Broken Attachment Bolts on older JD 4030

I am attempting to help the barn owner where our horses are.
She has/boards 30 horses.
We have been there about 2 years with our horses.
She is 73 and is now by herself, lost husband a year ago.
I now help her as much as I can with things as well as money for repairs, hay .
She has a JD and I think that it is a older 4030 with a Bush Hog loader on it.
As I was moving roll bales the front bar that attaches to the JD dropped down. After looking at it the bolt that attaches the cross bar to the front of the JD sheared off.
I had not noticed this before now but the other bolt at sometime had done the same thing and by the looks of things it broke sometime ago.
There is only two bolts hole on the front for any attachment.
So i was looking to repair the problem by drilling and re-tapping the two bolt holes on the front of the JD.
Well needless to say that did not work. Unable to drill steel on the JD.
I got a hold of a welder and he has been out twice and leaving tell her that it will take a special type of welding material to make repairs, not sure if he is telling the truth or not.
So question, how can this be repaired?
Tractor is down and the manure is piling up.
Thanks to all for and help solving this issue.
Mark Bell
Plainfield, In

Welcome to YT
Many broken side frame bolts on JD tractors have been drilled & replaced with new bolts. If threads are bad one can install heli-coils. Can you take any photo's of damage?

Sorry no pics available.
I apologize if I did not mention, these are the front bolts not the side bolts/ Side bolts are OK.
More details,
I was able to remove the old bolt using the step-up drill bit process. Not much was left inside the bolt hole.
The threads in the hole are rounded and will not support a replacement bolt.
I attempted to drill deeper into the tractor using a good bit (using a 1/8 bit) with oil for around 2 hrs (on one hole) with little change.
Part of the problem was that the owner told me that the bolt that was in the tractor was a 5/8 #8, so I got a 7/8 8 thread tap and required drill bit.
After on site I realized that the old bolt was 7/8.
That is why I tried to drill deeper into the tractor.
So you see the problem i have. If I try to go to a large bolt I am not sure that I can drill out the hole and then get it tapped.
This is why a welder was called. He had told the owner that he was unsure if he could weld due to the steel that the front of the tractor is made of, cast steel I think is what he said.
So with this information I hope that all have a better idea of what I tried.
Should I try to go up to a 1" bolt, or should I let the welder try to fix?
Thanks

Did you get both broken bolts out? The holes in the front should be able to be drilled out and either oversized or repaired with thread inserts. What do you have to drill with? You may need to get some good bits, better than the local hardware store variety.

Regarding size and thread pitch. Coarse thread 7/8" is 9 TPI. 3/4" is 10 TPI and 1" is 8 TPI. The 5/8 #8 you referred to was likely a 5/8 grade 8 bolt. Grade 8 can be hard to drill by hand.

You may be able to go to 1"-8 TPI, easier than going deeper. The tap drill for 1"-8 NC thread is 7/8", so there is not much material to remove from the existing holes if they are 7/8" thread. You will likely want a tap set (starter, plug, and bottom) to thread the holes with. You will also likely want a 1-1/16" bit to open up the holes in the frame for the 1" bolts.

Have someone with the proper drill and knowledge evaluate what's left and drill and tap for the appropriate sized "threaded insert".

You can GOOGLE "threaded insert" to see what I am suggesting.

Had you called the weldor BEFORE messing it up, he could have welded a washer to the remains of the bolts, then welded a nut to the washer, and after letting them cool, likely they would have easily unscrewed.

I had the same problem as you on a 4630.
Bolts got loose on frame rails and egged
some holes in the block and front bolster.
I rented a magnet drill press and drilled
them to 3/4" if I remember right then put
the heavy cast iron thread inserts in to
accept the 5/8 frame bolt. It sucked but
seemed to work good. I got the inserts
from granger.

Try a salavage yard. AR67473
Untitled URL Link