Don Young wrote:

The worst part so far is getting all of the broken welds and reinforcements
removed. Some bolts that were supposed to hold the rails to the castings
were stripped, oversized, restripped, and had their heads welded to the
rails. Of 16 blts into the castings, 2 were the original 1/2" size. Some
were 5/8", some were 3/4" and even the 3/4" ones were stripped. There is a
lot of intact reinforcing that is impractical to remove. I would buy new
frame rails if available but they aren't. Luckily I have a nearby welder
friend who has an air arc system. It uses a copper coated carbon arc to melt
the metal and an air jet to blow it off. Because of all of the damage and
repairs poorly done, along with all the reinforcement making the rails very
stiff, it is difficult to get everything realigned properly. I have made
threaded bushings to reduce the oversize and stripped casting holes in the
front crossmember and bell housing, using epoxy and what is left of the
hole threads to help hold them in. In some places I had to plug the
stripped, oversize and crooked holes and re-drill and tap. It is a real
challenge and going pretty slow, but I will get it done.

That sounds like a really challenging project. In welding terms, much
more challenging than my machine. There is no damage to the tractor on
my machine and the frame rails do not appear to be distorted. The worst
cracks are about 2" long, and in a backhoe boom which is about 16" deep,
they don't look like a problem at the moment. Someone has repaired the
dipper before. A fair repair I think. Perhaps not perfect, but it hasn't
cracked again. Some day I would like to restore the machine completely
and get the cracks repaired by a professional welder.

Can you tell if the damage to your machine is just the result of
fatigue, or has it been caused by overloading? I've never seen a digger
with damaged castings before. Does the tractor itself carry the digging
and loading forces, or do the frame rails run from front to rear?

Here are a couple of pictures of my machine. The first shows the 2"
cracks in the backhoe boom. The second shows the repaired dipper:

http://www.mythic-beasts.com/~cdt22/jcb_fatigue1.jpg
http://www.mythic-beasts.com/~cdt22/jcb_fatigue2.jpg

It is heartening that you have the perseverance to pursue your repair
project. Drop me an e-mail if you have time to take any pictures!

Best wishes,

Chris