Trim cylinder hose replacement

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Sep 27, 2024
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Hi all,

I'm new here but have used the forum a ton while working on the outdrive of my boat (2007 Chaparral 210 SSi - Alpha One Gen 2). Amazing content and extremely helpful people here.

Onto my issue(s) - My outdrive was showing quite a bit of paint flaking/some corrosion so I've undertaken a maintenance and refinishing job.

My current hiccup (the job seems to get bigger by the day) is in regards to the trim cylinders/rams. I went to remove them to refinish them and as I was draining them realized that the fluid looked like it had water intrusion. First question is - what is the most likely culprit here, the seals on the cylinders themselves? The trim seemed to function just fine and never realized any leaks or fluid levels dropping at the reservoir to any noticeable degree.

Next, I had a real time getting the hoses off of the port side cylinder (ie I couldn't, tried everything - heat, PB blaster, myriad of wrenches/vice grips). The hoses looked like they could use replacing anyways so I just cut them and used a 6 point socket to remove them. I manually cycled the cylinders to get all remaining fluid out, cleaned them up/sanded and painted them. When I go to reinstall them, from what I've read you can purge the lines by simply cycling the trim up/down. Is this still the case if I've emptied the cylinders themselves or must I use another method to refill the cylinders (as I've read in the manual)?

Thank you in advance and happy to be a part of such a great forum. I'm sure there will be more posts to follow as I'm tackling many things I'm unfamiliar with!

Daniel
 

alldodge

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Welcome
Need to use a line wrench also called flare nut wrench to remove the lines

No need to prefill cylinders or bleed them. Install and run them up down several times trying to make sure reservoir does not go empty. If it does go empty then just need to cycle more

The seals is where the water would come in
 

Drivewayboater2

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If you haven’t reinstalled the cylinders I’d replace the seals. seal kits are cheap and the job is relatively easy. If you had water in there from the start its gonna be in there int the future. good luck.
 
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Thank you for the prompt responses!

Welcome
Need to use a line wrench also called flare nut wrench to remove the lines

No need to prefill cylinders or bleed them. Install and run them up down several times trying to make sure reservoir does not go empty. If it does go empty then just need to cycle more

The seals is where the water would come in
Ahh yes the flare nut wrench would've been the way 🤦🏼‍♂️ even with the socket it was quite difficult to remove but I will definitely keep this in mind for next time. Is there anything I could apply to the fasteners without ill effect that will aid in removal in the future? Thank you!

If you haven’t reinstalled the cylinders I’d replace the seals. seal kits are cheap and the job is relatively easy. If you had water in there from the start its gonna be in there int the future. good luck.
Good call - I was considering this and then read there's a specialty tool. By the looks of it I might be able to use an adjustable grinder flange nut tool? Wasn't sure I could just purchase the seals individually but I am definitely going to look into this now, thank you!
 

Bondo

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Ahh yes the flare nut wrench would've been the way 🤦🏼‍♂️ even with the socket it was quite difficult to remove but I will definitely keep this in mind for next time. Is there anything I could apply to the fasteners without ill effect that will aid in removal in the future? Thank you!
Ayuh,...... Welcome Aboard,....... Quicksilver Perfect Seal, aka: form-a-gasket non-hardening liquid, #3,.....
I use it on pretty much every threaded fastener that I might want to take apart someday,.....
 
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Ayuh,...... Welcome Aboard,....... Quicksilver Perfect Seal, aka: form-a-gasket non-hardening liquid, #3,.....
I use it on pretty much every threaded fastener that I might want to take apart someday,.....
Thank you and thank you! So you would use this even on the bolts connecting the lower to upper, for example? I was thinking of putting some 2-3-C on them but wasn't sure if that's appropriate.

Also (since I have it on-hand), would permatex aviation form-a-gasket be an acceptable alternative to the QS perfect seal in this application?

Thanks again!
 

Lou C

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When I had a leaky trim cyl I was going to replace my originals with good condition used units from fresh water but I had the same problem one of the hydraulic fittings would not budge. So I backed away from it and thought it over. My original cyls were still in OK shape. If I could get the end caps off I could used the piston & rod & end mount from the freshwater units. So I made the sign of the cross said a few Hail Marys and heated the end of the cyls a bit and went at it with the pin wrench. And they came off! The cyls were very easy to rebuild after that. I knew if I destroyed that fitting I’d have to go thru the hell of getting the one inside the transom mount off to replace that entire trim hose. This way I avoided that and the tilt & trim system works perfect.
 

Lou C

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I have not done an Alpha but on the Volvo/OMC units the seal is made with an O ring on the trim hose metal end so you could use sealer on the threads of the fittings without it getting into the hydraulic oil…
 
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When I had a leaky trim cyl I was going to replace my originals with good condition used units from fresh water but I had the same problem one of the hydraulic fittings would not budge. So I backed away from it and thought it over. My original cyls were still in OK shape. If I could get the end caps off I could used the piston & rod & end mount from the freshwater units. So I made the sign of the cross said a few Hail Marys and heated the end of the cyls a bit and went at it with the pin wrench. And they came off! The cyls were very easy to rebuild after that. I knew if I destroyed that fitting I’d have to go thru the hell of getting the one inside the transom mount off to replace that entire trim hose. This way I avoided that and the tilt & trim system works perfect.
Sounds like a successful mission! I have an adjustable grinder flange nut tool and the first end cap came off SO easily (maybe part of the concern here even?) but the 2nd one won't budge. I have the cylinder in a bench vice even and using a hollow steel tube on the flange nut tool for leverage, not budging. I'm just bending the pins on the tool now! I imagine the end cap has some sort of "permanent" seal (aka not replaceable without replacing the entire end cap?) where the trim ram slides in and out of it? O-rings look easy enough to replace but I'm wondering if water can't get in where the rod actually enters the end cap itself?

Thank you for the input!

I have not done an Alpha but on the Volvo/OMC units the seal is made with an O ring on the trim hose metal end so you could use sealer on the threads of the fittings without it getting into the hydraulic oil…
There's no o-rings in that spot on these, from what I can see, it's a flared tube connection .. not sure if I'm making sense. Thank you!
 

Lou C

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Also forgot to mention; depending on the trim pump you have you may have to raise the trim all the way up before removing the fill plug. Not sure if Merc used the same or similar pump to OMC but that’s how mine is for sure; says it in both the shop manual & owners manual…if you don’t hydraulic oil can spurt out under high pressure. Raising the drive all the way up lowers the pressure in the reservoir….
 

Lou C

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Ah so Merc used a flare like a brake line then, I might not use sealer in that case. If you have the cylinder off & there’s no fluid in it heat the alu part where the threads are and put some ice on the cap itself for a few min…that might break it free…
 
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Also forgot to mention; depending on the trim pump you have you may have to raise the trim all the way up before removing the fill plug. Not sure if Merc used the same or similar pump to OMC but that’s how mine is for sure; says it in both the shop manual & owners manual…if you don’t hydraulic oil can spurt out under high pressure. Raising the drive all the way up lowers the pressure in the reservoir….
Great point! Luckily, I think by chance (and since I have the boat on the trailer) it's trimmed up all the way to begin with. I didn't have any high pressure issues in removing the lines, in fact very little fluid came out of the lines themselves when I removed them (and then none when I removed the lines from the block on the transom assy).
 
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Ah so Merc used a flare like a brake line then, I might not use sealer in that case. If you have the cylinder off & there’s no fluid in it heat the alu part where the threads are and put some ice on the cap itself for a few min…that might break it free…
Yes that's correct, just like a brake line. You think it's a concern that some sealer might get in the fluid if I put it on the threads?

I manually "emptied" the cylinders but when I got the first one open there was still a little bit left in there. Does this make heat a poor idea? Thank you!
 

alldodge

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Also (since I have it on-hand), would permatex aviation form-a-gasket be an acceptable alternative to the QS perfect seal in this application?
2-4-C is a lubricant and no issue with its use
Permatex is good

Don't worry about pressure build up in the reservoir because there isn't much if nay there, all pressure is inside pump and system
 

Bondo

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Yes that's correct, just like a brake line. You think it's a concern that some sealer might get in the fluid if I put it on the threads?

I manually "emptied" the cylinders but when I got the first one open there was still a little bit left in there. Does this make heat a poor idea? Thank you!
Ayuh,..... It doesn't take much, yer just trying to seal the ssteel threads from corroding into the aluminum housing,....
 
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Ayuh,..... It doesn't take much, yer just trying to seal the ssteel threads from corroding into the aluminum housing,....
Thanks Bondo! Anything to keep them from seizing like they were would be a plus 😅 Perhaps you could shed some light on this comment as it has me a bit stumped and unsure of parts I should be acquiring:

"I imagine the end cap has some sort of "permanent" seal (aka not replaceable without replacing the entire end cap?) where the trim ram slides in and out of it? O-rings look easy enough to replace but I'm wondering if water can't get in where the rod actually enters the end cap itself?"

Thank you all for your time!
 

Bondo

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Thanks Bondo! Anything to keep them from seizing like they were would be a plus 😅 Perhaps you could shed some light on this comment as it has me a bit stumped and unsure of parts I should be acquiring:

"I imagine the end cap has some sort of "permanent" seal (aka not replaceable without replacing the entire end cap?) where the trim ram slides in and out of it? O-rings look easy enough to replace but I'm wondering if water can't get in where the rod actually enters the end cap itself?"

Thank you all for your time!
Ayuh,...... I've never rebuilt a set of rams as new as yer's, so I can't say for sure,.....
Personally, I'd clean up what you got, replace the cut lines, 'n run it till you find the actual cause,.....
Something not discussed is I wonder whether the water didn't come from the hyd. tank itself,..??
I've seen a flooded bilge where water could enter from a loose cap on the pump's tank,....
 
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Ayuh,...... I've never rebuilt a set of rams as new as yer's, so I can't say for sure,.....
Personally, I'd clean up what you got, replace the cut lines, 'n run it till you find the actual cause,.....
Something not discussed is I wonder whether the water didn't come from the hyd. tank itself,..??
I've seen a flooded bilge where water could enter from a loose cap on the pump's tank,....
This might just be the route I end up taking, at this point. I'd say that's possible as the boat did sit unused for a while, though the tank itself is fairly high up from the bottom of the hull which makes me think it's unlikely water would've it made it that high. Thanks again!
 
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Just want to confirm what I've read is accurate - can I use this ATF for my trim fluid?

Thanks all again!
 

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