Re: Trim Cylinder Seal Kit Needed
all but three seals are standard orings. The ideal material is Viton since it will resist chemical additives. Except for 1988-1992 Prestolite you can use the same hydraulic oil as any bucket truck or bulldozer. 1988-1992 needs a thicker fluid to smooth out the down cycle on bigger engines. For them non-detergent 30W motor oil is ideal.
The piston shaft wipers are not standard o-rings. The tilt and shock use a poly scraper and the trim uses a brass scraper with rubber seal. Sometimes, but not always, the trim piston shaft o-ring should be replaced with a square ring to assist with sealing.
Regarding trim, tilt, & shock. They rarely leak down unless chemical additives have been introduced. The additives attack all seals equally. More often than not, if any of the slave cylinders leak down then the entire system should be rebuilt. This is especially true if you have an engine made by Mercury (early 90's). Even though manufacturer clearly says to use oil in their pump Mercury went cheap and used ATF (reddish colored fluid). When the trim ram fails on a Mercury made engine it is almost mandatory to have the pump rebuilt also.
If your system was made by Chrysler, Force, or USMarine then your rams rarely fail and bleed down is almost always fixed by a simple pump rebuild. Inspect your top seals on tilt and shock. If the plastic is still scraping off water and debris then your ram is 99% sure to be okay. If the plastic scraper is torn or cracking then ram should be rebuilt as soon as possible (before water gets in and rusts out your bypass springs). If you system is Mercury with Eaton pump and bleeding down then you should consider a complete overhaul. The Eaton pump usually doesn't fail until cheap atf starts causing trim rings to crumble.
