Trim Ram End Cap Replacement

[Jmunk]

My Alpha 1 Gen 2 seems to be having a hard time trimming all the way down. The pump runs but the outdrive needs a push now and then. I believe that the trim rams end caps are likely due for replacement. I’d rather not try to remove the rams as the hose fittings may be hard to get off.

Can I pull the rear pin on the rams and then loosen the end caps and take the piston assembly to a bench vise and leave the ram housing still attached to the outdrive by the front pin?

Looks like I need part # 8M0118340, does this come with the end cap seals and everything I need?

 

[Bt Doctur]

The end cap need to be removed to service the rams O rings
As long as you can unscrew the end cap .Yes. take that assembly to the vise
When you remove the bolt to remove the check valves, DO NOT OPEN IT ,THERE ARE BALLS AND SPRINGS HELD CAPTIVE.
Failure to reassemble correctly will result in no cylinder operation

 

[achris]

Can I pull the rear pin on the rams and then loosen the end caps and take the piston assembly to a bench vise and leave the ram housing still attached to the outdrive by the front pin?

That's exactly how I do all the ones I service. Much easier to use the front pin as a hard support when attempting to remove the end cap (for which I have built my own special tool, made of 13mm thick steel bar and high tensile screws ).

Chris......

 

[Jmunk]

The end cap need to be removed to service the rams O rings
As long as you can unscrew the end cap .Yes. take that assembly to the vise
When you remove the bolt to remove the check valves, DO NOT OPEN IT ,THERE ARE BALLS AND SPRINGS HELD CAPTIVE.
Failure to reassemble correctly will result in no cylinder operation

Thanks for the heads up on the check valves. Hopefully the end cap isn’t seized into the housing.

That's exactly how I do all the ones I service. Much easier to use the front pin as a hard support when attempting to remove the end cap (for which I have built my own special tool, made of 13mm thick steel bar and high tensile screws ).

Chris......

I’ll have to take some measurements and see what I have laying around to cobble together into a tool. Do you come across many caps that are seized and require the ram to be fully removed?

With the drive in the full-up position and supported is there much pressure on the end cap when unthreading?

 

[achris]

I’ll have to take some measurements and see what I have laying around to cobble together into a tool. Do you come across many caps that are seized and require the ram to be fully removed?

If you can't remove it while the ram is on the boat, you are definitely not going to remove it when off.

With the drive in the full-up position and supported is there much pressure on the end cap when unthreading?

I leave the drive down, pull the rear pin, then hit the UP button (I have a transom mounted trim switch) until the rams are fully extended (Just tap the DOWN side to relieve the pressure). Then I tie the end of the ram to the back of the boat so it's pointing up (so the fluid doesn't fall on the floor) and loosen and remove the end cap. You can then pull the rod and piston out with very little fluid above the piston. You'll see the 'memory piston' still in the ram, ignore that and take the rod and main piston over to the bench, secure the end of the rod (the clevis) in the vice with it pointing up. You can then use a 9/16" ring spanner to loosen the bolt holding the piston to the end of the ram. Pull the bolt and piston off together (making sure the piston stays all together) and lay it carefully aside. Drive the end cap off the rod and then carefully fit the new end cap.

As the end of the rod is quite 'squared off' there is a risk of damage to the internal o-rings and the grounding wiper inside the end cap as you try to push it onto the rod. The next one I do I'll be taking some measurements and spinning up a nylon 'cap fitting tool'. This will allow the o-rings and wiper to slide on without hitting that hard edge, thus removing any risk of damage to them...

Chris.....

The plan for the tool, to be made out of nylon or delrin.. (If you can verify the thread on the bolt is 3/8" x 16 (UNC), that would be great, thanks.)

 

[Jmunk]

The plan for the tool, to be made out of nylon or delrin.. (If you can verify the thread on the bolt is 3/8" x 16 (UNC), that would be great, thanks.)

View attachment 364006

Thanks for the information as always. I will verify the bolt size in a few days once the new cap arrives and I replace the old.

What’s the likely hood that the starboard will fail like the port in the near future? Should I just do both at once?

I did try to loosen the end cap, to my surprised it loosened without too much of a fight.

I did see that the SEI end caps are half the price of the OEM. I’ve never tried anything SEI so not sure the savings is worth the time?

 

[achris]

My experience is that is such a quick and easy job that you don't need to do both at the same time. And it's unusual for both to go bad at the same time anyway...

Chris...

 

[Jmunk]

If you can't remove it while the ram is on the boat, you are definitely not going to remove it when off.

I leave the drive down, pull the rear pin, then hit the UP button (I have a transom mounted trim switch) until the rams are fully extended (Just tap the DOWN side to relieve the pressure). Then I tie the end of the ram to the back of the boat so it's pointing up (so the fluid doesn't fall on the floor) and loosen and remove the end cap. You can then pull the rod and piston out with very little fluid above the piston. You'll see the 'memory piston' still in the ram, ignore that and take the rod and main piston over to the bench, secure the end of the rod (the clevis) in the vice with it pointing up. You can then use a 9/16" ring spanner to loosen the bolt holding the piston to the end of the ram. Pull the bolt and piston off together (making sure the piston stays all together) and lay it carefully aside. Drive the end cap off the rod and then carefully fit the new end cap.

As the end of the rod is quite 'squared off' there is a risk of damage to the internal o-rings and the grounding wiper inside the end cap as you try to push it onto the rod. The next one I do I'll be taking some measurements and spinning up a nylon 'cap fitting tool'. This will allow the o-rings and wiper to slide on without hitting that hard edge, thus removing any risk of damage to them...

Chris.....

The plan for the tool, to be made out of nylon or delrin.. (If you can verify the thread on the bolt is 3/8" x 16 (UNC), that would be great, thanks.)

View attachment 364006

I changed the end cap out this evening. The old one didn’t want to come off the shaft without some work.

I checked and the threads are 3/8-16.

 

[achris]

I changed the end cap out this evening. The old one didn’t want to come off the shaft without some work.

Yep, corroded in the inner surface, right?

I checked and the threads are 3/8-16.

Thanks.

 

[Jmunk]

The corrosion seemed minor but I guess it doesn’t take much.

With the trim cylinders disconnected from the outdrive the cylinder with the bad end cap wouldn’t move until the other cylinder was fully in or out. When it did move it wasn’t smooth.

 

[achris]

With the trim cylinders disconnected from the outdrive the cylinder with the bad end cap wouldn’t move until the other cylinder was fully in or out. When it did move it wasn’t smooth.

That's normal. As the cylinders are connected in parallel, the cylinder with the least resistance will move first.

Chris...

 

[Searay205]

the end caps usually go bad when the boat is used in salt water. The salt collects behind the end cap seal and o-ring. the salt eventually causes the outer seal to expand and swell causing excessive friction on the trim cylinder rod. usually squeaking is heard. That being said when I overhauled the end cap (I am a cheap ass) I found excessive corrosion on the end cap. I had to get boat back to storage so I just filled corrosion area with extreme grease and reassembled to get back to storage. Figured I would replace with new one over winter. That was 5 years ago and still working perfect lol. One thing I almost blew my head off when I used my air compressor to get the piston out, trust me do at your own risk.

 

[achris]

... One thing I almost blew my head off when I used my air compressor to get the piston out, trust me do at your own risk.

Not good. Quickly running the numbers, that piston had around 600lbs of force behind it as it exited the cylinder... If it had hit you in the head, it would probably have been the last thing you ever did.

Chris...

 

[Grub54891]

Always wrap a towel over the end of whatever you are pushing out with air. Whether it be a ram, brake puck or valve of sorts.