Ram cap blown apart

bobsboat

Recruit
Joined
Jul 1, 2004
Messages
2
Mercruiser 4 Cyl. I/O Model 1 (pre 1983) rams rebuilt 3 months ago with new shells, piston, o-rings,inner tube, and NEW caps. Installed and worked fine(about 12 up & downs). Sat up out of water for 3 months with no use waiting for lower unit repairs. Today, installed lower unit and tried to lower OD, moved down real slow, went up ok for 1 or 2 seconds then POW, new end cap blew apart. The oil lines are NOT crossed, tho OD was only 1/2 way to full up position, and OD moves freely with rams disconnected. Took ram apart and put old cap back on. Guess what? Same thing happened exactly, OLD ram cap blew apart on way up to 1/2 up position. <br /><br />Any suggestions as to cause and repairs to fix this problem. I only have one more cap and don't want to blow it apart like the others.<br /><br />Thanks for any help!<br />PS I'll post a picture if someone tells me how.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Ram cap blown apart

Hi Bob,<br /><br />Hell of a way to enter this forum! Welcome anyway...<br /><br />Have you checked the adjustment of the reverse lock valve and reverse inter-lock switch? The valve is to stop the leg tilting up when reverse gear is selected by closing the return line (or down presure line) and the inter-lock switch stops the pump being run 'up' when reverse is selected. If the valve is closed and the pumps runs 'up' you'll get a build-up of fluid 'under' the cap. Could easily cause your "POW".<br /><br />Chris............
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Ram cap blown apart

Bob,<br /><br />Try having a look at this hydraulic flow drawing. The reverse lock valve is item #16. If it's closed and you run the trim 'up' then you'll see the pressure will build up in the system. I would have expected a hose to burst, but you got a cap that goes "POW". <br /><br /> http://www.myfishingpictures.com/showphoto.php?photo=25078 <br /><br /><br />Chris............
 

bobsboat

Recruit
Joined
Jul 1, 2004
Messages
2
Re: Ram cap blown apart

Chris <br />Thanks for a prompt response. now I think back.. just prior to lowering OD I WAS adjusting the lower shift cable as I also changed out all control cables. I could have left the shifter in reverse, causing the reverse lock valve to be closed. I'll check for that possiblity this AM.<br /><br />Bob
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Ram cap blown apart

Bob,<br /><br />AND????<br /><br />Chris..............
 
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