Need help with hydraulic cyl rebuild

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.
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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.
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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.
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Karl Townsend
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.
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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 bastards 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.
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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.
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Cheers or tears?
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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.
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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.
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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.
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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?
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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.
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