Cracked boom Takeuchi TB153

[tomo]

You'll need to repair the crack first. Grind out about an inch past the crack to make sure you get it all. You need to grind a V with a 3/32"-1/8" gap at the root to get a 100% penetration weld. Start the weld at the end of the crack and weld back toward the side of the stick. Best would be to weld from both ends towards each other so all the weld craters are in the middle of the weld. A 1/4" or 5/16" oval reinforcement plate welded like uffex posted would add considerable strength. You want the cylinder mount in the middle. Preheat about 300F and peening the weld beads would help. If I had Mig, I would do a Mig root pass. Then use 7018 or even better 8018 to fill the V. Without Mig I would do a 6010 root pass. Some people have opened a crack up enough to put a backing strip in but a good root pass will full penetration is just as strong. You want an experienced welder to do the repair if you want it last.

Thanks for the info Dave. I will definitely make sure these procedures are used for the repair.

 

[oceanobob]

These experiences with damage to the arm, cause me to ponder invoking (or reducing) the relief pressure on the thumb protection? The reason I ask is: when I investigated the aux hydraulic on a Kubota, I noticed there was directional valve only - but no "circuit relief".

Seeing the hydraulic ram has varying displacement volume, and in that Kubota machine the Aux Hydraulic control valve is 'no flow' when in neutral position.....makes for some fiddling to readily hydraulically resolve the (over)loading issue.

As an example: I have familiarity of a Kubota 3T mini with a 'owner added thumb' that is now on the third ram - others bent when overloaded.