Snapped a subframe bolt

SynonymForTree · Sep 15th, 2022, 19:08

I've struck disaster and looking for some general advice.

I snapped a bolt while dropping down the subframe (front passenger side). I've got a bit extruding and I'm going to set to work to try and get it off, probably going to have a go at welding a nut on tomorrow, and if I fail I'll have to try and drill it out. Never had a bolt snap on me before so it's not ideal to be doing this for the first time on a bolt for the subframe

If I fail terribly at this, what are my options? I feel like the car is probably screwed short of getting someone to come weld on a new front left? Am I right, any other ideas?

ltec · Sep 15th, 2022, 21:09

I think it'll come out ok with the heat from the welding. It should be easier than normal to weld the nut on as you've still a couple of threads. Even when you have the nut welded on, keep welding in the middle of the nut for as long as possible to get as much heat into as possible. Then hit it with a hammer as well. The shock really helps.
If it rings off then do it again and again. Sometimes it can take 3 or 4 goes. If I can't get it off hot then Sometimes I let it cool. The heating and cooling also helps. Don't panic their is always a way.
Good luck.

ca2n · Sep 15th, 2022, 22:57

The same thing happened to my XC90 (and if I'm not mistaken the same bolt location, something to do with the other end of the bolt being exposed to the elements).

The garage had known all along that this was a potential issue and did manage to get it out. So it can definitely be done.

john langrick · Sep 16th, 2022, 10:12

Mi indie had same problem when changing engine. In my xc, my03. He managed to drill most of the Stud out, but damaged the thread it screwed into.

He then he used an old cylender head bolt screwed into the hole a d just enough thread protrided from the stud hole tofit s nut and washer inside.

So don't panic!

John l

SynonymForTree · Oct 9th, 2022, 10:11

Quote:

Originally Posted by john langrick

Mi indie had same problem when changing engine. In my xc, my03. He managed to drill most of the Stud out, but damaged the thread it screwed into.

He then he used an old cylender head bolt screwed into the hole a d just enough thread protrided from the stud hole tofit s nut and washer inside.

So don't panic!

John l

Confused slightly on this? Did he not reuse the existing subframe bolt then? Did he put a smaller bolt through that was small enough that he could get a nut on through the other side of the hole?

SnineT · Oct 9th, 2022, 11:25

Cut a blade slot in the remaining part of the bolt and use a heavy duty screwdriver blade to try and free it normally by using one you can get on a socket and breaker bar, a bit of heat around it and penetration oil should help as well, cut through the centre as well as you can.

john langrick · Oct 9th, 2022, 15:43

Hi, the bolt sheered on mine leaving a flush break.

Really no option but to drill out.

John l

Clan · Oct 9th, 2022, 15:51

Quote:

Originally Posted by SynonymForTree

I've struck disaster and looking for some general advice.

I snapped a bolt while dropping down the subframe (front passenger side). I've got a bit extruding and I'm going to set to work to try and get it off, probably going to have a go at welding a nut on tomorrow, and if I fail I'll have to try and drill it out. Never had a bolt snap on me before so it's not ideal to be doing this for the first time on a bolt for the subframe

If I fail terribly at this, what are my options? I feel like the car is probably screwed short of getting someone to come weld on a new front left? Am I right, any other ideas?

Use an induction heater loop these are extremely effective as the heat goes into the bolt rather than the surroundings, and you can get it red hot. you will need to weld a nut on first though to undo it. Did the bolt move at all before it broke? I hope you did not use an Impact gun to undo it !

darroch · Oct 9th, 2022, 17:51

Just weld your nut on. If you have stick welder turn the power up and weld inside the nut in pulses, till you bring the weld out beyond the face of nut. It will go red hot of course. If your penetration is good and weld good, it will wind out. We 'aint all got Induction Heaters

SynonymForTree · Oct 9th, 2022, 19:51

To update, mine is out now, but the threads are toast!

Trying decide the best next step - whether to just get a longer bolt and put a nut on the other side or whether to use some kind of helical insert.

Sep 15th, 2022, 22:57	#3
ca2n Member Last Online: Yesterday 09:24 Join Date: Dec 2018 Location: West Midlands	The same thing happened to my XC90 (and if I'm not mistaken the same bolt location, something to do with the other end of the bolt being exposed to the elements). The garage had known all along that this was a potential issue and did manage to get it out. So it can definitely be done. __________________ 2004 XC90 D5 SE Geartronic 195000 miles

Sep 15th, 2022, 21:09	#2
ltec Member Last Online: May 27th, 2023 22:47 Join Date: Feb 2015 Location: Northern Ireland	I think it'll come out ok with the heat from the welding. It should be easier than normal to weld the nut on as you've still a couple of threads. Even when you have the nut welded on, keep welding in the middle of the nut for as long as possible to get as much heat into as possible. Then hit it with a hammer as well. The shock really helps. If it rings off then do it again and again. Sometimes it can take 3 or 4 goes. If I can't get it off hot then Sometimes I let it cool. The heating and cooling also helps. Don't panic their is always a way. Good luck.

Sep 16th, 2022, 10:12	#4
john langrick Master Member Last Online: Today 09:50 Join Date: Dec 2016 Location: Southend on sea	Mi indie had same problem when changing engine. In my xc, my03. He managed to drill most of the Stud out, but damaged the thread it screwed into. He then he used an old cylender head bolt screwed into the hole a d just enough thread protrided from the stud hole tofit s nut and washer inside. So don't panic! John l

Oct 9th, 2022, 11:25	#6
SnineT Extrahumanestrial Last Online: Feb 13th, 2023 19:02 Join Date: Jun 2022 Location: Budapest	Cut a blade slot in the remaining part of the bolt and use a heavy duty screwdriver blade to try and free it normally by using one you can get on a socket and breaker bar, a bit of heat around it and penetration oil should help as well, cut through the centre as well as you can.

Oct 9th, 2022, 15:43	#7
john langrick Master Member Last Online: Today 09:50 Join Date: Dec 2016 Location: Southend on sea	Hi, the bolt sheered on mine leaving a flush break. Really no option but to drill out. John l

Oct 9th, 2022, 17:51	#9
darroch Junior Member Last Online: Apr 24th, 2024 20:44 Join Date: Aug 2021 Location: paisley	Just weld your nut on. If you have stick welder turn the power up and weld inside the nut in pulses, till you bring the weld out beyond the face of nut. It will go red hot of course. If your penetration is good and weld good, it will wind out. We 'aint all got Induction Heaters

Oct 9th, 2022, 19:51	#10
SynonymForTree Junior Member Last Online: Dec 11th, 2023 16:52 Join Date: May 2021 Location: Harrogate	To update, mine is out now, but the threads are toast! Trying decide the best next step - whether to just get a longer bolt and put a nut on the other side or whether to use some kind of helical insert.

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