TEA20 underneath the diff

[kaesark]

Hi
Looks like I got another job to keep me busy. Before I attempt to tap out these sheared off bolts, can I rest assured they don't go all the way through into the diff housing.
Thanks

 

[ghostdncr]

I can't answer that question specifically but according to common machining practice... If that upper left hole goes all the way the way through, they all do. If it's a blind hole, they all are.

If it were mine, here's how I'd go about it for minimal fuss and risk of messing something up. Dot the center of the broken bolts with a good, sharp center punch. If I try to hurry past that step, there's little doubt the drill will walk off center and probably get into the threads. Next, I'll use a small diameter drill like a 3/32" to drill a pilot hole 1.5 to 2 x the diameter of my finish drill, i.e. if I'm finishing with a 1/4" drill, the pilot hole would go about 3/8 to 1/2" deep. Drill the finish hole til it bottoms out in the pilot hole.

Lightly tap an EZ-Out into the hole that will fit about halfway into the depth of the hole. It will twist into the hole deeper as it bites in during the next step. [u:1dab91578c]Use a tap wrench[/u:1dab91578c] to turn the EZ-Out because that will exert an even torsional force to the EZ-Out. Crescent wrenches, vice-grips, and the like will exert excessive force on one side and twist the extractor to one side, leading to cussing, busted knuckles, and a failed extraction. Done properly, you'll have those bolts out in no time.

 

[Charles in Aus.]

This is a very common problem Kaesark , getting them out is no fun .
Drilling is the usual method , otherwise welding onto the stump through a nut and washer works as well , there are plenty of good You tube clips that explain it . The heat from the welding loosens a lot of the corrosion holding it as well .

The bolts should not be there in any case , the proper fastener to use is a double ended stud . UNC into the casting and UNF on the outer . The UNC thread holds better in the Spheroidal , nodular cast iron of the transmission case , the UNF gives much more leverage in order to attach the draw bar or Auto hitch assembly .
You can use bolts but be very careful , the cast iron at the end of the blind hole is very thin, a bolt even slightly over long will pop the end into the housing and you will have a leak that will drive you mad . Be careful with grease oil or never seize on the threads as well , these lubricants can cause hydraulic pressure enough to pop the end off as well . By the same token if drilling be really certain you don't go past the end of the sheared end or you might end up with eight gallons of oil in your face :shock:

 

[John Deere D]

I have backed a TEA-20 as well as a MF 35 up my trailer ramps to gain a bit of working room.
Buffed off all rust,paint,etc..
Then attached a flat washer (several passes)to the broken off fastener...7018 Rod.
After approximately one hour another pass of 7018:

Then attached a NUT to the washer with 7018...

After approximately one hour tapped (shock treatment) nut with hemmer....

With a 1/2" drive impact gun (set on low torque)applied force CCW...CW...CCW...CW and broken fastener threaded out:

Possibly I was lucky?

Grounding lead from welder was placed on head of cap screw threaded into bore after chasing threads in bore with bottoming tap:


Bob...Retired Power Engineer...
.