Spring Projects Part 1 - Fixing The Trim Reservoir

[MikeB]

With the nice weather I thought I would get a jump start on some CVX-18 work.  Towards the end of last season the I noticed the trim occasionally wouldn't move the drive down.  Checking the pump I saw a huge amount of milky oil had leaked out of the reservoir.  As a quick fix I just re-filled the reservoir with 5W-30 & did the up/down/up with the bleed screw out to remove the air.  It would work fine after this, but then 3-4 outings later the trim would quit working again.  Also, after being left alone for a few days with the drive up the drive would slowly go down on it's own (not sure if this indicates a leak at the ram or just some water in the system.)  Repeat steps above a few times throughout the summer.  Before winterizing I believe we got all the water out. 

So now I'm trying to decide where to start figuring this out.  Seems like water is entering the hydraulic system while under load...  (a leak at the hose coupling maybe)?  I checked the hydraulic rams and don't see any obvious cracks.  I don't see anything leaking out when moving the drive up & down either.  Any tips on how to troubleshoot this?

It's a 1980 mercruiser 898

[Rich_V174SS]

Water enters the system from around the seals in the end of the pistons where the ram comes out. When the drive is lowered and the piston retracts it draws water into the cylinder through the cap seal.

[MikeB]

Water enters the system from around the seals in the end of the pistons where the ram comes out. When the drive is lowered and the piston retracts it draws water into the cylinder through the cap seal.

Sounds like I might be looking at re-building the rams with new seals?  Wonder if I can find someone local to do it.

[75starflight]

There really simple once you get into them mike. I tore down a spare set I had laying around just to see how they tick since I have to reseal the cylinders on Phoenix. They started having a settling issue at the end of last season.

Oh, I picked up the kits for $22 each off ebay.

[Neutron68]

Hi Mike, how did this leaking trim reservoir play out? 
Given the milky oil in the engine area of your boat, did the reservoir need parts replaced?

Eric