Volp
Silver Member
- Joined
- Jun 14, 2002
- Messages
- 110
- Tractor
- Massey Fergussom MF35, Kubota B6001, JD LX186 Lawn tractor. Ford Super Dexta 3000
With this posting I would like to share my experiences renovating a hydraulic cylinder and maybe learn a better way of doing it!
The problem started when my backhoe stopped swinging. I examined the swing cylinders and discovered that the piston rod no longer was connected to the piston! The reason for this could be that the cylinder support was loose due to a defective weld. I removed the cylinder expecting that a replacement was necessary but decided to first try to renovate it myself.
The first problem was to remove the piston. After unscrewing the cylinder end I managed to screw back the piston a few turns (the threads were damaged) and then attach a chain hoist to the rod end and draw out the piston. I don’t have the tools for rethreading so I used a “Dremel” type tool with a small cutoff wheel to clear up the threads. The rod could then be screwed back in the piston and secured with a new spring pin.
But first I replaced the old piston packing with a new.
Second problem: How to pass the rod through the cylinder end without damaging the new packing on the sharp edge before the threads at the end of the rod. The solution was “gaffa tape” (gaffa tape can mend everything except a broken heart or bad haircut) tightly wound and greased.
Replacing the piston seals was easy, just noting the positions of the old seals an replace them with the new.
Third problem: how to insert the piston in the cylinder without damaging the seals on the inside threads at the end of the cylinder. Thinking of a piston ring compressor I cut out a piece of brass plate 0.5-millimeter thick covering the threads then placed on the inside of the cylinder. With a rubber hammer I then drove the piston down into the cylinder. Screwed on the cylinder end after replacing the O-ring.
I tried to do most of this on a clean sheet to avoid contamination.
After reinforcing the cylinder mounts I mounted the cylinder and it worked!! Saved myself the cost of a new cylinder.
Any suggestions as to what I did wrong or could have done in an easier way?
The problem started when my backhoe stopped swinging. I examined the swing cylinders and discovered that the piston rod no longer was connected to the piston! The reason for this could be that the cylinder support was loose due to a defective weld. I removed the cylinder expecting that a replacement was necessary but decided to first try to renovate it myself.
The first problem was to remove the piston. After unscrewing the cylinder end I managed to screw back the piston a few turns (the threads were damaged) and then attach a chain hoist to the rod end and draw out the piston. I don’t have the tools for rethreading so I used a “Dremel” type tool with a small cutoff wheel to clear up the threads. The rod could then be screwed back in the piston and secured with a new spring pin.
But first I replaced the old piston packing with a new.
Second problem: How to pass the rod through the cylinder end without damaging the new packing on the sharp edge before the threads at the end of the rod. The solution was “gaffa tape” (gaffa tape can mend everything except a broken heart or bad haircut) tightly wound and greased.
Replacing the piston seals was easy, just noting the positions of the old seals an replace them with the new.
Third problem: how to insert the piston in the cylinder without damaging the seals on the inside threads at the end of the cylinder. Thinking of a piston ring compressor I cut out a piece of brass plate 0.5-millimeter thick covering the threads then placed on the inside of the cylinder. With a rubber hammer I then drove the piston down into the cylinder. Screwed on the cylinder end after replacing the O-ring.
I tried to do most of this on a clean sheet to avoid contamination.
After reinforcing the cylinder mounts I mounted the cylinder and it worked!! Saved myself the cost of a new cylinder.
Any suggestions as to what I did wrong or could have done in an easier way?