Doug,
thankyou for your long reply. Following your advive I posted the picture in
the following link:
http://community.webshots.com/photo/...99953239ZGLvQd

The backstay adjusters does not maintain the tension and leaks slightly
around the rod and around the small pump cylinder. What I need is a
complete set of new seals and, probably, new stainless steel balls that act
as valves. My problem is: I don't know the exact size and kind (compound,
shape, etc.) of the seals and the size of the balls and such information
could be obtained from the original manufacturer.
Just to anticipate a possible question: finding the size of the seals is
actually possible by just measuring the pistons and the bores; what is more
complicate is a guess on the kind of seals and the size of the ball-valves.
Unfortunately the device appears to have been already "overhauled" by
personnel who substituted parts that clearly do not fit.

Regards
Daniel
SPAM

"DSK" ha scritto nel messaggio
...
Valeria Dal Monte wrote:

I have this old hydraulic backstay tensioner (approx. 1980) but I have
no
idea of what it is. Apparently it is not one of the more common brands.
Do you have any suggestion?

It is a fairly simple machine with few moving parts, the job should be
easy
to get your backstay tensioner working again. Finding the correct parts
might
not be so simple.

The most common problem is leaking hydraulic fluid. It may need a shaft or
sleeve seal, which most likely is a rubber or soft plastic O-ring. The
control valve may be leaking, which would allow the tensioner to slowly
(or
not so slowly) lose it's tension without any apparent leaks on the outside
of
the cylinder.

If you get a big pan, you can take the tensioner apart without getting
hydraulic fluid all over everything. Then you can get a good idea what
parts
are needed. Often, hydraulic fluid gets a little water in it which
corrodes
interior parts. The valves & inside wall of the cylinder can be lapped &
polished; although it may be easier to replace the valves.

Your picture did not come through. Would you consider posting it at
www.webshots.com and posting a link to the picture here? We could give
better
advice after seeing it.

Fresh Breezes- Doug King