Re: Trobleshooting/repairing trim cylinders on mercruiser 470 outdrive
well, first, the older 470,s came with borg warner transmissions and TRS outdrives.
does your boat still have the seperate transmission / outdrive system or is it a bravo set up?
i love the TRS outdrives, they are as tough as nails.
second, if the trim cylinders wer broken off as a result of the outdrive being pushed past their limitations, im thinking the pistons are the least of your problems
testing the pistons is easy. just disconnect them from the drive, remove the anodes, and have someone activate them while you watch to see of the shaft is bent, or if any fluid leaks from around the seals while going in or out.
if its leaking fluid, the shaft is probably bent even of you cant see it. replacing the seals wont help, but im pretty sure you can rebuild the entire assembly and replace the shaft.
second. if the drive was pushed beyond the limits of the actuators, you need to remove the drives.
you need to check the gimble for damage with the drive off, the transome around the gimble for stress cracks, and you probably need to realign the drive shaft as well.
third, if it hit the skeg, your probably ok, if it hit the props however, you should also check to see of the prop shaft is bent. easy enough to do, just remove the prop and start the engine. put it in gear adn look for wobbeling or fuild leakage around the shaft seal.
i smacked my twin TRS drives against something submerged in the water hard enough to lift both of them out of the water and take the boat off a plane. a 9000 lb donzi going about 45 mph.
after removing and checking everything, it cost me about 400 bucks to have a new skeg welded back on one of the drives and 150 to streighten a prop. tough as nails i tell you. my brovo three would have cost me thousands to fix under the same circumstances.
good luck. if its a TRS, you probably stand a better chance of destroying your gimble and transome than the drive.,