StrikinLightnin

I'm going to install new trim cylinders on a set of Bravo's
After I have the cylinders installed what do I have to do to
with the fluid to get them to trim in and out?
Do the cylinders have to be bled?
If so how?
This is one job that I've never done before.

Thanks

Falcon

Yes you should get them bled. The procedure is in a Merc manual somewhere, but there are a couple of basic ideas that help in getting the air out if the cylinder has no oil in it.

1) Keep the reservoir full enough that it never sucks air!

2) With the cylinders fully compressed, remove the line(s) at the cylinder that would extend it. In the case of the Bravo/Alpha drive trim it would be the lines closest to the transom on the cylinder. Aim the lines into a catch container and run the pump until you get solid fluid. Attach the lines. Because the piston is at the end that you are attaching the lines, there is very little air to be trapped in this end of the cylinder.

3) Some say that at this point you can just trim the cylinder up and down a few times, checking the fluid level, and the rest of the air will work it's way out. It may work it's way out, but it's better if you bleed out the trim in side too. It works better if when you put the cylinders back together that you pushed the rod in and pour some oil in the rod end side of the cylinder. That way when you trim out, oil is being returned to the pump. The pump is bidirectional and when pumping the first oil pumped out is what is returned from the other side of the cylinder. If there is air returned, it is sent back to the other side. What helps it eventually bleed out is that trimming the cylinder out needs more oil than what is being returned so the pump pulls in oil from the reservoir. When the cylinder is retracted again there is more oil returned than what is needed so the extra is returned to the reservoir. This unequal displacement can help to eventually work some air out. Not leaving this to chance, if you didn't fill the back side of the cylinder, you can do the following.

4) After bleeding the trim out line as in step 2, but before trimming out do the following. remove the trim in lines at the bottom connector block. Important: Plug both open ports on the connector block. This will keep the pump from pulling in air.

5) Trim the drive out, checking fluid level. If you did fill the trim in sides of the cylinders you just noticed oil running on the floor!

6) Remove the plugs. Carefully run the trim pump "IN" or "Down" until oil comes out the ports. Could get messy or you could put in a couple of extra lines and direct the oil into a catch basin.

7) Reconnect the trim in lines to the connector block.

8) Trim the drive in and set your fluid level in the reservoir. Notice how solid the drive trim is.

New installations have it easy. The cylinders are filled and bled at the factory including the lines. If you connect the stock lines at the pump and fill the reservoir there is nothing to be bled out. This is much simpler than it looks in text. Also, if you fill the cylinder with oil before (also pour some in between the main piston and the relief piston) you can avoid the last half of the instructions. I hope this helps. I think that it helps to understand how these systems work so you don't have to remember each step, just think about how you could go about keeping air from being returned to the pump.

Tinkerer

What I do and it is very easy. I install the cylinders but not the rod at the eye of the cylinders. Put a rag under the cylinder to keep it off the drive and just trim it in and out a whole bunch of times. The whole idea is to keep the cylinder level-- that way the air gets out. Works great. Just make sure to keep the reservoir full while doing this.