Broken rear engine mount bolt. How screwed am I?

[jvincig01]

Gentlemen,

I really screwed up today. I finished a long day of installing my engine and transmission. Once they were in, I had to connect the rear engine mounts to the bell housing (there are 6). When I was tightening the very last one, I snapped it off. I am beyond mad at myself right now. So my questions are...

1. Do I pull the engine out again and drill out the broken bolt?
2. Do I leave it and roll with 2? It's the rear driver side.
3. Do I go with 2 - 12.9 grade bolts on the rear and call it a day?

 

[Feistl]

How much room is there? Can someone get in with an air drill?

I've seen some professionals do amazing work getting broken bolts out of tight spaces. Not sure what prices are like over there, but I've had bolts removed for ~$100 including call out fee...

 

[reddingcruiser]

Support the engine/tranny and pull the mount. You may be able to:

• walk the broken piece out with a chisel
• Grab the piece with vise grip
• Weld a nut on the end and unscrew the broken piece
• IIRC, the threaded hole goes through the bell housing and you may be able to access it from there also.

 

[reddingcruiser]

If the threads aren't messed up and were clean when assembled, the broken piece should come out fairly easy.

 

[jvincig01]

Support the engine/tranny and pull the mount. You may be able to:

• walk the broken piece out with a chisel
• Grab the piece with vise grip
• Weld a nut on the end and unscrew the broken piece
• IIRC, the threaded hole goes through the bell housing and you may be able to access it from there also.

All good ideas! thanks! My only concern is being able to access the remaining bolt. It looks like the head snapped off at the worst spot which doesn't leave me with anything to grab onto once i remove the mount. Here is a pic.

 

[jvincig01]

How much room is there? Can someone get in with an air drill?

I've seen some professionals do amazing work getting broken bolts out of tight spaces. Not sure what prices are like over there, but I've had bolts removed for ~$100 including call out fee...

Not a bad idea. Thanks!

 

[reddingcruiser]

Patience, Grasshopper! Pull the engine mount off and reassess. No matter what you do you'll need it out of the way.
If you don't own a cape chisel buy a good quality one that will hold a point. If any part of the bolt is flush with the surface you have a chance of walking it out.

 

[jvincig01]

Patience, Grasshopper! Pull the engine mount off and reassess. No matter what you do you'll need it out of the way.
If you don't own a cape chisel buy a good quality one that will hold a point. If any part of the bolt is flush with the surface you have a chance of walking it out.

a cape chisel eh? im going to look into that. i might be able to make a groove in the bolt from the inside of the bell housing. just enough to put a screw driver in it and walk it out.

 

[3_puppies]

that bolt was cracked to start with, it should not have broke off, if you look at the broken end it is most likely not a clean break.

you can use a small engraving tool also to thread out a broken bolt,
was it going in easy then tightened when the head got to the mount?
it should come out easily.

 

[Jdc1]

Anyone think that looks like the wrong thread?

 

[65swb45]

Anyone think that looks like the wrong thread?

No, those particular bolts are coarse thread from the factory.

Josh, the driver's side is the torque side, torque comes from the rear forward, and those bolts are on a side load. I would not run it on two. And yeah, it sucks position-wise. Firewall brace is right there, which is one of the reasons people don't keep up on keeping the pucks tight.

 

[jvincig01]

No, those particular bolts are coarse thread from the factory.

Josh, the driver's side is the torque side, torque comes from the rear forward, and those bolts are on a side load. I would not run it on two. And yeah, it sucks position-wise. Firewall brace is right there, which is one of the reasons people don't keep up on keeping the pucks tight.

Thanks, Mark. I am going to give it a try this weekend and see how it goes. The cruiser is up at my father inlaws (an hour away). My plan is to go there with a list of ideas and just take my time and think everything through. I am feeling more confident about being able to take it out.

Because I only have the one broken bolt with me, you wouldnt happen to know the size of the bolt would you? I dont know how long it is. I am thinking about grabbing 6 new 10.9's and putting them on once i get this one out.

 

[65swb45]

If you'd asked me yesterday, I could have easily grabbed one off the shelf. I won' be back in the shop now until Monday or Tuesday.

 

[65swb45]

Josh

I just remembered I had a set re-zinced for the SWB, which is here at the house with me.

1.75 pitch, 30mm under the head.

 

[jvincig01]

Josh

I just remembered I had a set re-zinced for the SWB, which is here at the house with me.

1.75 pitch, 30mm under the head.

Thanks! you just saved me an hour drive

 

[jvincig01]

that bolt was cracked to start with, it should not have broke off, if you look at the broken end it is most likely not a clean break.

you can use a small engraving tool also to thread out a broken bolt,
was it going in easy then tightened when the head got to the mount?
it should come out easily.

I think you might be right about the bolt being cracked. I was just tightening it and it never really felt like I had enough pressure on it. I did 5 before with the same amount of strength and they felt completely locked down. This one still felt like i had several more turns to go before it broke off.

 

[CHCP]

How many times I've felt a bolt ready to break but kept turning it. I've had good luck with left hand drill bits.

 

[jvincig01]

Josh

I just remembered I had a set re-zinced for the SWB, which is here at the house with me.

1.75 pitch, 30mm under the head.

Just found them at my local Ace Hardware. I picked up 6 new ones. They sure look pretty! Thanks again!

 

[73FJ40]

Just found them at my local Ace Hardware. I picked up 6 new ones. They sure look pretty! Thanks again!

View attachment 1319619

Careful, @Coolerman's bolt and nut spreadsheet indicates 19 mm heads won't fit, the JIS OEM ones have 17 mm. Maybe the one that's broken will fit okay.

Or, maybe Coolerman's spreadsheet is for the 3 speed bell housing, and the 4 speed has more clearance.

 

[jvincig01]

Careful, @Coolerman's bolt and nut spreadsheet indicates 19 mm heads won't fit, the JIS OEM ones have 17 mm. Maybe the one that's broken will fit okay.

Or, maybe Coolerman's spreadsheet is for the 3 speed bell housing, and the 4 speed has more clearance.

Good tip. Thank you. I will grab a JIS one just in case.

Josh