How to repair / rebuild trim cylinders?

[Fordiesel69]

1978 Sear Ray SRV 195 w/ MC-1:

Found both trim cylinders to be faulty one last summer, and one this summer. They will allow the drive to go up, but when trying to lower the drive the trim pump runs like it has air. After swapping it works like a champ. What inside these cylinders needs repair or rebuilt? Are there some kind of check valves that jam up? The ones that do not work are in excellent cosmetic shape, the working ones that I put on are corroded and have 30 coats of paint on them.

New replacements are out of the question.

 

[ThndrSki]

I'm not sure about your year or model, but I would start with getting the factory service manual, as the FSM for my alpha I has a great procedure listed. To repair, it is basically just a seal kit as long as your rams/plunger isn't too scarred up or corroded out.

I just ordered seal kits for my trim rams for less than $20 a piece. On the Alpha I trim rams, the only special tool you might require is a "Spanner Wrench" with the little dowel ends to fit into the dimples on the end caps of the cylinders. You put the wrench in there, spin off the encaps and can access all the innards.

The FSM is a great guide as it keeps you from making "stupid" mistakes doing it the first time.

 

[Fordiesel69]

The model and year is listed above.

The problem is not leaking seals, but a problem is which the cylinders lock up the up position and the trim pump is unable to lower the drive. It is like a valve or somthing is keeping the fluid from flowing.

 

[ThndrSki]

There is a check ball/valve in the trim rams. Like I said, my advice if you're going to tackle yourself is get the FSM. It's the only way to know you're doing it right.

If not, these guys are pretty reasonable for new trim rams. I almost just bough mine new instead of rebuilding: http://www.sterndrive.cc/

 

[Scott Danforth]

change your fluid. the trim pump PSI for lowering is only about 90 psi (because it gets help from the prop), and about 4 times that to raise.

usually a fluid change is all that is needed to get the dirt out of the reservoir.