Jump to content

Recommended Posts

I pumped the backstay on my '83 J35 and was greeted by red hydraulic fluid oozing from the top of the piston mounted to the rod backstay. Just wondering if anyone has a schematic of the piston so I can figure out how to replace seal. Thanks in advance.

Link to post
Share on other sites

No one can tell what brand of adjuster you have - there are at least 3 main possibilities. And it is a finicky job, so unless you're experienced in marine hydraulics, send it to a qualified repair shop.

  • Like 1
Link to post
Share on other sites

I appreciate the input. My thought is that all components are installed for hydraulic backstay, including pump, reservoir, tubing, rod backstay and the aforementioned piston. To change to line purchase system would entail disconnect at top of mast and reattach with line. Measuring line and installation of attachment points at transom and installing blocks. Let me see how difficult it is to remove piston. Thanks again for your suggestion. Maybe a winter project. 

Link to post
Share on other sites

Its probably a Navtec cylinder. I suppose its doable. taking it apart is easy, putting it back together is not as easy. there are special tools needed to get it all back together. I'd think Longy's got the right advice.

Fluid shouldn't be red, and if its leaking out the top the issue is with gland seals under the top cap.

Link to post
Share on other sites

Many cylinders are gas pressurized. Dangerous to disassemble if not fully de-pressurized. 
 

Readily serviced by riggers. 
 

I don’t get why the cylinders on my tractor last decades in horrendous conditions while the boat cylinders do not. 

Link to post
Share on other sites

Farm/construction equipment have large fluid reservoirs. Just pour more hyd oil in as it leaks out in various places. The leaks are viewed as a bonus- help prevent rust. And drips fall on ground, not on shiny boat bits.

Link to post
Share on other sites

It is a bit of a project.  I just disconnected the cylinder at the stern and left everything else in place incase I decide to go back with a new cylinder.  Took down the Rod Backstay. 
 

Made a Backstay of 7mm Spectra Core with heat shrink. Then did the Cascade Purchase. Took three days, not counting down time to live. 

Link to post
Share on other sites

An individual from the J35 Class Association advised how to decompress the piston, remove it and told me where to get the repair kit. When I eventually get back out I'll give it a go and let you know how it went. I don't have the individual's permission to use his name, but seems to be incredibly knowledgeable. 

  • Like 2
Link to post
Share on other sites
  • 2 months later...

Postmortem on the hydraulic backstay piston. The best advise was not to attempt to do this myself. A mechanic I know and trust referred me to a guy he uses for hydraulic work. He had the piston for a couple of weeks and wound up sourcing it out to someone he knew. Piston finally came back and it works and doesn't leak. It is a navtec and they seem to still be in business in Connecticut.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...