bolt hole stripped out

[fordman]

someone stripped out the driver side head bolt hole for the a/c bracket and the power steering pump and retapped it for a 7/16 fine thread. the fine thread is ok. but the 7/16 stud wont go through the power sterring or a/c bracket. and i DO NOT WANT TO DRILL THEM OUT. so i am goign to go look for a stud that is two different sizes on each end. 7/16 and 3/8. if i cant find that i had though of a pipe bushing. but those are pipe thread. and have a nut on them. i am out of ideas. i have a stud that fits in the hole but not the brackets. it is 7/16 coruse thread on the other end and had a shoulder in the middle. similar to a carb stud. i had thought abotu grinding the one end down to get rid of the threads. but i dont think i could get it round if i ground off those threads to make it fit.

other ideas i wont do. jb weld and redrill the hole. i have never had this work for me. ever.
is there anything else i can do? or get to make it work?

the reason i am being so picky. is because this motor may not last a long time in this truck. if i change the enigne out i dont want a bunch of junk to deal with the second time around.

[70shortwide]

have a welder? weld two studs together, a 3/8 and a 7/16

[fordman]

no welder.

will a heli coil change botl sizes for you? if i put a heli coil in the 7/16 fine thread hole could i then use a 3/8 fine thread stud inside of the heli coil?

[cep62]

Check with a company like Fastenal, somebody makes threaded bushings for stuff like this.

[fordman]

fastenal is closed today. i will check with them tomorrow. they are the last place i can check locally. everytime i go to finish this truck up something new is wrong.

[convincor]

McMaster has a threaded insert but the external thread is 1/2"-13
http://www.mcmaster.com/#93340a420/=3j7kb4
I don't think you can do it with 3/8" and 7/16" as the major and minor diameters are to close to the point there really won't be anything there to keep it together.
The drill size for a 3/8" heli-coil is listed as size "X" which is .3970
The drill size for the 7/16"-24 that's tapped know is the same size, "X".
So I would be trying the Heli-Coil route first.

[70_F100]

Here's sort of a last resort, but it could possibly work.

As convincor said, the heli-coil drill size and the 7/16 drill size is the same, meaning the tap size is probably about the same size. The difference would be in the thread pitch.

It might screw things up worse, but you could try re-tapping the hole for the heli-coil. There may actually be enough threads there to hold, especially if you clean the hole well, use Loctite primer and one of the higher-strength Loctite thread sealants.

Drill the hole to the very bottom, and run the tap in as far as you can. You may even get enough thread depth to get two heli-coils in back-to-back, then find a stud that will go to the bottom of the hole. If you use two, make sure to knock out the installation leg on the outer one before trying to install the stud. You may also need to cut off the excess, in the event that the second one doesn't go completely flush with the outside of the hole.

If I remember correctly, the stud used by Ford was pretty much a piece of threaded rod for this mount, not one that has a shoulder in the center, so this may just work.

Good Luck!!!

It would be a gamble, but at this point, you're about out of options.