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Replacing pre alpha trim ram

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Phantomsculler

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Hi All. Can I replace a pre alpha trim ram (2 hydraulic input holes at the transom end) with an alpha 1 ram (1 hole at transom end and 1 hole underneath and facing down at the other end) ? I have read somewhere that the different ram would not be compatible with my old trim pump. Is that true? One of my rams is OK but the other is faulty. I have a 470 with a MR outdrive. Dave
 
Ayuh,..... You would need to replace both rams, 'n the lines outside the transom,.......
The early rams are 1" bore, the newer are 1, 1/4",....
 
Phantomsculler said:
Hi All. Can I replace a pre alpha trim ram (2 hydraulic input holes at the transom end) with an alpha 1 ram (1 hole at transom end and 1 hole underneath and facing down at the other end) ? I have read somewhere that the different ram would not be compatible with my old trim pump. Is that true? One of my rams is OK but the other is faulty. I have a 470 with a MR outdrive. Dave
Click to expand...
"Faulty", as in leaking? Could the seals be replaced?

Part number 87400A2
 
That would require using new larger bushings & a new down hose.
However, with the new diameter cylinder, the new ram will have more force & possibly cause the drive to want to come up crooked? Maybe?
Also, the new cylinder has 3 degrees more down travel & may put a twist into the equation at full down.
Bleeding procedure is different too.

As for your pump question, your drive should use the reverse lock valve in the system. The cylinders don't care either way. But old square pumps with aluminum reservoir need a reverse lock valve. Otherwise the drive will come up in reverse. Later pumps have check valves built in. So it's pumps that must match the valving installed.

Old style cylinders are everywhere, why not just buy one?
 
Droid said:
That would require using new larger bushings & a new down hose.
However, with the new diameter cylinder, the new ram will have more force & possibly cause the drive to want to come up crooked? Maybe?
Also, the new cylinder has 3 degrees more down travel & may put a twist into the equation at full down.
Bleeding procedure is different too.

As for your pump question, your drive should use the reverse lock valve in the system. The cylinders don't care either way. But old square pumps with aluminum reservoir need a reverse lock valve. Otherwise the drive will come up in reverse. Later pumps have check valves built in. So it's pumps that must match the valving installed.

Old style cylinders are everywhere, why not just buy one?
Click to expand...
Wouldn't buying only one cause the same kind of risk of twisting that you mentioned?
 
The way I read it, his boat is pre '82. So same cylinders from 1968 thru 82.
His question was could he just replace 1 cylinder using 1 from an R/MR/Alpha gen 1.

TBH, at 1st I read it as "could he put an early cylinder on a later boat?" Then I interpreted it the other way around.

Either way he will need to replace the bushings & down line on that cylinder. And yes a fatter cylinder has more force & more trim down range. So on retraction, the later cylinder will try to move 3 degrees further down. An early boat gimbal ring will not allow the additional travel range.

Early cylinders are simple to find used & unlike later cylinders, left & right are the same part number. And all 4 trim hoses are the same P/N too.

It just crossed my mind that I am not certain the fatter cylinder & down line will clear the gearcase fins.
 
A big thank you to all who replied. After considering all the comments and looking at the seals in the part # 87400A2 (thanks Jimn), I have come to the conclusion that my outdrive and rams cannot be MR. I now think that I have an even older MC-1 and it seems that if I tried to fit one of the rams with a hole at either end it would not work. I will have to chase up seals for the ram that I have and hope that my pump will continue to function. Thanks again guys. Even though these older parts will be a lot more scarce at least I have learnt a lot, and now know what I have to find. Have a great Christmas and holiday period. Dave.
 
I have rebuilt the trim rams on my OMC Cobra and the only tough part of the job is getting that end cap off. Once you’ve done that it’s not a hard job. My originals lasted 35 years before they leaked! Make sure seals are available and get a good quality pin wrench.
 
Phantomsculler said:
A big thank you to all who replied. After considering all the comments and looking at the seals in the part # 87400A2 (thanks Jimn), I have come to the conclusion that my outdrive and rams cannot be MR. I now think that I have an even older MC-1 and it seems that if I tried to fit one of the rams with a hole at either end it would not work. I will have to chase up seals for the ram that I have and hope that my pump will continue to function. Thanks again guys. Even though these older parts will be a lot more scarce at least I have learnt a lot, and now know what I have to find. Have a great Christmas and holiday period. Dave.
Click to expand...
According to the Mercury EZ Parts Web site, which isn't working at the moment, the years shown for MR are '83-'87. If you post the serial number for the drive, it's possible to be more accurate when looking for parts.

Look on Ebay, Craig's List and Facebook Marketplace for the cylinders if you need to replace but the seals shuld be available from other sellers.
 
Trim ram cap removal.jpg

This is a salt water used unit and so I knew the caps would not be easy to get off. I carefully heated the area around the cap with a heat gun to get the aluminum warm and put my full weight into holding the pins in place and to my surprise they both came off. I didn't think of it then, but if you're careful you might be able to use an impact gun here.
I bought some used fresh water cylinders because my old rods were pitted, (20+ years of salt water mooring). I left the old cylinders on the transom mount (this saved having to disturb the hydraulic line fittings) because the inside of the cylinders looked great. BRP/OMC sells a seal kit for these, so you can rebuild each one for like $50 or so. Once you get the caps off, it's an easy job.
Trim ram rebuild.jpg

All done. A little messy but all's well that ends well!
 
louc said:
This is a salt water used unit and so I knew the caps would not be easy to get off. I carefully heated the area around the cap with a heat gun to get the aluminum warm and put my full weight into holding the pins in place and to my surprise they both came off. I didn't think of it then, but if you're careful you might be able to use an impact gun here.
I bought some used fresh water cylinders because my old rods were pitted, (20+ years of salt water mooring). I left the old cylinders on the transom mount (this saved having to disturb the hydraulic line fittings) because the inside of the cylinders looked great. BRP/OMC sells a seal kit for these, so you can rebuild each one for like $50 or so. Once you get the caps off, it's an easy job.
View attachment 36591
All done. A little messy but all's well that ends well!
Click to expand...

I like that cover.
 
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