Broken motor mount bolts into the block?

[leoJr]

Seems this has happened to others too. Both motor mount bolts are broken flush with the block on the passenger side.

1999 5.0, auto trans, rear wheel drive.

It looks like I have a straight line to get a drill and easyout to them. I'll lift it from the top as I do have an engine hoist and this will give me more room underneath to work in.

Anyone have thoughts as to why the factory bolts snapped off or suggestions that might make this task easier?

 

[C420sailor]

I have one snapped off. I didn’t fix it. I don’t drive the truck hard at all, no problems as of yet.

That said, I would probably try to build up a nub with MIG/stick and then weld a nut onto that, and extract it that way. It’s tight in there, but looks doable. The block is cast iron, and I’ve had great results pulling steel fasteners out of cast iron this way. I had a starter bolt snap off below the surface. Was able to build it up with TIG (lift start works well, had enough access for a TIG torch) and get the nut welded on that. The welding gets the bolt cherry red, which helps with extraction.

Easy as pie if you pull the engine, but that’s a PITA

 

[leoJr]

I have one snapped off. I didn’t fix it. I don’t drive the truck hard at all, no problems as of yet.

That said, I would probably try to build up a nub with MIG/stick and then weld a nut onto that, and extract it that way. It’s tight in there, but looks doable. The block is cast iron, and I’ve had great results pulling steel fasteners out of cast iron this way. I had a starter bolt snap off below the surface. Was able to build it up with TIG (lift start works well, had enough access for a TIG torch) and get the nut welded on that. The welding gets the bolt cherry red, which helps with extraction.

Easy as pie if you pull the engine, but that’s a PITA

Thanks for the suggestion! I do have a wire feed. If this engine comes out it is getting rebuilt as it has 230k miles on it.

Interesting that your one or my two snapped off.

 

[C420sailor]

I suspect that my truck was involved in a front end collision and rebuilt. I think that, coupled with corrosion, may have contributed.

 

[tinman_72]

My '99 2WD 5.0 has this issue on the passenger side. Since (at the time) I planned to pull the engine in several months I just chained it down on that side. It is on an engine stand now, awaiting installation into my '73 F100.
The engine has yellow markings on all the major parts so I assume this is a junkyard engine. I assumed someone was in a hurry and used an impact to install the bolts.

 

[rabbit91]

I’m curious how the repair went. Found my drivers side snapped off today

 

[leoJr]

I’m curious how the repair went. Found my drivers side snapped off today

This repair was much easier than I expected.

I used a jack under a 2x4 under the oil pan to take some weight off the mount. Not all of the weight, just enough to get some movement of the mount with a pry bar. This let me line up the broken bolts within the mount holes.

I had tack welded a center punch to a piece of scrap metal as I thought an easy out (or similar) was going to be needed and I wanted to start the drilling in the center of the stud. The really long center punch was needed as I couldn't get a good hammer swing way up by the motor mount. Turns out this was not needed.

Maybe hitting the studs with the center punch loosened them but with the motor mount holes aligned with the broken bolts I was able to slowly spin the broken studs with the tip of a screwdriver. I am blessed to live where rust is rarely an issue.

 

[rabbit91]

This repair was much easier than I expected.

I used a jack under a 2x4 under the oil pan to take some weight off the mount. Not all of the weight, just enough to get some movement of the mount with a pry bar. This let me line up the broken bolts within the mount holes.

I had tack welded a center punch to a piece of scrap metal as I thought an easy out (or similar) was going to be needed and I wanted to start the drilling in the center of the stud. The really long center punch was needed as I couldn't get a good hammer swing way up by the motor mount. Turns out this was not needed.

Maybe hitting the studs with the center punch loosened them but with the motor mount holes aligned with the broken bolts I was able to slowly spin the broken studs with the tip of a screwdriver. I am blessed to live where rust is rarely an issue.

Thanks for the quick response ! Glad it was smooth for you, do you remember what pitch and size bolt? I would like to pick up some grade 8 bolts to replace them with

 

[leoJr]

Thanks for the quick response ! Glad it was smooth for you, do you remember what pitch and size bolt? I would like to pick up some grade 8 bolts to replace them with

I do not. I took the pieces with me and matched them at the hardware store. I really expected the bolt extraction to be a much longer task. If I would have known they would spin right out I would have had new bolts already in hand like you are trying to do. Apologies.

 

[rabbit91]

I do not. I took the pieces with me and matched them at the hardware store. I really expected the bolt extraction to be a much longer task. If I would have known they would spin right out I would have had new bolts already in hand like you are trying to do. Apologies.

No problem! Once I find out I’ll post

 

[rabbit91]

Drivers side 7/16 - 14 bolts 1” length.

I centered the motor mount, center tapped as best I could. Started drilling with left handed drill bits and the second bit it started unthreading the bolt. Hope this aids someone in the future