The Stovebolt Site Forums The Shop Area Engine Shop Broken engine mount bolt

Hi guys,

I'm almost ready to re-install my 1956 235 in my 59, and it's time to address the broken off mounting bolt. On the driver's side, the front mount has two bolts that hold the mount to the engine. At some time in it's life, the engine had the bottom bolt break off flush with the block. The Some previous owner then decided it would be a good idea to try and drill it out. Apparently drilling in the center wasn't a good idea to him, so he drilled a 1/8" hole where the bolt threads meet the block. I know this hole is going to stop me from being able to easy-out the bolt.

Now my question, is it possible to simply leave the broken off bolt in the hole, and drill/tap the hole that has been started? If I do this, the threads will be half block, and half bolt. I know there is enough play in the rubber bushing that 1/8" off on the mount won't make a huge difference. Or do I have any other options outside of running just one mounting bolt like the previous owner did?

Thanks, Vince

Hy Coachie, I would remove the original bolt and install a new one. I know the 1/8" hole will make this trickier, but a little patience and a properly centered hole, you should be able to remove the original bolt, good luck.

I'd fill it with JB weld and then drill and tap or better yet if possible get a MIG on it fill it then drill it out enough for a smaller bolt to slip in and weld that to the original. That and the heat from the weld you should be home free.

No welder... yet. Although, I guess this might give me an excuse to argue for one with the misses... LOL

OK, I'll start drilling the center, and hope for the best. Since the PO already drilled into the block, the standard size bolt won't hold after I get this one out. I'm thinking I'll just over drill to the next bolt size.

Thanks all.

Vince

google helicoil thread repair,get them at any flaps

Maybe if you can, a stud would be a better replacement. That way you wouldn't have to mess with the thread once it was in.

yeah, "just drill it out" sure sounds good until you actually do it, particularly with that hole. Is the bolt broken from over tightening or broke from being rusted in place and wouldn't come out. Makes a big difference. If you do try to drill it use a left handed drill bit, sometimes you get halfway and it just comes out, as it is turning the right way to remove the bolt, while the right handed bit is trying to make it even tighter. You could try using a punch/cold chisel to work around the edges and get it to turn. However welding another bolt to the end would probably be the most certain way to get it out, since it isn't in the truck you could take it to a weld shop and have the professional do it for probably a lot less than the cost of a welder. Although my experience lately with the "professional" community has been somewhat strained. But like I said if it is broken because it was rusted in place you will have yourself a wonderful opportunity to use all those @!*** words you wouldn't normally get away with. I used to be in the merchant marines, and salt water, cast iron, just ordinary steel bolts, steam, and the apparent ban on never seize when assembling a ship makes for even more wonderful opportunities to practice removing broken off bolts. The preferred method for bolts you could get hold of was to heat the offending fastener red hot, then put about 4 drops of water directly in the center of the bolt and it usually came out, the flush ones usually got a bolt welded to them so you could use a wrench, the easy out was generally useless, and was not usually even considered unless it was broken off from overtightening. Most times heat was a key ingredient, but I don't know how hot you want to heat up your engine. Whatever the case when and if you get it out, the helicoil is the way to go for thread repair.

Easy outs.... Yeah I have a set... Of snapped off and broken ones. They should call them "easy headaches".