Welding loose "bosses" into an excavator counterweight

Date 05-01-2015 04:23

Have a equipment rental/ sales company that has a Doosan excavator...... The threaded "bosses" that hold the counterweight on the back of the machine are loose...... The bosses are about 5" in diameter with a 1" threaded hole in them...looks like they are press fit, but now are loose.. This is causing the mounting bolts to loosen up and fall out while under use..... Had manager at equipment co. call Doosan about a weld procedure / fix ,but they aren't being any help....Anybody have any suggestions on weld rod selection, heating, etc. .......Looks like the counterweight is cast steel and the bosses are also steel.......Thanks in advance, Bob @ Ambridge Weld & Fabrication

By Cumminsguy71 (*****)

Date 05-01-2015 11:40

They probably won't be much help unless you contact Doosan on your own, maybe they have a US contact.

As far as welding, I've walked behind counterweights but that's it. Rental companies, "just weld it" is what comes to mind after several years of being employed by one and seeing the "welder" they hired to do repairs and what kind of bird sh.....I mean beads he laid down.

I see a Doosan dealer here in Nashville, Doosan USA on a Google search. You might call a dealer that works on Doosan excavators and see if they can offer any info or maybe give you contact info for a regional guy of some sort for techy info. Knowing type of steel at least would be a good start.

By 803056

Date 05-01-2015 18:57

Drill a hole in the boss and the excavator frame. Collect the drilling chips in separate plastic bags and send them to a lab for chemical analysis so you know exactly what you are dealing with. You can then make some sound decisions based on the results of the chemistry of the frame and the bosses. The cost of the chemical analysis is much less than paying the medical or funeral expenses because the materials involved have poor weldability.

It would not be all that surprising to discover the bosses are similar to an AISI free machining steel, Ouch! That could be why they are not welded to begin with.

Best Regards - Al

By theweldor (*)

Date 05-01-2015 23:17

First question - Are the threaded bosses welded to the house or to the counterweight. I haven't encountered any Doosan equipment but have repaired several Cat, Kobelco and Kamatsu equipment. Another option is to drill the threads out and thru bolt them with a good grade bolt.