Broken Bolt in Hydraulic Cylinder

[AmericanLandMgt]

While reinstalling the boom cylinder on my excavater I managed to shear one of the bolts that holds the metal hose bracket to the cylinder. I went and got my easy out set and proceeded to break that off as well. I removed the easy out but in the process buggered up the bolt hole to the point where it will not be possible to oversize drill it and put in a helicoil or tap new threads. I want to weld up the hole and then drill and tap a new hole but I am wondering if the heat from the weld will ruin the seals? If I mig weld it in little bursts and let it cool in between will it cause me any problems or do I need to pull the entire thing apart? I realy don't want to have to pay to have the thing taken apart but I don't want to ruin the freshly rebuilt seals either.

 

[lumberjack]

A picture sure would help.

 

[pointrow]

While reinstalling the boom cylinder on my excavater I managed to shear one of the bolts that holds the metal hose bracket to the cylinder. I went and got my easy out set and proceeded to break that off as well. I removed the easy out but in the process buggered up the bolt hole to the point where it will not be possible to oversize drill it and put in a helicoil or tap new threads. I want to weld up the hole and then drill and tap a new hole but I am wondering if the heat from the weld will ruin the seals? If I mig weld it in little bursts and let it cool in between will it cause me any problems or do I need to pull the entire thing apart? I realy don't want to have to pay to have the thing taken apart but I don't want to ruin the freshly rebuilt seals either.

Try over sizing the hole for the next larger bolt. Or weld a nut on top of the bad hole. Short welds followed by water should keep it cool. Position the rod packing as far away as possible.
good luck
pointrow

 

[AmericanLandMgt]

Ill try to get some pics when I'm up there tomorrow. The problem with oversizing the hole is that when I was drilling the easy out the drill got sideways and drilled the hole crooked. So in order to get it straight and oversized I would have to get into the o ring sealing area. I can move the rod all the way in to get the packing out of the way but the barrel seals are only about four inches from where the bolt hole is. Is that too close for comfort?

 

[pointrow]

I have JB welded a pipe coupling or something simular around a hole and welded inside while running a garden hose. Stayed nice and dry inside and cooled the surrounding metal.

 

[sheepfoot]

what's your make and model your working on, may need to remove it, pull the piston out again, have a machine shop to make you a new mounting block and weld it in place if you are that close to the oring seating area, they could knock it out quick and get you to running.