Problem - Bolt Corners Rounded Off

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GregGleason

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I was in the process of changing the front hub bearings on our 2003 Chevy Suburban 1500 when something bad happened. While I was torquing the one of the three hub bearing bolts (133 lb-ft) the head of the bolt was stripped, and now it cannot be tightened or loosened. I don't know how close the bolt was to the recommended torque value when things went south so I want to remove the bolt and replace it with a good one. The bolt head is (was) 15 mm. Has anyone else experienced this and if so how did you fix it? We would like to get this vehicle up and running, soon.

Greg
 
I have had some success with speciality sockets for my impact gun designed for stripped bolt heads. They have a spiral type of cutting/grabbing treads that cut into the bolt head when turned in the bolt loosening direction.

Greg
 
Most folks buy sets with 12 point sockets. Suggest trying a six point. Better grip. Make sure it's dead square on what's left of the head and turn slowly.
 

I have had some success with speciality sockets for my impact gun designed for stripped bolt heads. They have a spiral type of cutting/grabbing treads that cut into the bolt head when turned in the bolt loosening direction.

Greg

Most folks buy sets with 12 point sockets. Suggest trying a six point. Better grip. Make sure it's dead square on what's left of the head and turn slowly.

+1 for both of these. I will also suggest heat if it is feasible and/or Aerokroil
 
I have had some success with speciality sockets for my impact gun designed for stripped bolt heads. They have a spiral type of cutting/grabbing treads that cut into the bolt head when turned in the bolt loosening direction.

Greg

This is the only thing that worked for me when I had a rounded hub bolt on my Chevy truck. That, and a propane torch. I broke 3 hex sockets before I tried these things.
 
I have done quite a few hubs on 4wd's and have never seen a torque spec on those 3 bolts greater than 80 ft lbs and for a 2013 1500 suburban I find a 70 ft lb spec.
might want to double check that 133 ft lb spec.
 
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Always use 6pt sockets when possible. And ALWAYS double check the torque spec!
As far as rounded heads/nuts go, again using a 6pt socket, try the next smaller size (keep in mind it may not be metric or standard) and use a hammer to pound the socket over head/nut. Then loosen carefully...
 
If you can get a pipe wrench on it, that might work since your replacing the bolt anyways.
Hammer and a cold chisel works too, just make sure you hammer on 3 different sides into the corners.
Any kind of heat will help, even if it doesn't turn color.
 
... While I was torquing the one of the three hub bearing bolts (133 lb-ft) the head of the bolt was stripped, and now it cannot be tightened or loosened. ... Has anyone else experienced this and if so how did you fix it? We would like to get this vehicle up and running, soon.

SK "turbo sockets", as others have mentioned, will work. Plan B is removing the bolt head with an angle grinder and then using vise grips to get the stub out. Plan C—left hand drill bit and a tap.

Tig welding a bar to the bolt head is another possibility, although beyond my skill set.

Seems odd to have this issue on reassembly—are you supposed to use new bolts instead of reusing the existing ones?

Sent from my Nexus 6 using Tapatalk
 
lots of good advice above , a new 6 pt socket would do it I bet

12 pt sockets are useless for the most part here in the rust belt !!
 
Here is a picture of the troubled bolt.

Rounded.15mm.Hub.Bearing.Bolt.jpg


Thanks. That looks like something that would work.

+1 for both of these. I will also suggest heat if it is feasible and/or Aerokroil

A friend suggested heat as well. I had a bit of Kano Aerokroil left so I hit it with some of that.

This is the only thing that worked for me when I had a rounded hub bolt on my Chevy truck. That, and a propane torch. I broke 3 hex sockets before I tried these things.

Thanks for that confirmation.

I have done quite a few hubs on 4wd's and have never seen a torque spec on those 3 bolts greater than 80 ft lbs and for a 2013 1500 suburban I find a 70 ft lb spec.
might want to double check that 133 ft lb spec.

All of the sources I have seen for the Hub and Bearing Assembly to Steering Knuckle Bolts as 180 N·m/133 lb ft. The lug nuts are at 140 lb ft, and that's a smaller size stud. If you have a published resource that says something else then please let me know.

Greg
 
If there is enough room I would try a pipe wrench or vise grips even channel locks.
 
this video says 75 ft# (?) [video=youtube;37Ro3lV-vws]https://www.youtube.com/watch?v=37Ro3lV-vws[/video]

some other videos on this subject https://www.youtube.com/results?search_query=2003+Chevy+Suburban+1500+hub+ bearing+bolt

I worked at a rental yard for 18 years. Most things came loose with heat. Heat as in almost red. Other things came loose when shock loaded.

Then again, I might not be clear on which actual bolt how are having issues with.

Tony
 
OK...after some more looking around..none of them official Chevy sites....133 ft#...looks to be right. I did find one service bulletin for a change in torque for your vehicles main axle nut. From 155(?) ft# to 177 ft#.
It sounds like you're not the only one with stuck bolts. No real obvious trick to getting them un-stuck. I did find one forum where a guy did a great write up https://forums.trailvoy.com/showthread.php?t=60702
That thread is very long...27 pages.. with a lot of chatter. Maybe some good info there?

Again, I hope I think I know what you're working on.

Remember bruised and bleeding knuckles just makes us stronger...

Tony
 
Believe it or not, they used to make 6 point end wrenches. That'll get it out. Put wrench on bolt, apply torque, strike bolt head sharply with drift and hammer. Bingo.

One method would be to weld a nut to the head of the bolt, and turn it out.

At the outside, I would go to Horror Fright, buy a six point socket and a breaker bar, and use the shock treatment. HF tools are cheap, so damaging them isn't a big deal. Put the socket on the breaker, apply torque to the bolt, and have a buddy place a drift against the side of the socket, down low where the head of the bolt is, and strike it sharply. Should shock it loose. And when I say strike it, I mean strike it. Like you mean it.
 
Try this,

Soak with the following, for at least an hour, tap the area around the bolt lightly with a hammer to cause vibration giving the lubirication better penetration.

Then heat the area around the bolt with a heat gun, get close to the bolt but try to keep direct heat off, get it hot but not cherry hot, you don't want the lubricant to catch fire.

Then quickly remove the heat, spray compressed air in a can, like for cleaning a keyboard directly on the bolt, make it form ice if you can, but only only the bolt, this is a quick blast directly on the bolt!

Then use the socket described above and your arse and remove that baby!

Good luck!
 
For the OP's post it does not seem that the bolt is stuck. He rounded the head and cannot get a socket to hole so it is more of getting a grip on the head and not unsticking a bolt.

Hammering a 6 point socket on might work and would be worth a try.

I would like to know how the bolt head got rounded. What type of socket were you using; 6 or 12 point or a universal socket. It won't make any difference in removing the bolt but may help someone else in the future.
 
Thanks for the good suggestions.

At some point, the head got rounded off. It likely started with removal (we had it completely out), then the torquing it up finished it off. We were using a 12 point socket, probably from HF. I tried to get a 6-point socket at Sears Hardware (one that's still open) and Ace Hardware and all they sell is 12-point, at least in 15mm. Northern Tool may be the place to visit next, even though it's a bit of a hike to get there.

The plan is back the rounded bolt off, then put a brand-new GM bolt (got one yesterday, for about $10 - ouch) and carefully torque it to spec. I'm glad the other two bolts are back in place with the new hub bearing and torqued. It's just this one bolt that holding things up.

Greg
 
local autozone or like parts store should sell 6 pt socket separate , same with vice grips
 
Thanks for the good suggestions.

At some point, the head got rounded off. It likely started with removal (we had it completely out), then the torquing it up finished it off. We were using a 12 point socket, probably from HF. I tried to get a 6-point socket at Sears Hardware (one that's still open) and Ace Hardware and all they sell is 12-point, at least in 15mm. Northern Tool may be the place to visit next, even though it's a bit of a hike to get there.

The plan is back the rounded bolt off, then put a brand-new GM bolt (got one yesterday, for about $10 - ouch) and carefully torque it to spec. I'm glad the other two bolts are back in place with the new hub bearing and torqued. It's just this one bolt that holding things up.

Greg

Some bolts in recent model cars are intended only to be used once. They are torqued to a specific level of strain that makes it unwise to use them again.


Steve Shannon
 
It's always a good idea to go back with new bolts when torquing is required, usually a "critical" fastener. Especially on a smallish bolt like this. When torqued, a bolt stretches slightly. Its tendency to return to it's original state is what holds things together. It can only stretch so much, so many times before it snaps. And accurate torque can't be achieved on stretched bolts. I would consider these bolts to be critical.

Grab a harbor freight 6 point impact socket to go back with the new bolts.

My 1999 through 2006 Haynes manual says 133 ft/lbs also.

Mikey D
 
Well, the things I tried didn't work. Heat gun, propane torch, Craftsman damaged bolt head remover, etc. The result is an almost polished round bolt head.

Looks like I'm cutting/grinding it off.

I picked up a 4-1/2" angle grinder from HF. Anyone have any tips for this stage? Cut the bolt head off then grind or grind only?

Greg
 
Well, the things I tried didn't work. Heat gun, propane torch, Craftsman damaged bolt head remover, etc. The result is an almost polished round bolt head.

Looks like I'm cutting/grinding it off.

I picked up a 4-1/2" angle grinder from HF. Anyone have any tips for this stage? Cut the bolt head off then grind or grind only?

Greg

Before cutting or grinding it off I would try grinding flats on it so you can put a wrench on it again.
 
Grind a flat on each side of the bolt.

Then try my suggested heat and super cold method described above.

Clamp on the vice grips and back that bolt out..
 
Have you got a set of vice grips? Remove the screw/bolt used to adjust the jaws and replace it with an eyebolt. Clamp them on the rounded head as usual and grab something to put in the eyebolt, wrench, drift pin, rebar, whatever, and tighten the heck out of it. Once its nice and tight try again to back the bolt out. Loosen the vice grips before removing them or it will hurt something when they pop loose. Lol

If that fails, try the ease-out or speed-out.

As for grinding, get a cutt-off wheel for your grinder to chop the head off, easier than grinding. Try the above two first. If the ease-out doesn't work, chop off the head and drill a hole and try again.

And you can use the cut-off wheel to cut fiberglass rocket parts, its just awful dusty.

Mikey D
 
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