oceanobob
Senior Member
Couple questions about replacing the piston rod, but first a background explanation....thanks.
The rods accumulate nicks and dings, rust pits, scratches, etc. and when the cylinder-to-rod seal leaks, the local hydraulic repair shop (or dealer repair shop) suggests us to replace the rod. Although the OEM can provide a replacement rod complete with rod eye (and this can often entail a new bushing line item as well), the hydraulic shop or the OEM repair shop will sometimes coordinate the rod replacement with a local 'machine shop' and they procure chromed bar(s).
The repair procedure involves cutting off the old eye, re-welding it to the new rod, threading the end for the piston and then the hydraulic shop puts it back into the cylinder and away one goes. Oh, $$$ don't forget.
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The machine shop won't / don't / can't provide any details about:
- the rod material, chrome thickness and type, etc [Rod Quality]
- the welding process for the eye to the rod
Since I have to provide all these details and more as a "Contractor", I can't in good conscience assign them the work since they are, let's say, lackluster in this regard. And the Prince cylinders' rods we got from Northern for our ramps for the equipment trailer definitely don't have the same chrome as say the OEM rods on the hoe or dozer. I have thought about buying the rod and then having them thread it and weld it myself, pls read on.
As to simply going to a better shop suggestion: Yes, the Quinn Caterpillar hydraulic repair shop can do all the above with Cat parts and in exact accordance procedures so, yes we can find a shop we can trust - but am thinking our shop with a lathe and welders should be able to accomplish these projects, and with the economy....and the shop rent is the same if we use it or not....
**
My Questions:
In general The Rod looks like it is centerless ground 1045 steel bar ....which in these sizes will likely have a pretty high hardness throughout. Meaning: don't think it will turn & lathe like a high school shop class assignment.
We can also order it in an induction hardened version which should increase the life due to the improved surface hardness.
There are optional proprietary processes to apply the chrome to assure absolute consistent diameters.
Chrome thicknesses range from half a thou to one thou or two thou (.0005", .001", .002"), this is the case it seems in whatever steel rod is the base selection.
Questions:
Any suggestions on induction hardened or standard?
Any suggestions on chrome thickness?
AND
Any advice on the machining? Especially if we have to internally thread a bolt hole on the piston end? Carbide drills and tap is what I am thinking we need to come by from the tooling supplier although if we need to make a shoulder and an external thread then the lathe will accomplish this, albeit with some carbide cutting tools.
As to the Welding: am figuring on grinding off the chrome in the weld area and then prep for partial pen, some preheat and 7018, then cool slowly perhaps in some lime.
As to this subject of solving these damaged hydraulic rod problems, I checked on the forum and there was a lot of advice about not using various topical applications to fix pits/nick/dings/scratches since these can go into the system not if but when they detach.
I wanted to include all the points that we have investigated and hope this helps out others who have similar concerns about dings and pits reducing seal repair life.
FYI These are the rods that I have in mind for fixin:
- 580K stabilizers
- 580K bucket
- 450G blade lower raise
- reachlift chassis to axle (sway)
The rods accumulate nicks and dings, rust pits, scratches, etc. and when the cylinder-to-rod seal leaks, the local hydraulic repair shop (or dealer repair shop) suggests us to replace the rod. Although the OEM can provide a replacement rod complete with rod eye (and this can often entail a new bushing line item as well), the hydraulic shop or the OEM repair shop will sometimes coordinate the rod replacement with a local 'machine shop' and they procure chromed bar(s).
The repair procedure involves cutting off the old eye, re-welding it to the new rod, threading the end for the piston and then the hydraulic shop puts it back into the cylinder and away one goes. Oh, $$$ don't forget.
*
The machine shop won't / don't / can't provide any details about:
- the rod material, chrome thickness and type, etc [Rod Quality]
- the welding process for the eye to the rod
Since I have to provide all these details and more as a "Contractor", I can't in good conscience assign them the work since they are, let's say, lackluster in this regard. And the Prince cylinders' rods we got from Northern for our ramps for the equipment trailer definitely don't have the same chrome as say the OEM rods on the hoe or dozer. I have thought about buying the rod and then having them thread it and weld it myself, pls read on.
As to simply going to a better shop suggestion: Yes, the Quinn Caterpillar hydraulic repair shop can do all the above with Cat parts and in exact accordance procedures so, yes we can find a shop we can trust - but am thinking our shop with a lathe and welders should be able to accomplish these projects, and with the economy....and the shop rent is the same if we use it or not....
**
My Questions:
In general The Rod looks like it is centerless ground 1045 steel bar ....which in these sizes will likely have a pretty high hardness throughout. Meaning: don't think it will turn & lathe like a high school shop class assignment.
We can also order it in an induction hardened version which should increase the life due to the improved surface hardness.
There are optional proprietary processes to apply the chrome to assure absolute consistent diameters.
Chrome thicknesses range from half a thou to one thou or two thou (.0005", .001", .002"), this is the case it seems in whatever steel rod is the base selection.
Questions:
Any suggestions on induction hardened or standard?
Any suggestions on chrome thickness?
AND
Any advice on the machining? Especially if we have to internally thread a bolt hole on the piston end? Carbide drills and tap is what I am thinking we need to come by from the tooling supplier although if we need to make a shoulder and an external thread then the lathe will accomplish this, albeit with some carbide cutting tools.
As to the Welding: am figuring on grinding off the chrome in the weld area and then prep for partial pen, some preheat and 7018, then cool slowly perhaps in some lime.
As to this subject of solving these damaged hydraulic rod problems, I checked on the forum and there was a lot of advice about not using various topical applications to fix pits/nick/dings/scratches since these can go into the system not if but when they detach.
I wanted to include all the points that we have investigated and hope this helps out others who have similar concerns about dings and pits reducing seal repair life.
FYI These are the rods that I have in mind for fixin:
- 580K stabilizers
- 580K bucket
- 450G blade lower raise
- reachlift chassis to axle (sway)