Hi, Redeye. To straighten a hydraulic cylinder rod, you will need:
1. A reasonably good hydraulic press - the bigger the rod diameter, the more grunt the press will need.
2. Several blocks of hardwood - somewhere around 2x3 or 2x4 is usually good but you will need thicker pieces if you have a piston diameter that leaves 2 inches or more of the piston clear around the rod. Also, a piece of 1/2 inch or thicker steel plate to put on top of the short hardwood block that you are going to place ON TOP of the rod between it and the press ram.
3. A good engineers straight edge or other straight edged piece of steel or aluminium - aluminium is good for obvious reasons.
4. A warm sunny day. Leave the bent rod in the sun for several hours to warm up. When it no longer feels cool to touch it will be ready, but if you can leave it until it feels slightly warm to touch it is even better. Place the rod in the press on the hardwood blocks so that NO part of the rod, piston or eye is touching any part of the bed of the press. Apply pressure at the centre of the bend with another short hardwood block laid along the rod and the piece of steel plate on top of that between rod and press ram head. Do not attempt to take all the bend out in one go. This is what breaks rods. Take a little at a time and move the rod slightly back and forth through the press between pushes so that you are pressing in a slightly different place each time. Around an inch either way is usually sufficient. This will help not only to eliminate rod breakages but also stop two smaller opposite bends appearing, one each side of the centre of your original bend. Use your straight edge to check when you are getting close. You may have bent the rod quite quickly but that is no reason to rush the straightening of it. Slow and steady is definitely the best formula here. I have had many major engineering shops refuse to touch bent rods. The man who showed me was an 'almost backyarder', a middle-aged Danish immigrant to Australia, who was rushed off his feet with work. Musta bin sumpin goin' on there. Happy rod straightening. you have a wonderful day. Best wishes. Deas Plant.
| 
