I recently inherited an old Raymond fork truck and the hydraulic
cylinder that does the lifting is leaking badly. The ram appears in
good shape, I can see no gouges or grooves and it doesn't seem to be
bent, but the oil seal at the top is clearly leaking and I assume that
the piston seal is also shot. I bought a seal kit from a Raymond
parts dealer, but I'm not sure how best to go about the rebuild.

My first thought was to remove the entire cylinder from the truck and
do the work at the bench, however the high pressure feed line at the
bottom is difficult to access and I can't figure out a way to
disconnect it.

My second idea was to leave the cylinder in place and extract the ram
vertically. I can remove the retaining ring from the top end of the
cylinder easily enough, but the seal below it will be tougher to
extract. Is pumping the ram up to the top and out of the cylinder
with hydraulic pressure a dumb idea? The ram is long an heavy and
will be tough to support, but I might be able to rig a cable to hang
it from the shop ceiling.

Any ideas or advice will be greatly appreciated! Thanks.

On 23 Mar, 19:27, Loki9 wrote:
I recently inherited an old Raymond fork truck and the hydraulic
cylinder that does the lifting is leaking badly. *The ram appears in
good shape, I can see no gouges or grooves and it doesn't seem to be
bent, but the oil seal at the top is clearly leaking and I assume that
the piston seal is also shot. *

These cylinders are usually single acting and only have a rod seal at
the top and no piston.Does your kit have a piston seal kit or just
chevrons?
If it is single acting it is normally possible to change the rod seal
without removing the cylinder.

Just a suggestion. Run lift all the way up. screw and bolt in several 2x4s
to hold lift mast all the way up. Make a cylinder rod clamp by bolting two
piece of metal together and drilling out bore. Use a come along to pull
cylinder the rest of the way out after disconnecting from mast. The mast
should provide a spot for your come along.

Karl

On Mar 23, 4:52*pm, mark wrote:

These cylinders are usually single acting and only have a rod seal at
the top and no piston.Does your kit have a piston seal kit or just
chevrons?
If it is single acting it is normally possible to change the rod seal
without removing the cylinder.

Thanks for the help.

OK, hydraulics are not my thing, so I may have my terms crossed. I'm
not sure what chevrons are in this context. It is a single acting
cylinder, there is only one fluid connection at the bottom end of the
cylinder. The seal kit contains two annular rubber seals. One seal
includes a metal ring to bear against the snap ring at the top of the
cylinder. The other seal doesn't have the metal part, and I assumed
that one went on the bottom end of the rod. Are you saying that maybe
there is no seal on the end of the rod? Maybe the second seal is used
to close the bottom end of the cylinder? I can't see the bottom end
easily and I assumed that it is welded closed and therefore didn't
need a seal. The seal kit also included two identical snap rings.
One obviously closes the top of the cylinder, I wasn't sure if/where
the second one was used. I can probably replace the seal at the top
of the cylinder without removing the rod, but I don't know what to do
with the other one.

On Tue, 23 Mar 2010 20:29:28 -0700, Loki9 wrote:

On Mar 23, 4:52*pm, mark wrote:

These cylinders are usually single acting and only have a rod seal at
the top and no piston.Does your kit have a piston seal kit or just
chevrons?
If it is single acting it is normally possible to change the rod seal
without removing the cylinder.

Thanks for the help.

OK, hydraulics are not my thing, so I may have my terms crossed. I'm
not sure what chevrons are in this context. It is a single acting
cylinder, there is only one fluid connection at the bottom end of the
cylinder. The seal kit contains two annular rubber seals. One seal
includes a metal ring to bear against the snap ring at the top of the
cylinder. The other seal doesn't have the metal part, and I assumed
that one went on the bottom end of the rod. Are you saying that maybe
there is no seal on the end of the rod? Maybe the second seal is used
to close the bottom end of the cylinder? I can't see the bottom end
easily and I assumed that it is welded closed and therefore didn't need
a seal. The seal kit also included two identical snap rings. One
obviously closes the top of the cylinder, I wasn't sure if/where the
second one was used. I can probably replace the seal at the top of the
cylinder without removing the rod, but I don't know what to do with the
other one.


Yes, that is what he is saying. If it is a displacement cylinder it will
be this way.

Raymond made many different styles of trucks over the years and without
knowing or seeing what you see it is impossible to explain which style
lift cylinder you have. If you don't have a return line at the top of the
cylinder it is a displacement cylinder. As the oil enters the bottom there
is a fiber bearing sleeve on the piston that has oil trapped above the
piston. There is a check valve in the bottom of the lift rod that lets the
oil above the piston threw to the bottom of the piston as the rod is
displaced and rises. These are on many later model trucks. This can be
repacked by only removing the load that is carried by the cylinder such as
the lift chains and blocking up the carriage. Then removing just the
cylinder head to install the packing kit. The bearing sleeve on the piston
is probibly OK.

If there is a return line at or near the top then it is a single acting
cylinder that returns oil that seeps and is trapped above the piston
packing to the sump threw the return line near the top of the cylinder.
Common on older trucks. This requires the top gland nut and lift rod to be
removed normally to repack the whole cylinder.

Raymond made all electric trucks. Many were special to certain industries
and Raymond was the only manufacturer for some of these configurations.
This specialisation is what made Raymond more a dealer repair truck. They
also had their own electric drive system that changed much and often threw
the years. Some were *******s to work on because of quick changes in the
electric drive system that was unique only to Raymond. They sold some of
their electronic drive systems to Cat but the parts for each were unique
enough that most parts were not interchangeable.

The hydraulics were not so special. Most manufacturers followed and
accepted the norm over the years. But without knowing the model and serial
number it is a crap shoot. It has been too long and my memory grows
shorter of all the configurations. A blessing.

I know you needed the truck model a serial number to get a part. Probably
a deck (upright) number to get the correct packing.

Pictures would help! Do you have the parts book for "this" unit? A
breakdown of the cylinders is in the parts manual. A scan of the page for
this cylinder posted somewhere would help.

Here is a little more information.
http://www.dfma.com/news/raymond.htm

This shows some configurations but not all. Raymond also bought the rights
to a wire guidance system from an outfit in California, I want to say
about the early seventies that allowed the truck to be steered to a
location in a warehouse using a radio signal from a wire embedded in the
floor to retrieve products for shipment. The operator only controlled the
speed to the location and hands to grab the product.

Some Raymond's had more "widgets" than any other manufacturer. Good luck
getting parts as this grows older.

http://images.google.com/images?hl=e...f&oq=&gs_rfai=

Cheers or tears?

HTH!

Thanks Bubba, that was very helpful. Any tips on how to get the top
end seal out? I might be able to push it out with hydraulic pressure,
though that could get messy. Alternately, I might be able to pull it
out by grabbing the metal part of the seal with some type of puller.

On Thu, 25 Mar 2010 07:33:43 -0700, Loki9 wrote:

Thanks Bubba, that was very helpful. Any tips on how to get the top end
seal out? I might be able to push it out with hydraulic pressure,
though that could get messy. Alternately, I might be able to pull it
out by grabbing the metal part of the seal with some type of puller.

The "end seal" you refer to sounds like a "wiper" meant to keep out dirt
as the cylinder retracts. Once you have the cylinder head unscrewed and
off you can pry the wiper out. Use care not to distort the new wiper if it
has a metal form around the plastic wiper material. This only keeps the
rod wiped clean as it retracts or lowers in this case. The metal ring that
holds the wiper in place is easily bent if care is not used to install.

http://morsemfgco.com/ops/PL780.1.pdf

On page 1 of this pdf document, item 1 is the wiper. Item 3 show vee
packing A.K.A. Chevron or stacked packing. I suspect you may find a soft
plastic cup style packing in this position. This is what causes the leak.
With a blunt tool you should carefully be able to remove this and
reinstall the new packing. At the bottom of the cylinder head there may
also be a o-ring (Not shown in this diagram) inside or outside the
circumference of the head that will be in your reseal kit. Replace with
new, all parts that are contained in your seal kit.

Some progress. I managed to remove the wiper and the seal underneath
it. However, I'm a little confused as the new seal doesn't look
exactly like the old seal. The old seal is shaped like and inverted
U. It sits on top of a brass ring that has a tongue that can fit up
into the U. The new seal is identical, except that there is an O-ring
in the U. If I remove the O-ring then it looks just like the old
one. I can certainly do that, but I wonder about it. Maybe the O-
ring is just to keep the seal in shape while it sits on the shelf?

On Tue, 30 Mar 2010 09:55:13 -0700, Loki9 wrote:

Some progress. I managed to remove the wiper and the seal underneath
it. However, I'm a little confused as the new seal doesn't look
exactly like the old seal. The old seal is shaped like and inverted
U. It sits on top of a brass ring that has a tongue that can fit up
into the U. The new seal is identical, except that there is an O-ring
in the U. If I remove the O-ring then it looks just like the old
one. I can certainly do that, but I wonder about it. Maybe the O-
ring is just to keep the seal in shape while it sits on the shelf?

The o-ring (your words) is an improvement on the cup packing and should
help it last longer. Leave the rubber in the cup and use grease on all
packing. The top of the rod may need tapering with a fine tooth file
slightly to help get the new packing to slide over the rod. The rod
may be slightly mushrooned from years of vibration of the load of the
chain-head and carriage that the forks hang on . Inspect for burrs on top
of the lift rod before reinstalling the gland nut with the new packing
installed. Vasoline works fine here. Use care and a dull tool to install
the new cup in the groove to prevent nicking the cup. When pushing the
head over the rod end, you may use the dull tool to rub around the lip of
the new packing to work it over the rod. If there was a hard fiber ring
in the packing kit, this is a bearing for the piston at the bottom of the
rod. If you want to replace this, pull the rod clear of the tube and
install the new bearing. If you find a small 3/4" or so o-ring. This seals
the check valve in the bottom of the piston. Be sure to note which
direction the check valve is in when you remove it so as to get it in the
right direction when you reassemble it. The norm is a snap ring and washer
capture the check valve in the bottom end of the rod. Oil above the piston
is driven below the piston threw the check valve as fluid raises the rod.
All sealing of any leaks are taken care of at the top of the cylinder.

Is this the way you understand this to work?

Hope this helps.