1975 Mercruiser Tilt/trim issue

[rogerrabbitis]

Hi so end of last season my tilt / trim system was pretty much out of fluid I seem to have a leak I can't find it seems to be in the boat not outside as I don't see any oil in the water but this year we failed up the system and we can get it to go up but not down we have tired to purge the system but still having the same issue I think there is still an air lock but not sure how to get rid of it any ideas ? also options to find the leak I was thinking of dye in the system to help find where it may be leaking from ?

 

[Scott06]

Hi so end of last season my tilt / trim system was pretty much out of fluid I seem to have a leak I can't find it seems to be in the boat not outside as I don't see any oil in the water but this year we failed up the system and we can get it to go up but not down we have tired to purge the system but still having the same issue I think there is still an air lock but not sure how to get rid of it any ideas ? also options to find the leak I was thinking of dye in the system to help find where it may be leaking from ?

Yes for leak detection UV dyes can be a life saver. I got a cheap UV light off amazon and different dyes for AF and Oil, found some leaks more easily than I would have, but you have to clean it all up with brake fluid firts.

I would stand on the drive or disconnect the trim rams to see if its a hydraulic issue or a drive is tuck issue. Lilky crud in the seals

 

[kenny nunez]

As Scott06 posted about standing on he drive to see if that helps to bring the drive down. There is up to 3000 lbs of pressure to raise the drive and only 7-800 lbs on the down circuit. The packing inside of the end of the rams get a build up of crud that most times restricts the down movement.
If this is the problem the rams have to be rebuilt. With the drive raised you can try some penetrating oil on the ram. That might work to loosen the crud build up by raising and pushing down on the drive.
Put your hand under the bottom of the pump, that is where the leak may be. With a 3/8” wrench tighten the high pressure line, they tend to loosen up over time.

 

[rogerrabbitis]

thanks for the tips I will look in to that UV dyes we had disconnected all the lines to purge the system of any old fluid and to try to get rid of the air and I moved the rams up and down no issues they moved freely

I tired last night to force the drive down pushing down on it. I heard the diverter valve down at the bottom of the pump gets stuck and I read you can push down and force it to unstick it that did not seem to work and I can't seem to get it down now

I heard there is a Pressure release valve where would I find that ?

also on the rams there are two lines at the back one closer to the stern and other a by it witch one of those are up and down ?

 

[kenny nunez]

The lines close to the stern should be the high pressure for up. The rams are not left and right, always the most forward port on the rams is for the up circuit.
Do not look for any type of release valve.
If you had a pressure gauge that goes up to 1000 lbs you could test the down circuit pressure. There is an adjustment if your pressure is less than 500 lbs but it is very sensitive.
Is your pump mounted to the transom plate or mounted to the deck?

 

[kenny nunez]

The lines close to the stern should be the high pressure for up. The rams are not left and right, always the most forward port on the rams is for the up circuit.
Do not look for any type of release valve.
If you had a pressure gauge that goes up to 1000 lbs you could test the down circuit pressure. There is an adjustment if your pressure is less than 500 lbs but it is very sensitive.
Is your pump mounted to the transom plate or mounted to the deck?

 

[rogerrabbitis]

The lines close to the stern should be the high pressure for up. The rams are not left and right, always the most forward port on the rams is for the up circuit.
Do not look for any type of release valve.
If you had a pressure gauge that goes up to 1000 lbs you could test the down circuit pressure. There is an adjustment if your pressure is less than 500 lbs but it is very sensitive.
Is your pump mounted to the transom plate or mounted to the deck?

so there is no pressure release valve ?
My pump is mounted to the transom plate

 

[kenny nunez]

Contact West Marine with part #18-2142. Hydraulic ram. They have a close out @$51.42. Normally these rams cost over $300.00.
The “O” ring repair kits are very hard to find as they are NLA.
This is a killer deal and If they have them you better jump on it now!