Any takers on this one?

[joemckna]

One of transaxle bolts on my 78 Sears GT was sheared when I got it. After looking it over, someone attempted to bore it out with a drill. There's not much of the bolt or original threads left and the bolt hole is ovaled out badly. I tried to get a puller to extract the rest of the bolt from the back of the hole. But there's no threads left in order to back anything out. There's also a hairline crack on the bottom of the casing that runs less then half the length of the bolt length. Trans is cast iron.

Two different machine shops recommended and said they could re-tap a new bolt hole next to the old one. Since there isn't enough room on the mount plate for a new bolt hole, this option can't be done. I asked if it was possible to weld the crack, fill the hole, re-tap and place an insert in. I was looking for something, but didn't get anywhere with them unfortunately. They didn't offer any other suggestions or solutions for working with what I have except that I might want to look into buying a new transmssion. I'm not a welder and I don't work in a machine shop, but this doesn't seem like something that's uncommon and it certainly doesn't seem like something that can't be fixed..

Could I fill the bolt hole with something such as durafix and re-tap it? I read that durafix won't work on cast iron, if that's true, is there something else I could use?


I'm stumped.. I'll throw it over to you guys, suggestions?

[ss12]

problem is two fold. cast is brittle and weld is harder then all getout. to weld cast it needs to be heated first then welded. then the weld would be so incredibly hard to tap it would be more cost efficiant to replace the broken half.

[joemckna]

Originally Posted by ss12

problem is two fold. cast is brittle and weld is harder then all getout. to weld cast it needs to be heated first then welded. then the weld would be so incredibly hard to tap it would be more cost efficiant to replace the broken half.

Thanks for the reply! When you said that it would be more cost efficient to "replace the broken half" what do you mean?

[Small Fry]

That case is Aluminummmmm...not cast iron. In less it's different then all the rest I've seen under a Suburban.

So the question is can a striped egged shaped hole (in aluminum) be filled with weld and drilled and retapped ?

Replace broken half means....replace that side of the trans case.

Ok welder's ... what say you ?

Thanks

[budgie9]

I don't know about the welding of this, but may I offer -
That you plate both sides or all four if possible bore out the hole to an over size and use a sleeve in it.
Just my 2c worth.

[Tractor-Holic]

I had one stripped bolt hole in the tranny I swapped into my Suburban..and both trannys were aluminum,zinc,or whatever,not iron..if it WERE cast iron,I'd say to BRAZE a stud into the case and cut the chassis hole into a slot so it could be assembled..but its not,so thats a moot point..

I was able to re-tap that one hole to 1/2 x13 instead of the stock 7/16 x 14 size,and had to go deep too,to get enough good threads,since the old loose bolt wallowed around in there so long it egged it out some..had to hog out that one hole in the chassis too..

If I had not been able to do that,I think I would do this..weld a nut to the chassis,and screw in a bolt after the tranny is installed..since the front mounting bolts behind the shifter take most of the torque of the transaxle wanting to pull away from the chassis,the four bolts behind the tires really act as pins,and as long as the other 3 are intact and can be torqued up good,personally I wouldn't lose much sleep over one bolt being "fudged" a bit..you probably wont ever know it..

I've seen J-B Weld Putty fix a lot of things like this in aluminum too,that I thought it never would,or last...maybe stuff some in the hole before you put the bolt in that hole along with the welded nut trick would work for you..

Depending on what exactly the tranny case is,it might be weldable,maybe not..its probably zinc like a carb is made of--some have luck using those "aluminum welding rods" seen on TV you use with a propane torch-,but I have tried them and had very poor luck getting them to work,more often than not I ended up ruining what I tried "welding" with them,it turned to a puddle of mush..thats why most welders wont touch anything die-cast.epoxy is probably as strong or stronger than the case is I bet..

[joemckna]

Lot of food for thought, thanks! I'm about to go in and get started on it since I've got some time today. I think I'm just going to going to bore/smooth the hole out(not too much on the bottom since I don't want it to crack), lube a threaded insert with JB weld(I'll make sure it's a snug, straight fit) and call it a day.

It's going to be a process to get a few of my friends that have welding experience up here and to be honest, I haven't gotten anywhere with any of the phone calls I've made or any of the shops I've visited. Haven't really gotten anywhere on the forums either... Replacing the trans is going to start venturing into spending more money that I really want to on this tractor. I'm pretty much done with it. It's painted and everything is pretty much put back together.

I'll let you guys know how it turns out. Thanks Fry and Tractor-Holic, you guys are always a big help

Originally Posted by Tractor-Holic

I had one stripped bolt hole in the tranny I swapped into my Suburban..and both trannys were aluminum,zinc,or whatever,not iron..if it WERE cast iron,I'd say to BRAZE a stud into the case and cut the chassis hole into a slot so it could be assembled..but its not,so thats a moot point..

I was able to re-tap that one hole to 1/2 x13 instead of the stock 7/16 x 14 size,and had to go deep too,to get enough good threads,since the old loose bolt wallowed around in there so long it egged it out some..had to hog out that one hole in the chassis too..

If I had not been able to do that,I think I would do this..weld a nut to the chassis,and screw in a bolt after the tranny is installed..since the front mounting bolts behind the shifter take most of the torque of the transaxle wanting to pull away from the chassis,the four bolts behind the tires really act as pins,and as long as the other 3 are intact and can be torqued up good,personally I wouldn't lose much sleep over one bolt being "fudged" a bit..you probably wont ever know it..

I've seen J-B Weld Putty fix a lot of things like this in aluminum too,that I thought it never would,or last...maybe stuff some in the hole before you put the bolt in that hole along with the welded nut trick would work for you..

Depending on what exactly the tranny case is,it might be weldable,maybe not..its probably zinc like a carb is made of--some have luck using those "aluminum welding rods" seen on TV you use with a propane torch-,but I have tried them and had very poor luck getting them to work,more often than not I ended up ruining what I tried "welding" with them,it turned to a puddle of mush..thats why most welders wont touch anything die-cast.epoxy is probably as strong or stronger than the case is I bet..