to see the “ oil sheen “ on the water at speed.

The swedge were the rubber and fitting are assembled Is a common Leak.

Even if you see a sheen form in the water when your operating the drive up and down ( engine off ), it may be hard to locate underwater.

Unfortunately when it’s not visable you may have to just throw new lines on it and try again.

[okielaker]

Matt, are you recommending that I change out the hydraulic lines for starters?
Hadn't really thought about that.. but sounds like an idea.

[cmattj]

Matt, are you recommending that I change out the hydraulic lines for starters?
Hadn't really thought about that.. but sounds like an idea.

As common for trim cylinders to leak this is is also a high pressure area as well. Operate your several times (make sure your voltage is up and just a few times is plenty ) and wait to see any collection of fluid after awhile. Under the trim ram or at the fitting block where the lines are connected.

Hopefully on a trailer and completely dry so you look in carefully.

Sometimes if nothing is noticeably leaking you got start throwing parts at it. I prefer when things are a bit more broken

keep us posted!

[Big Block Power]

Those junction blocks used to leak a lot. So watch that but yours look dry

[Eric55AMG]

I had a similar problem on my port outdrive (8.1 with DP duoprop).

No external leaks, so I wound up rebuilding the rams.

VP uses a poor design on one of the internal seals (it's actually a 2 piece design) that will eventually start allowing internal bypass resulting in a leak down of the ram.

I bought two different rebuild kits online ... one of the kits was "oem", while the other replaced the two part seal with a one piece replacement.

I wound up using the one piece replacement and have been very happy with the results.

It's a relatively easy job ... Hardest part on mine was getting the blasted retainer ring out in order to start breaking the cylinder down.

If you have an older cylinder ... It may just have a spin on end cap that can easily be removed with a spanner.

[okielaker]

I had a similar problem on my port outdrive (8.1 with DP duoprop).

No external leaks, so I wound up rebuilding the rams.

VP uses a poor design on one of the internal seals (it's actually a 2 piece design) that will eventually start allowing internal bypass resulting in a leak down of the ram.

I bought two different rebuild kits online ... one of the kits was "oem", while the other replaced the two part seal with a one piece replacement.

I wound up using the one piece replacement and have been very happy with the results.

It's a relatively easy job ... Hardest part on mine was getting the blasted retainer ring out in order to start breaking the cylinder down.

If you have an older cylinder ... It may just have a spin on end cap that can easily be removed with a spanner.

OK, Eric, thanks. Is there an easy way to diagnose this? Or is it just the lack
of a detectable external leak that leads one to rebuild the rams?

[Eric55AMG]

Just the process of elimination.
My outdrives would never leak down without a load.
When on the lift or trailer, I could have the outdrives trimmed up and they'd never drop (even after days), but once in the water and moving ... The port would leak down after 3 - 5 minutes or so.
I'd constantly have to watch the digital read out of the drive position and give the port a few "bumps of up" to bring it back equal to the starboard angle. Now they both stay locked where I set them.

[okielaker]

Just the process of elimination.
My outdrives would never leak down without a load.
When on the lift or trailer, I could have the outdrives trimmed up and they'd never drop (even after days), but once in the water and moving ... The port would leak down after 3 - 5 minutes or so.
I'd constantly have to watch the digital read out of the drive position and give the port a few "bumps of up" to bring it back equal to the starboard angle. Now they both stay locked where I set them.

That leak down you're describing sounds just like my problem. I'll check into the kits.
Do you remember where you sourced the better kit?

[Eric55AMG]

https://www.freewebstore.org/vp-outdriv ... 09838.aspx

This is the kit I wound up going with and was very happy with

[Eric55AMG]

Here is the other kit that I purchased.

https://www.ebay.com/itm/VOLVO-PENTA-Tr ... 890.l49292

I actually bought this one first ... Primarily because it came with all the key parts, including the steal retainer ring I needed for my cylinders ... But as I read more about how to do the job, I learned about the 2 piece composite seal that was prone to failure.

I did more research and found the kit in my earlier post with the replacement 1 piece seal that is better.

Between the two kits, I fixed one outdrive.

If I have to do it again, I'd just buy the first kit ... Especially now that I know how to remove the retainer clip in order to get they cylinders apart.