cobra sx trim cylinders are leaking down after a short period

[123landrover0]

I have a 97 glastron 175 with volvo penta outdrive(cobra sx),the outdrive drops after about a half hour.I have no fluid leaks inside where pump is and completelety dry outside.I am leaning toward the pump trim assembly but i am not 100% sure,steve

 

[55evinrude]

Re: cobra sx trim cylinders are leaking down after a short period

could be bad trim ram seals, somewhere in the system air could be getting in, trim fluid could be low.

Nathan

 

[Senior B]

Re: cobra sx trim cylinders are leaking down after a short period

There are several areas that can cause this and you've eliminated a couple of them saying you have no external leaks. It is now then an internal leak from with-in the pump, likely the trim up check valve or an internal leak from an unseated impact valve or bad piston rings in either of your trim cyls. I would bring the drive all the way up and mark the resevor/check your fluid level. Let it sit and bleed down. If the resevor level is up, problem is in the pump (check valve). Level the same, fluid is by-passing with-in the trim cycl. There is a seal kit available to replace all seals and piston rings but if the problem is a bad impact valve contained in the piston, you'll have to replace the cyl. If you get a manual, it will show you a break down of the pump and where the check valves are. There is no repair procedure for the trim cyl themselves so most just replace them but there are many threads here on the forum that address how to do it and have the part number for the seal kit.

 

[123landrover0]

Re: cobra sx trim cylinders are leaking down after a short period

There are several areas that can cause this and you've eliminated a couple of them saying you have no external leaks. It is now then an internal leak from with-in the pump, likely the trim up check valve or an internal leak from an unseated impact valve or bad piston rings in either of your trim cyls. I would bring the drive all the way up and mark the resevor/check your fluid level. Let it sit and bleed down. If the resevor level is up, problem is in the pump (check valve). Level the same, fluid is by-passing with-in the trim cycl. There is a seal kit available to replace all seals and piston rings but if the problem is a bad impact valve contained in the piston, you'll have to replace the cyl. If you get a manual, it will show you a break down of the pump and where the check valves are. There is no repair procedure for the trim cyl themselves so most just replace them but there are many threads here on the forum that address how to do it and have the part number for the seal kit.

great in theory but this reservior is black and the only way to check it is to unbolt it ,tip it horizontally and pull a plug out.Steve

 

[wildboater]

I've got a 1991 5.7 doing the same thing. I intend to do the following troubleshooting per a blog elsewhere on the net:

Raise the outdrive to full up
Drop it down a couple of inches
Take the top cylinder hydraulic lines off both trim cylinders (pans underneath to catch fluid)
Watch the openings once the initial fluid clears
If fluid comes out of the port cylinder, it's causing the leakdown
If fluid comes out of the starboard cylinder, it's the culprit
If neither weeps fluid, it's the internal seals in the trim pump

I suspect my port cylinder, but I'll rebuild both if that's what it turns out to be.
Seal kits for the cylinders are about $50 each. Used cylinders, guaranteed not to leak run anywhere from $60 up to $200.

 

[wildboater]

I've got a 1991 5.7 doing the same thing. I intend to do the following troubleshooting per a blog elsewhere on the net:

Raise the outdrive to full up
Drop it down a couple of inches
Take the top cylinder hydraulic lines off both trim cylinders (pans underneath to catch fluid)
Watch the openings once the initial fluid clears
If fluid comes out of the port cylinder, it's causing the leakdown
If fluid comes out of the starboard cylinder, it's the culprit
If neither weeps fluid, it's the internal seals in the trim pump

I suspect my port cylinder, but I'll rebuild both if that's what it turns out to be.
Seal kits for the cylinders are about $50 each. Used cylinders, guaranteed not to leak run anywhere from $60 up to $200.