Showa trim unit issue

[Joker CCT]

Tried searching but couldn't really find a solid answer so I was hoping someone here could help.

Recently rebuilt the trim tilt unit on my 07 yamaha f150 due to leaking seals on the trim and tilt pistons. Finished everything up and was able to bleed without issue. I had noticed initially, that while trimming down that the trim portion lets the motor down very slow compared to the other motor(10 sec slower to be exact). Also while tightening one of the trim caps there was a little resistance then i heard a small pop and the cap continued to thread on normally, almost like pressure building and releasing internal the unit. On the first water test coming off the trailer, while in reverse with any amount of throttle the motor kicks up. This did not happen prior to the rebuilt so I'm assuming I assembled something incorrectly, possibly the tilt piston sub assembly. I haven't taken it back down yet but I will hopefully sometime this week. If someone can give me some insight on this it would be greatly appreciated. Thank you.

[Keithbaja]

Nothing should ever POP... Myself quite rebuilding them. Too much time and Pain in the a$$. Remans or new for my Customers,, plus a warranty that I don't have to deal with..you know what they say.. " work smarter,, not harder"

[DennisG01]

Could the pop have been misaligning the cap with the threads and instead of buggering up the threads you got lucky and it just popped back on the right way? Other than that, there's no reason for a popping noise screwing that cap on unless something was not put back together correctly.

The tilt function always goes faster than the trim function.

I completely rebuilt mine - there are a TON of little balls and springs and seals. I'm glad I did it... 'cause now I know why I'll never do it again! I'd rather buy a rebuild from someone that does it for a living. But, yes, it sounds like you get to do a "re-do"!

[Joker CCT]

Could the pop have been misaligning the cap with the threads and instead of buggering up the threads you got lucky and it just popped back on the right way? Other than that, there's no reason for a popping noise screwing that cap on unless something was not put back together correctly.

The tilt function always goes faster than the trim function.

I completely rebuilt mine - there are a TON of little balls and springs and seals. I'm glad I did it... 'cause now I know why I'll never do it again! I'd rather buy a rebuild from someone that does it for a living. But, yes, it sounds like you get to do a "re-do"!

Yeah, so that was my initial thought on the pop, I unscrewed the cap to verify and both the cap and cylinder threads, they both looked good. When I tore the trim unit down I only replaced seals on the 3 caps and pistons. The only thing to really screw up on there would possibly be when I disassembled the tilt rod assembly, the check balls and springs inside of that. I will pull it back down to verify.

Referencing the speed the tilt goes down was in comparison to the other motor, (twin f150s). Another symptom is the trim rods will not retract inside the cylinders if you flip down the mechanical lock and hold the trim down button. I guess that is the correct way to store motor when not in use to prevent pitting on the trim piston shafts.

[Keithbaja]

Use OMC Triple guard grease to hold all those lil balls in place

[Joker CCT]

Thank you to those that have taken the time to respond. I just wanted to give an update and close out this thread.

So I went back and removed the tilt pistons on both motors to compare, since I had one unit working properly and one that was not. I only removed the tilt piston assemblies not the two trims. I disassembled both and tilt piston assemblies and there was no issue with how the assembly was assembled when I replaced all the seals. What I did find was that once I opened the manual release screw on the unit with the issue, with the tilt piston removed, you could see the fluid level drop drastically. I cleaned everything back up and reassembled the tilt pistons carefully adding fluid and making sure the cylinder was full when replacing the piston and cap. After everything was tight I rechecked and had to add a little more fluid but the unit now functions properly. In conclusion, my best guess is that there was a large pocket of air trapped inside the unit that was not going to bleed out by raising and lowering the motor.