Rebuilding an Autopilot Hydraulic Ram or just Replace?

[motaman9]

We have a hydraulic autopilot ram that is 1.5" bore, 12" stroke and a 5/8 rod. We developed a leak at the working end of the cylinder. After removing it from the boat and taking it to a local shop back home we were told it had grooves and a rough spot on the rod which cut the nylon washer causing the leak. It was rebuilt in Spring of 2013 by prior owner at a shop in FL. The ram itself doesn't have any manufacturer emblems or marks on it. It is an aluminum casing and strongly resembles a Teleflex / Seastar. The rebuild shop wants $375 to re chrome the rod but a few other shops seem to think they can have a new rod made for less than that. It seems a whole new Teleflex / Seastar in a comparable size can be had for about $463?? Does anyone have any experience with rebuilding vs replacing either the whole unit or just the rod? Or maybe there's a scenario I haven't considered ??? Thanks

[mikereed100]

I would be surprised (would not be the first time) if the rod were not solid s/s. That being the case, I would be tempted to simply polish out the grooves and replace the seals. I'm interested to hear what the machinists here have to say.

[Nicholson58]

Originally Posted by motaman9

We have a hydraulic autopilot ram that is 1.5" bore, 12" stroke and a 5/8 rod. We developed a leak at the working end of the cylinder. After removing it from the boat and taking it to a local shop back home we were told it had grooves and a rough spot on the rod which cut the nylon washer causing the leak. It was rebuilt in Spring of 2013 by prior owner at a shop in FL. The ram itself doesn't have any manufacturer emblems or marks on it. It is an aluminum casing and strongly resembles a Teleflex / Seastar. The rebuild shop wants $375 to re chrome the rod but a few other shops seem to think they can have a new rod made for less than that. It seems a whole new Teleflex / Seastar in a comparable size can be had for about $463?? Does anyone have any experience with rebuilding vs replacing either the whole unit or just the rod? Or maybe there's a scenario I haven't considered ??? Thanks

I deal with a lot of hydraulic reps. You might get lucky if you contact the nearest Parker hydraulic rep and ask for a new replacement equivalent. These guys often make drop-in replacements and specialty cylinders for us. Some may be rebuildable - buy a seal kit too. Even cheaper alternate might be BIMBA or Clippard.

[motaman9]

Originally Posted by mikereed100

I would be surprised (would not be the first time) if the rod were not solid s/s. That being the case, I would be tempted to simply polish out the grooves and replace the seals. I'm interested to hear what the machinists here have to say.

The shop claims it is rolled steel, chromed and then threaded....the issues with removing the grooves is that if you grind it down or polish the grooves out you lose the diameter to fill the seal and it still leaks

[motaman9]

Originally Posted by Nicholson58

I deal with a lot of hydraulic reps. You might get lucky if you contact the nearest Parker hydraulic rep and ask for a new replacement equivalent. These guys often make drop-in replacements and specialty cylinders for us. Some may be rebuildable - buy a seal kit too. Even cheaper alternate might be BIMBA or Clippard.

It's technically "rebuild-able"....I can rechrome the original rod....or replace the rod....or replace the whole unit.....I was more worried about future dependability vs price to just replace the whole thing

[Acushla]

To ensure that you get the proper fit up following repair you should go with the re-chrome. However get your repairer to spell out his proposed repair process and sizing. The rod will require to be ground to remove all previous damage and enough for the substrate layer plus the hard chrome finish and final regrind to finish size. You want to know the final chrome thickness after final regrind. This followed by a new seal set and you are all set to go. The pricing quoted is not a bad price for the work required.
Cheers Acushla

[a64pilot]

Less than $100 difference? Buy a new one and put new wipers and O ring in the old one as a temporary spare if needed one day.
What's the warranty on yours if you have if fixed and it only lasts a month?


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[model 10]

You might be getting a little bit of a bum steer If the old shaft is just a piece of cold rolled with chrome plating and threads, it would not cost $400 to make. If it were a centerless ground shaft with hard chrome plating, then it could be worth $400. One reason to re-chrome a shaft is to bring it back to proper specs. They can re-grind the shaft and load up on the nickel layer and bring it back to specs. All of this would be a waste of $$ if it is just a piece of cold rolled steel with chrome plating.
I would look for somebody with a lathe and have them make one from stainless, for maybe $200.

[colemj]

Listen to a64pilot and learn the easy way the lesson we all have learned the bitterly hard way - if the cost of a repair is more than 50% of a new unit, get the new unit.

In your case, it really is a no-brainer.

Mark

[belizesailor]

Regardless of whether you rebuild/replace, learn how to rebuild and keep spares aboard, its easy and cheap just to repace seals/etc....on my todo list for tomorrow in fact.

[motaman9]

Originally Posted by belizesailor

Regardless of whether you rebuild/replace, learn how to rebuild and keep spares aboard, its easy and cheap just to repace seals/etc....on my todo list for tomorrow in fact.

I could rebuild it, but I'm not able/prepared to rechrome the rod.... So I'm kinda stuck on this one since they don't charge much more to reassemble/reseal it once the chroming is done.

[motaman9]

Originally Posted by a64pilot

Less than $100 difference? Buy a new one and put new wipers and O ring in the old one as a temporary spare if needed one day.
What's the warranty on yours if you have if fixed and it only lasts a month?


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Most warranties I've seen for shopwork are only 90 days....the rest is really part of my overall question, which is......does $463 seem like a "knock off" or refurbished unit price, in which case I'm no better off than rebuilding mine. That seemed low to me considering that some new units were $1400???.....Part of the overall issue is that my ram doesn't have any manufacturer markings on it.....so it's hard to compare.....it looks like an aluminum Teleflex / Seastar but it doesn't match dimension wise to any of their units

[motaman9]

Originally Posted by Acushla

To ensure that you get the proper fit up following repair you should go with the re-chrome. However get your repairer to spell out his proposed repair process and sizing. The rod will require to be ground to remove all previous damage and enough for the substrate layer plus the hard chrome finish and final regrind to finish size. You want to know the final chrome thickness after final regrind. This followed by a new seal set and you are all set to go. The pricing quoted is not a bad price for the work required.
Cheers Acushla

Is there a bad thickness for the chrome to be? Or is thicker better for the chrome? They are including the rebuild and re-chroming for the $375.....

[colemj]

I can't believe for the difference of $90 (20%) less than new you are still pursuing rebuilding this thing.

I guess one needs to learn those bitter hard lessons first hand…

Mark

[model 10]

Originally Posted by motaman9

Is there a bad thickness for the chrome to be? Or is thicker better for the chrome? They are including the rebuild and re-chroming for the $375.....

I don't think you grind the chrome. The chrome is the final surface on top of nickle on top of maybe copper on top of steel. The surface the o ring touches is not ground. The people who do this stuff know all about it, you don't need to worry how thick it is.