Trim cylinders leaking down

[cameron92]

How can I pinpoint where the pressure is not being held, drive will fall completely to the ground in about 5-10 mins.

I ordered 2 cylinder rebuild kits but now I'm wondering if those are even needed, could the leak be happening in the pump? Where do they commonly leak?

 

[kenny nunez]

The only way is to get a pressure gauge that reads up to 3000 psi and connect it directly to the high pressure discharge port .i know it takes some creative plumbing. NAPA sells 3/16” made up steel tubing with flare nuts in short lengths. You will have to get the fittings to mate to the gauge.

 

[pattyson]

How can I pinpoint where the pressure is not being held, drive will fall completely to the ground in about 5-10 mins.

I ordered 2 cylinder rebuild kits but now I'm wondering if those are even needed, could the leak be happening in the pump? Where do they commonly leak?

I'm back working on my 84 3.8l omc stringer... been down for a year, GF says two lol.... anyways... mine was leaking down a lot like yours. I added fluid a couple of times to replace my transom seal.... a year or two ago..... finally got the right seal a week ago after a couple mismatched ones, short story... I bought more ATF cause I new it was leaking down.... well I hit the trim button figuring it was empty and wouldn't work. But amazingly it worked fine and hasn't leaked down in a day. I took a look at the new ATF I bought and it said it had stop leak in it. So maybe when I added the fluid a year or two ago, it might have had stop leak in it and worked?? I donno, just throwing that out there.

 

[Scott Danforth]

Hydraulic seals last about 15-20 years

Most like the piston seals are leaking and bypassing the piston.

Easy test, lower outdrive, pull the up hose, then press down. If the piston seals are bad, oil will come out the ports up ports in the cylinders