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Navtec hydraulic backstay adjuster leaking

kiwisailor

Member III
Blogs Author
This last weekend I was starting preparation for spring launch and I discovered the Navtec hydraulic backstay adjuster has been leaking and lost all of it's oil over the winter. A bit surprising as the adjuster was under no pressure.

It looks like the top seal has gone so I'm now looking at my options. Should I obtain a replacement seal kit for $120 and hope that solves the issue or should I just remove it all together go with a fixed backstay with traditional turnbuckle adjuster?

Cheers,
Mike
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Hydraulics... good and not-so-good

IMHO: Common problem with old integral back stay hydraulic adjusters.

Our '88 boat came with a Navtec unit. It leaked out fluid after a few years and I had it rebuilt. In a few more years it did it again.
Following the lead of another EY owner in our club I changed to a SailTec adjuster. It is working fine.
SailTec is a small company and nice to work with, also.

Another owner I know put a Wichard mechanical adjuster on his E-32. Less speed of change, of course, but much less complexity as well.

Plan B: You can always re-rig with a cascading purchase block-and-line system, but getting to the same pull will take a Lot of purchase. We sail at about 1K and pump it up to about 1800 for heavier air to windward.

Sidebar: when we re-rigged with all new standing rigging, our rigger advised us to add a turn buckle right above the hydraulic unit. That way we can take the BS up tight for everyday sailing if the hydraulic one fails while we are on vacation. Sort of a "belt and suspenders" approach. When you do that you size the BS length so that you can barely make the pin connections when the turn buckle is at full extension.

Regards,
Loren
 

JPT

Junior Member
I used Jay Maloney at Maloney Marine Rigging (http://maloneymarinerigging.com) a year ago and he did a great job of overhauling my Navtec backstay adjuster with a new seal kit and rod as well. He's in Southport, ME, and so is closer to you than San Diego, but you may find someone closer yet to Groton.

Regards,

Jon
 

kiwisailor

Member III
Blogs Author
What's it worth to repiar ....$500

I used Jay Maloney at Maloney Marine Rigging (http://maloneymarinerigging.com) a year ago and he did a great job of overhauling my Navtec backstay adjuster with a new seal kit and rod as well. He's in Southport, ME, and so is closer to you than San Diego, but you may find someone closer yet to Groton.

Regards,

Jon

Hi Jon,

I got an estimate of ~$500 from Sound Rigging in Essex, CT. I was planning have backstay insulators fitted at a later date for the SSB radio and may bring that project forward and remove the adjuster at the same time. Not that keen on spending $500 repairing the adjuster if I only get a couple of years out of it.

Cheers,
Mike
 

Slick470

Member III
Another place you might check on a price is Oyster Bay Boat Shop. I haven't checked in with them in a few years but last I spoke to them they did Navtec integral backstay rebuilds.

Best contact for them is Bam Miller at bam@oysterbayboatshop.com
 

CTOlsen

Member III
Try a local shop

I had my back stay adjuster rebuild by a local hydraulics shop when I kept the boat in the southern Chesapeake bay. I gave them the manual for my particular unit, but they didn't need it. They rebuild it with new seals, made a new shaft since they found a "booger" on the old one, and returned it in 2 weeks. Total: $250.00.
Hydraulics are hydraulics whether they come off of farm equipment or sailboats. Mine has lasted 5 years with no problems.
 

tiredold

New Member
Navtec "secrets" revealed

My backstay started leaking by the rod seal. I dismantled the unit as far as I could and like everyone else, could not figure out how to separate the square tube body from the pump base without risking damage to the tube. Fortunately after an extensive web search I found document that list a breakdown and parts listing for most of Navtec's products:

https://www.hisse-et-oh.com/system/...avtec_hydraulik_service_manual.pdf?1321964899

After removing the rod with the piston, there is a gland nut at the bottom of the tube that screws it into the base. The nut has a slot groove in it. I could not find a screw drive ANYWHERE that was wide enough. It must be 1 1/8 wide as there is a centre hole in the nut. (the top four screws in the cap only hold the cap on, also be careful removing the screw, ONE of the also covers a plug in the bottom of the screw hole that is part of the hydraulic circuit). Fortunately I have a machine shop and was able to manufacture the required driver out of a piece of 1 1/8 round bar that I milled one end into a flathead screwdriver point. I then covered the rod with tape so that it would not score the inner rod barrel. Total length is about 2 feet so that it can reach to the bottom of the tube. I just slid it in and the nut turned right out. I can gladly send pictures of it, or even SEND it to anyone that needs it (at no charge) by taking it to a UPS store, and you do the rest. Just send it to the next person that needs it and no charge.
I got the complete seal kit from
https://store.offshorespars.com/products/navtec-10-series-7-integral-backstay-adjuster-seal-kit

Al I can say is EXCELLENT. Just be ultra careful with the two little springs. Drop or mishandle them and they will bounce into orbit. I think one of mine is still orbiting the space station.

It gets really tricky with the valves. Just do them ONE at a time. And be careful making sure that you do not mix up the balls. Plus be ultra careful with the high pressure relief valve. Make sure the ball is seated perfectly before you reinstall the spring. It may hang up if not seated in the exact spot. Put the ball in and use a small hex key to make sure that it is seated before replacing the spring. I eventually put the ball on the end of the spring holding it with the ball sitting on top of the spring and sliding it up in the valve body with valve body above it. This little step took me a month to figure out. When the pump was reassembled it would not build pressure, I could see oil moving back and forth out of the reservoir, a clear indication that a valve was not seating. This unit is extraordinarily designed with some of the hydraulic passages serving two purposes. I found this after hours of putting probes through the passages in order to figure out the hydraulic schematic. Like the nut at the bottom of the tube barrel, once you see it, it is clear, but a mystery until you do see it. I my case there was a score mark on the valve seat that I could only see with help of high magnification from my smartphone (a really helpful tool). Once I lightly used a drill (using my fingers, not a drill) to remove the burr, it built pressure on the first pump.
For the piston seal, I see this is also a source of trouble for people. I found two large sockets, putting one at a time on against the seal and putting the whole thing in a smooth jaw vise (I just put several layers of shop rage over the jaws) I just carefully closed the vise pushing the seal up into the groove in the piston. One socket will only push the seal part way until it runs into the taper of the piston, then just switch over to the next larger socket to push it the rest of the way. Also do not put in the Teflon bushing into the same grove until the piston seal is in the grove. And even then only after you put the piston onto the rod and reinsert the pin that holds the piston to the rod.
Just play out each couple of steps ahead of time in your head so you do not have to redo anything.
The unit is brilliantly designed and not all of its features are initially apparent, and it is huge EXPENSIVE, but well worth the effort. As a side note, mine has been installed for about four months and not a single drop of oil or drop in pressure.
P.S. DO NOT USE red transmission fluid. It will appear to work BUT WILL eventually destroy all the rubber seals. Use 30 W non detergent (I used hydraulic jack oil).
I know this is a long winded reply, but I just wanted to help anyone that is in the same position.
If you have questions or want to borrow the tube nut tool, or just want pictures of it, just ask. jsocket@interlog.com
 

Gary Filgate

Junior Member
Hello,
I just came across your post on the Ericson owners forum on rebuilding the Navtec Series 7-10 back stay tensioner. Your post was excellent - Thanks! I am a part time machinist and am interested in the pictures you have of the nut remover you fabricated, and any other helpful advise you have. I was an Engineer in the Coast Guard and worked at Portsmouth Naval Shipyard, so have a lot of experience with hydraulic systems. I know some jobs that appear to be straight forward and look easy can be a nightmare when you get into it!
I look forward to the pictures and any tips you might have.
Best Regards,
Gary Filgate
E 35-3 Dragonfly
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Gary, he has not logged in for a while. Best to click on his name and message him directly.
 
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