Engine to Transmission Bolts

So the heads just snapped off the bolts or do you have part of the bolt shank attached to the head If that's the case when you pull the transmission back you should have essentially somewhat of a stud sticking out maybe you'll be able to spray some penetrant like croil let it do its job and soak in well and maybe you'll be able to back them out with a good set of knipex pliers or something. If it broke off flush with the back of the engine then you'll be it peaning or center punching and drilling grab a set of left hand drill bits always helps with this kind of stuff at least you're turning in the right direction to be loosening the piece or removing the piece so that's kind of a plus If not you can just drill it with right hand drill bits and start small and work up and then chase the threads out and new bolts shouldn't really be an issue You have one or two that aren't broke so you should be able to match them up or drop by a Pick-A-Part and grab a few from another car with somebody's dropped the transmission or done whatever and just left the bolts on the ground pretty common it a lot of those Pick-A-Part places and I would imagine all gas car like a Yaris or a Scion x series car the bolts will be the same The car just won't have hybrid system bell housing from the transmission is the same again so you can find those bolts pretty easy I have no idea what the specs are but in the morning I think I have one or two laying out here.

 

The same thing happened to me this summer when I was doing an engine swap. The three lowest bolts snapped. One broke so that nothing protruded from the threads the other two snapped at the heads. I was able to get the engine off and tried to extract the bolts. They were completely frozen in there. This 2010 car has spent its life in Maine so I am in the salt belt. At first I used a left-handed drill, but the tip got damaged partway through the bolt and I could not proceed. I tried using a vice grips and penetrating oil and heat (MAPP) to extract one of the now protruding studs, and that one also broke at threads. I was able to drill that one all the way through using a cobalt drill bit. I fully tapped that hole, and tapped as much as I could of the partial hole made with the left-hand drill bit. I left the third one protruding as an extra alignment stud for putting the engine back on.

The bolts are M10 with 1.25 pitch. I believe the longer ones are around 50mm, but don't quote me on that. I put a stainless steel one in the full length hole and a zinc coated one in the partial hole. I figured that I was OK with 1.5 bolts out of 3 on the bottom.

If I could do it again? If I had acetylene I would have tried that when the first one snapped, but no amount of MAPP and penetrating oil could have gotten any of them out on my car. I would not use a left-hand bit again, and would go straight to cobalt. Cheaper than left hand, and there would be not point since there was no way the bolts were actually going to come out.

 

What were you using to break them loose, breaker bar, impact wrench?

 

Yes if you know as a mechanic and a common sense person that there's no chance of the both stud coming loose then that's would be correct go straight to a drill bit that will drill it out I usually start with a small very small because it makes a hole very quickly at high speed with a little lubricant and then taper on up until your wallowing out basically the minor diameter I think that's right or the major diameter where you're just touching the tips of the threads with the last drilling then you can chase that with a chaser or if you have a tap in the appropriate size or a dye whichever is appropriate You're good Western Massachusetts where I was for many years was the same way as Maine It is tough on stuff

 

Breaker bar. Then I tried to loosen one of the new "studs" with a pair of vice grips with a pipe on the end.