Trim ram burst

[pscott66]

I have a 1972 (I think) 165 Mercruiser straight 6 with a MR sterndrive. About a month ago (I have no idea why) the port trim ram just burst. I was trimming down a little and bam! it blew the cap right off. I got her home, bought a new cylinder, installed it, was moving it up down up down to bleed the lines ( this older system, I was told< is self bleeding) and all of a sudden POP! the side of the new cylinder burst open. I don't think I reversed any lines, however I did try undoing both lines, now if I plug off the up line and ask my wife to press the up buttons, the other ram goes up, and I get fluid out of the unplugged down line. Same result in the other direction. I have popped 2 $150 trim cylinders now and I am totally lost. Even the boat mechanic that I by my parts from has no suggestion.

Any help or insights would be greatly appreciated.

 

[alldodge]

Re: Trim ram burst

:welcome: to iboats

Where are you buying your trim cylinders, from what manufacture? Also what is the part number of the cylinders you are buying?

 

[achris]

Re: Trim ram burst

Hello and :welcome: to iBoats....

When you trim it UP, do you run it all the way and stall out the pump? If you do, then that may account for the blown rams. The UP pressure is in the region of 2600psi. But that pressure is only developed when a load is applied. Until the load that 'pressure' is translated into the ram moving. If you are getting more than that pressure, you may have a stuck check valve in the pump...

The reason the oil comes out of the DOWN hose when you trim UP is because the fluid on the aft side of the piston is displaced by the piston moving up. When the hose is connected that fluid returns to the pump reservoir.

Was the 'new' ram new or a second-hand one?

Chris.........

 

[Bt Doctur]

Re: Trim ram burst

your supposed to let the rams hang down .additional height can be obtained with a ramp. cycle them out, checking the oil level,
cycle them in , checking the oil lever.

 

[jabfd]

Re: Trim ram burst

sounds like its your reverse lock up valve mounting on the transom by the steering shaft

 

[alldodge]

Re: Trim ram burst

You could have a possibility of blowing a real old ram but not a new one. The ram is desigend to withstand the pressure, either real cheap non-equivilent parts or something else is in the mix.

 

[Bondo]

Re: Trim ram burst

sounds like its your reverse lock up valve mounting on the transom by the steering shaft

Ayuh,..... Exactly,.... Been there, done that,....

It has to be shifted in-sync with the controller, 'n the trim pump,...
By-pass it, 'n the Blown rams is the result,...

 

[pscott66]

Re: Trim ram burst

First I wanna thank everyone for the great idead .. so .. yes the reverse lock out has been disabled, the 2 blue wires are hanging, and I have no idea where to reconnect them.Also there is a tilt sender mounted on the transom, one of the high presure hoses is connected to it and heads out to the distrabution block under the drive. And there is a low preasure hose (no clamps or nothin) goes between the sender and the trim pump . I downloaded a complete set of merc manuals ( haven't had a chance to look st them yet. So could be the check valve, could be the reverse lock out ( I have to reconnect this any way, and figure why it was disconnected in the first place ), could be the trim sender assembly. Side note ... when I emptied the pump, the oil was like cold vegtable oil ( yuk ) clumpy and white and gross ...