Drill and tap ring gear bolts?

[threewood]

Bought a ring and pinion gearset on another board from a guy swapping to shorter gears. He called me today and said the shop doing his rearend snapped all twelve bolts. They didn't realize they were left hand thread (after snapping all 12, and were marked L on bolt heads). Set is for a Mopar 8.75"

He offered a deeply discounted price or full return. I figured I could give it a go and took the discount. I enjoy a challenge.

Will I have issues drilling and tapping these? Planned to tap to a smaller, right hand thread , insert bolt and twist out. How hard are these bolts?

 

[Milton Shaw]

Should just drill out with a low speed drill and a lot of pressure. If they are left hand then they will unscrew with a regular drill bit. Normally when broken from over tightening they don't mess up any threads just snap the shank of the bolt. Thy that or just slot them with a dremell and use a screwdriver on them.

 

[Kevin54]

The bolts are heat treated, so you will have some difficulty. If the heads are snapped off close to flush, you may want to try and weld a nut to them. Most are made from Chromoly. If you decide to drill and tap, use a good 2 flute gun tap, and go as big as you can. Plus go a drill size larger so you don't have so much to tap. Instead of 75% thread, try a drill size that will give you around 50% thread. Reducing the percentage of thread depth will make tapping easier. Plus going as larger as you can will make sure the tap is stronger.

You'll be able to tell how hard the bolt actually are when you spot them with a center punch. If you decide it is too much to do, let me know, and I can most likely get them out for you using a mill and a carbide endmill. And as long as they are all accessible there would be no problem in doing that.

 

[Rookie2]

It's doable , chances are that 10 will come out easy. I've drilled out cat 943 track bolts out so never say never.

 

[threewood]

Thanks for the replies!

I'm hoping that they come out just drilling into them, best case. They are original to the car, mid 60's so I'm not sure if they came loctited from the factory. Good advise on tapping them. I don't have them in my hands yet so I don't know how much of the stud is pretruding. I would think the holding power would be in the bolt head, which is gone. I'm still in awe that a rear end shop didn't stop and scratch their chin after the second one busted. They are marked with an L on bolt head. I would have at least hit the third one with the flame hammer.

 

[Capt Chrysler]

If they are a mid 60's gear set. The old grease may have covered the L up. Good luck on a used gear set. I always seem to have just a tickle of noise when I do one.

Capt. Chrysler

 

[threewood]

If they are a mid 60's gear set. The old grease may have covered the L up. Good luck on a used gear set. I always seem to have just a tickle of noise when I do one.

Capt. Chrysler

Really no other option and keep the 741 housing. Gearset is a 3.23 which is not made anymore for this case. It's going in a street cruiser and will see some highway miles so I wanted to stay away from anything lower that would require taller wheels. Coming out is a 2.76 which is good for driving but not good with my soon to be engine build.

 

[TLCObsession]

As suggester - plain steel nuts if you can find them. Hold over the broken bolt and weld away. Piece of cake.

 

[trackwelder]

Sounds like quite a bit of drilling. I would weld a flat washer on then weld a nut on to the washer. Back them out with a wrench or ratchet.

 

[Olafur]

Someone was in a hurry snapping all 12!!

Like stated above weld a nut (or first a washer and then nut -sometimes easier). I would expect all 12 to be out in about 15 minutes since there are probably no rust issues and the heat from the weld is going to soften up any tread locker if existent.

 

[raddksn]

I've had great success with welding a nut on then backing out with a ratchet.but I let it cool before trying.

 

[yaidunno]

TIG welding some sort of nut to the protruding stud will be the easy solution to removing them.

After the welded stud is red hot and cools, it will have shrunk. This will further help in removing the fasteners.

 

[Alta_Racer]

Try just tapping them with a pointed punch and hammer first. U might get lucky. I would apply a little heat, as I always locktite them myself.

 

[toplessHO]

heat will destroy any loctite left

 

[Mr.N]

after snapping all 12, and were marked L on bolt heads

Time for a new shop?

.​

 

[Spareparts]

Operator broke 7- 1/2" bolts on the rotation joint of a brand new Altec digger truck trying to pull pole butts with the boom cradled. Problem was that they broke almost 1" into the hole, talked to my welding supplier for help. He suggested a welding rod from MG # 660 1/8". He hopped in his truck and brought some to the shop. We placed a washer and nut on top of the hole and inserted the rod straight in to the center of the hole and "DID not move it at all, just burnt it straight down. Took 2 1/2 to 3 rods to reach the washer and nut and worked the rod around the nut to the top. As soon as we reached the top of the nut we hit it with a impact and out they came. While we were getting the bolts out I sent my parts guy to St. Joe. to Altec to get a new set of bolts. All said and done the job took 4 hrs. verses 3 to 4 days for Altec to do it. The biggest kick in the pants came about a month later when the owner came down to the shop with the invoice for the welding rods and having a fit about spending $30.00 a lb. for welding rods. No explaining wouls make him happy so I gave him 2 of the welded bolts to look over, but with most owners he went away still fuming. That is one of the many reasons I don't work there any longer.

 

[kkroger]

Stud Plus Welding Rod or Wire...

http://www.esabna.com/us/en/products/index.cfm?fuseaction=home.product&productCode=1066

 

[Rookie2]

Thanks ! SPAREPARTS & KKroger


This is why I love this site ! I learn stuff !

 

[scraptor]

If they are a mid 60's gear set. The old grease may have covered the L up. Good luck on a used gear set. I always seem to have just a tickle of noise when I do one.

Capt. Chrysler

It ain't a mopar if it doesn't whine on deceleration.
Try a normal rotation drill bit about half the bolt size first, try to get it centered. If that fails go to the welding a nut ontop of the broken bolt.
Drilling and re tapping is a last resort, really easy to drill off center and wreck the holes in the ring gear.

 

[Shadowdog500]

I bet they will come right out! They have been in gear oil for years so there is no corrosion.

They were simply over torqued to failure by some idiot with an impact gun.

I use the straight pick from my crafstman 4 piece pick set (shown below). Take a small tack hammer and place a dimple in a natural groove or crevice in the broken bolt out nEar the edge of the bolt.

Then angle the pick and tap it with a hammer to work the broken bolt out in a clockwise direction. This technique is the first I try and it usually works great on bolts that snap from being overtorqued.

Chris

 

[threewood]

Success! They came out easier than I would have imagined. The bolts were sheared off below the ring face and jagged. The ones that were semi-flat I drilled down and the broke bolt spun out with the bit. There were a few that while drilling weren't pulling out like the rest so I tapped an allen head into the drill hole and removed them. About 4 were so jagged I don't think I could have got a centered drill hole in them. But they were jagged enough to catch a flathead screwdriver, so I unscrewed them. Took about 30 minutes for all 12 as I took my time. Threads still look good. Now to mount it up to my new Eaton TT differential.

 

[Ohmthis]

Great! Glad you got them out and also posted what worked for you. I will let someone else have some proven methods.

 

[NUTTSGT]

Success! They came out easier than I would have imagined. The bolts were sheared off below the ring face and jagged. The ones that were semi-flat I drilled down and the broke bolt spun out with the bit. There were a few that while drilling weren't pulling out like the rest so I tapped an allen head into the drill hole and removed them. About 4 were so jagged I don't think I could have got a centered drill hole in them. But they were jagged enough to catch a flathead screwdriver, so I unscrewed them. Took about 30 minutes for all 12 as I took my time. Threads still look good. Now to mount it up to my new Eaton TT differential.

Another interesting idea, tapping an Allen wrench into the drilled hole. I'll remember that.

 

[whyNick?]

Another interesting idea, tapping an Allen wrench into the drilled hole. I'll remember that.

The guy who ran the shop where I worked in college swore by this method, I've used it a few times since then and it works pretty well. It also gives me a use for the entire drawer of hex keys that seem to multiply in the dark like tribbles.