Volvo Penta Trim Cylinder issue

[Nievo]

Tried to take the boat out yesterday for the first time and realized I could not get it to trim all the way up or down. Checked the fluid and it was low so I added some and did the 5x up and down to bleed it. Unit would still not go all the way down, was acting like it was hung up on something. Decided to check and see if it was the unit or the cylinders/pump. Unhooked one side and a time and ran it through a cycle. Left side went all the way up and down no problem. Right side will not go all the way down, gets to within the last couple inches and the cylinder acts like it is plugged/jammed.

Both the cylinder and pump are stupid expensive units. Any way to tell for sure if the pump for that cylinder is bad or if there is something wrong with the cylinder? Any other things I might be missing that it could be?

 

[Nievo]

Just disconnected both cylinders. Left one is firm and doesn't have much play when I try and push it in or out. Right one has about 2-3 inches of "quishy" play in it. Right one does not want to move in or out when I run the trim.

 

[Scott Danforth]

Pull the cylinder cap and look to see if there is any damage

A rebuild kit for the cylinders is reasonably cheap

 

[Nievo]

Just disconnected the hoses from the right cylinder and no fluid came out, even when I run the trim. Disconnected the hoses from the left side and was blasted with fluid.

 

[Nievo]

Pull the cylinder cap and look to see if there is any damage

A rebuild kit for the cylinders is reasonably cheap

Are you referring to the piece you have to push down to get to the lock ring in the rebuild video's?

 

[Scott Danforth]

I don't know what you are talking about. I don't watch videos. Not much to a hydraulic cylinder. The gland is threaded in and needs a pin spanner

 

[Nievo]

I don't know what you are talking about. I don't watch videos. Not much to a hydraulic cylinder. The gland is threaded in and needs a pin spanner

I think maybe we are thinking of different cylinders. These are on a Penta SX-A and don't seem to have a normal cap to pull.

I did remove both cylinder and run the trim. Fluid squirts out of the left side no problem when I run up or down but nothing comes out of the right side. Am I correct in thinking that each side has a different pump that runs that side and the pump is bad?

 

[Scott Danforth]

No, one pump, the cylinders are plumbed together

 

[Scott Danforth]

Here is the rebuild kit. https://five-star-marine.myshopify....6z6v3CgkhukxzV8AVZI0iXWlN01o4MU_H8svsHzkwTLPb

 

[Nievo]

Mine is the sx-a, not the sx. Not sure if that would make a difference with the pump or not but the rebuild kit is different.

Why would fluid come out one side and not the other with the cylinder disconnected though if it's not the pump?

EDIT: I just looked them up and the SX-A and SX do have completely different pumps.

 

[Scott Danforth]

Failed line, debris in the line, etc. a variety of reasons

 

[BRICH1260]

Sounds like a clogged line. Might try to clear by removing and blowing air through it.

 

[Horigan]

Yep. Blow air into the left cylinder lines and it should come out the right cylinder lines.

 

[Nievo]

Failed line, debris in the line, etc. a variety of reasons

Kinda my dilemma though. Do I just replace the cover with the newer version and new lines, or replace the whole unit. About a $300 difference

 

[Nievo]

I will try clearing the lines. Just weird that it would be both lines on that side. I couldn't get fluid to come out of either one going up or down.

 

[ESGWheel]

I will try clearing the lines. Just weird that it would be both lines on that side. I couldn't get fluid to come out of either one going up or down.

I am going to suggest you have a failed right side cylinder and it spewed debris (like a chewed-up O-ring) and that in turn has clogged the lines. Another alternative is that the hyd lines themselves are the issue > by delaminating its possible they collapsed internally. I think this is less likely as 2 internally collapsed lines at same time is not likely. That said I am bothered by hyd pressure not spitting out that debris when they were disconnected, and you ran the trim pump up and down.

My suggestions:

• Tackle the trim cylinder first, ie do a rebuild on it. Suggest making sure you know what kit is needed and its lead time and take apart the cylinder first > you may find it is not rebuildable.
• For the lines, get new ones. If they are clogged so badly as to resist clearing under the hyp pump pressure they probably have internal damage and while you may get them clear, they may burst on you later.

Also, when getting the new lines make sure you get some extra O-rings > those little suckers are easy to lose or damage. And do not overtighten the fittings. Its something like only 7 to 9 foot pounds if I recall correctly. That is not much at all and if you are not familiar with how much force that is, suggest this: get an inch-pound wrench like this (link). Set up an arrangement where you tighten a 7/16 head bolt to 96 in-lbs (which is 8 ft-lbs). Now take that 7/16 flare nut wrench you will use on the fittings and tighten that bolt just a little more. Do this a few times and you will get the feel of what it takes. Its not much!

Good luck and keep posting question / updates.