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Despite my best endeavours, I have stripped one of the Allen Headed bolts on the half shaft connection to the diff. I have managed to get 3 of the bolts out, but the remaining 3 are frozen and despite careful use of impact driver with impact head and some heat, one is now stripped.
So, i can think of 3 options:
1) i can try a stud extractor. Given that the head doesn't seem to be very hard steel, i am thinking i can drill a hole into the bolt first, so that the extractor has more bolt to work on. Once the extractor is in, i can use a breaker bar and see if the bolt comes out
2) I can try and weld a nut onto the allen head. I don't have a lot of room under the car as it is on axle stands, and my welding skills are rudimentary. I am not sure that i would be able to get much weld between the head and the nut (maybe i fill the allen head and nut hole with weld). But it would put a lot of heat into the bolt which might help
3) I cut all 3 remaining bolt heads off. Unfortunately, i think to then get the half shaft off the remaining part of the bolts, it would need to come away from the side of the car, and i think that means removing the wheel hub (which i have done before, when i replaced the wheel bearing). Once i get the half shaft off, it would then give me access to the base of the frozen bolts, so i can get heat and Sea Foam onto the part of the bolts that is frozen.
None of these options seem sure-fire. I think if options 1 or 2 fail, i could revert to option 3.
If you have had that hub assembly off recently then getting it off again to permit pulling the half shaft assembly away from the trapped stud remnants [should you go down that route] does not seem difficult.
if ultimately you are forced to cut the heads off before you do that you might want to consider using a sharp chisel to punch into the head initially and then apply a rotational force vector to try and encourage rotation. You might also consider use of a Stilson pipe wrench assuming you can get some purchase on the bolt head. Not sure that hitting the bolt head directly is a good thing considering there are bearings in the diff but then they are taper bearings or so I understand. Kind of thing our professional friends must have had to deal with from time to time.
1 UMMM are you using an air powered 1/2 inch impact gun the kind that is used to remove lug nuts?
2 OR Are you using an impact driver that your hitting with a hammer to try to turn the bolt loose?
If the second then you need an air compressor and 1/2 inch airgun with no extension.
you may need a collared extraction tool to engage the outer head of the cap screw.
NOTE if the air gun wont work then get an air hammer and work on the edge of the cap screw,
this should loosen the screw.
worst case weld your allen tool into the capscrew then hit it with the airgun
i am using a 1/2 impact gun, battery powered. Unfortunately i don't have an air compressor (but i could borrow one from a neighbour, but the neighbour doesn't have the air impact gun, so i would have to buy that).
I currently have the screw extraction tools that need a hole drilled in the bolt/screw. I wonder if the collared extraction tool might be a better way to start, and if that doesn't work, revert to the other one. What do you think?
But that set looks too cheap to be any good. The trick with any extractor is hardness, cheap chit steel won't get the job done. And internal extractors tend to expand what's left of the fastener, and can make it jam more tightly. In this case, the locked threads are likely at the far end of a long-ish fastener and if you do much drilling you will shear the head off for sure.
Have you tried getting penetrating oil to the threads from the back side of the hub?
Last edited by jcorenman; 01-29-2023 at 02:55 PM.
Reason: spelling
I have been spraying Sea Foam as best as i can onto the far end of the bolt for the last few days. I was hoping that if I heated the top of the bolt it might break the seal and slowly allow the Sea Foam to do it's work, but it hasn't worked. Oddly (perhaps), the 3 frozen bolts are adjacent - the car was off-the-road for 12 years in the UK, so i wonder if these are more corroded for some reason.
I understand your point about using the internal extractors. I also understand that the cheap external ones might not help.
I am now wondering about trying option b (welding a nut on) instead.
Those are good, but for this job I think you will need the external type, something like this: https://www.amazon.com/Impact-Remove...dp/B087P5GKFK/
But that set looks too cheap to be any good. The trick with any extractor is hardness, cheap chit steel won't get the job done. And internal extractors tend to expand what's left of the fastener, and make it can make it jam more tightly. In this case, the locked threads are likely at the far end of a long-ish fastener and if you do much drilling you will shear the head off for sure.
Have you tried getting penetrating oil to the threads from the back side of the hub?
I've had the occasion to use my set for the grub screw on rear coupler, cam bearing caps and TT clamp bolts.
On the clamp bolts I used my DeWalt 1/2" electric impact and it made it so easy. The thinner and shallower splines really get the job done.
Those Irwin external extractors have never failed me and were my first thought.
Only concern is that there’s enough room around the Allen heads. I recall they are very tight against the boot, enough that I favour a longer Allen tool to remove those bolts (when in normal situation that they’re not rounded) so the base of socket doesn’t interfere with boot and prevent being properly square onto the head.
Last time I removed half-shaft I was very worried about stripping any, so replaced all with brand new bolts of correct grade on the reinstall.
When rebuilding my brake calipers I had to get a friend to help me with welding some nuts onto the end spring screws. It was not as straightforward as we thought, initially, and we had to move to a larger nut than we initially thought. Once we did that it was child's play to remove those screws.
My point in all of this is that if you can get nuts big enough to go around the head of the bolt, and that would give you enough space to get a good wrench on the bolt, I think you're right that the heat from the welding, plus the larger head on the fastener might do the trick.
I have been spraying Sea Foam as best as i can onto the far end of the bolt for the last few days. I was hoping that if I heated the top of the bolt it might break the seal and slowly allow the Sea Foam to do it's work, but it hasn't worked. Oddly (perhaps), the 3 frozen bolts are adjacent - the car was off-the-road for 12 years in the UK, so i wonder if these are more corroded for some reason.
I understand your point about using the internal extractors. I also understand that the cheap external ones might not help.
I am now wondering about trying option b (welding a nut on) instead.
Ian, the three machine-screws that came out: How did they look? Was there any corrosion? Along the unthreaded shaft, or just at the threads?
Some photos of those fasteners that came out may show some clues.
Certainly, if the car sat for a couple of decades, anything could happen-- moisture getting to the bottom fasteners but not the top ones, who knows...
Your previous thread indicated no movement at all. That suggests corrosion along the length of the fastener, not just corroded threads. If it were only the threads that are locked, then the shaft would twist a bit-- experienced fingers would feel that. But not at the far end of long socket extensions-- those twist also. (Which is why impact wrenches are much more effective when close to the fastener).
One thing I like to do with stuck fasteners is to go back and forth-- if it doesn't want to loosen then try a tug in the opposite direction-- back and forth. If there is any movement at all, that will help the anti-seize to wick in. That's a real limitation of extractors-- internal or external-- they only loosen. A welded nut-- or even vice-grip pliers if you can get them in there-- will go both ways.
The best anti-seize is a mix and acetone and ATF by the way. Kroil (kroil.com) is also very good but may not be available in the UK. I don't know how Seafoam compares. Heat may also help break up the corrosion, as mentioned.
Ian, the three machine-screws that came out: How did they look? Was there any corrosion? Along the unthreaded shaft, or just at the threads?
Some photos of those fasteners that came out may show some clues.
Certainly, if the car sat for a couple of decades, anything could happen-- moisture getting to the bottom fasteners but not the top ones, who knows...
Your previous thread indicated no movement at all. That suggests corrosion along the length of the fastener, not just corroded threads. If it were only the threads that are locked, then the shaft would twist a bit-- experienced fingers would feel that. But not at the far end of long socket extensions-- those twist also. (Which is why impact wrenches are much more effective when close to the fastener).
One thing I like to do with stuck fasteners is to go back and forth-- if it doesn't want to loosen then try a tug in the opposite direction-- back and forth. If there is any movement at all, that will help the anti-seize to wick in. That's a real limitation of extractors-- internal or external-- they only loosen. A welded nut-- or even vice-grip pliers if you can get them in there-- will go both ways.
The best anti-seize is a mix and acetone and ATF by the way. Kroil (kroil.com) is also very good but may not be available in the UK. I don't know how Seafoam compares. Heat may also help break up the corrosion, as mentioned.
01-29-2023, 11:17 AM
Stripped Allen headed bolts
