Suspension: Broken Subframe Bolt

[AidXC90]

I also have no option either

[Bob Meadows]

Call or phone your local engineering supplier and ask for the tapping drill size for the appropriate bolt dia. (information is probably on line as well)
If you can get the final drill hole as close as possible to the required undersize then the remaining threads can be picked out or in a coil- sometimes quite easily.
Quality drills are a must & lubricant- don’t use the stud extractors as recognised: ~
With a little luck you may be able to avoid tapping the thread.
If the hole gets completely mangled it’s not the end of the world!! Come back for a solution but go carefully and you will do it properly.
Copper grease the new bolt- the next owner will love you!
In this situation you seem to have the best advice from members-Good Luck
Bob

[dstc]

I don't like drilling out bolts, too messy, not enough space, working on your back and you can very easily get it wrong. Magnetic drills are different, but expensive and lots of messing around to set it up so you're in line with the bolt.

Using a lefthand drill bit and an extractor can get it out, but it's a big bolt and you'll need to push up against the bolt for it to bite and apply so much torque on it to break it loose. Easy to break the extractor.

Did you use an impact gun or a breaker bar to get it off? Can you get a nut on half a thread and weld it on? Use a Dremel and a carbide bit to flatten off the top of the broken bolt, drill a hole in the top as far as you're happy going with a thick enough drill that won't wander and snap off. Pull out some MIG wire, feed it into the hole, enable auto-feed and turn up the shielding gas, shove the tip of the gun against the nut and move out of the way and fill it with enough weld. You'll ruin the copper nozzle, but if it gets you out of a jam. Putting in that much heat will nearly always free the locked threads. Obviously use a decent size nut so you can remove the bolt.

Be careful when welding upside down. Hot spatter will go everywhere and potentially cause life changing injuries. Eye protection. Hair Protection. Face protection is a good idea. And use some electrical tape on your cuffs to prevent it rolling down your sleeves.

If not, can you hack away at the subframe bush to get better access to the bolt. I have a tiny gas torch for making creme brullee. Get some heat on the broken bolt and run 2 nuts on it, then lock them against each other, and get a decent impact on it. Maybe alternate between clockwise and anti-clockwise to free the bolt.

Fingers crossed you can get it out.

[AidXC90]

Originally Posted by Bob Meadows

Call or phone your local engineering supplier and ask for the tapping drill size for the appropriate bolt dia. (information is probably on line as well)
If you can get the final drill hole as close as possible to the required undersize then the remaining threads can be picked out or in a coil- sometimes quite easily.
Quality drills are a must & lubricant- don’t use the stud extractors as recognised: ~
With a little luck you may be able to avoid tapping the thread.
If the hole gets completely mangled it’s not the end of the world!! Come back for a solution but go carefully and you will do it properly.
Copper grease the new bolt- the next owner will love you!
In this situation you seem to have the best advice from members-Good Luck
Bob

Thank you, Bob. I quite agree about the advice I'm receiving. I'm going to start drilling tomorrow but I do have a set of special Snap-On Blue-Point 1020 extractors coming early next week, second hand and missing the smallest bits but I only need the larger ones anyway. They're quite rare I believe. They aren't the usual tapered screw type ones. These are like a square section rod with sharp edges that you hammer a long way into the hole with enough sticking out to get a ratchet onto the end so you get purchase for almost the full length of the hole.
But you are correct in that I'll be using plenty of oil, good drills and lots of patience. I did manage to flood the top of the thread with loads of Plusgas over the last two days as well. I found that the bolt is screwed up inside a sleeve welded into and through the chassis with a bit protruding through into a semi-sheltered space open to the elements. The bolt end sits short of the sleeve end, thereby forming a nice little depression that holds water and rusts the bolt end into the sleeve. Not a good design, but I used this little depression to form a pond of Plusgas to soak the end of the bolt prior to starting work.
So we'll see how it pans out and hopefully the next time I post it'll be with some good news. At least the refurbe'd steering rack is coming back tomorrow.

Thanks again,

Aidan

[AidXC90]

Originally Posted by dstc

I don't like drilling out bolts, too messy, not enough space, working on your back and you can very easily get it wrong. Magnetic drills are different, but expensive and lots of messing around to set it up so you're in line with the bolt.

Using a lefthand drill bit and an extractor can get it out, but it's a big bolt and you'll need to push up against the bolt for it to bite and apply so much torque on it to break it loose. Easy to break the extractor.

Did you use an impact gun or a breaker bar to get it off? Can you get a nut on half a thread and weld it on? Use a Dremel and a carbide bit to flatten off the top of the broken bolt, drill a hole in the top as far as you're happy going with a thick enough drill that won't wander and snap off. Pull out some MIG wire, feed it into the hole, enable auto-feed and turn up the shielding gas, shove the tip of the gun against the nut and move out of the way and fill it with enough weld. You'll ruin the copper nozzle, but if it gets you out of a jam. Putting in that much heat will nearly always free the locked threads. Obviously use a decent size nut so you can remove the bolt.

Be careful when welding upside down. Hot spatter will go everywhere and potentially cause life changing injuries. Eye protection. Hair Protection. Face protection is a good idea. And use some electrical tape on your cuffs to prevent it rolling down your sleeves.

If not, can you hack away at the subframe bush to get better access to the bolt. I have a tiny gas torch for making creme brullee. Get some heat on the broken bolt and run 2 nuts on it, then lock them against each other, and get a decent impact on it. Maybe alternate between clockwise and anti-clockwise to free the bolt.

Fingers crossed you can get it out.

Thanks dstc. I agree that it'll be a very awkward job but I can't weld, don't have a welding machine and no mobile guys want to touch the job. I used a breaker bar which snapped the bolt and it left no thread exposed at all. So drilling and collapsing or extracting the bolt is my only option. There is zero thread exposed and no way I can expose the thread other than cutting off the end of subframe bushing locator spigot which I'm not willing to do, plus of course no welder near me wants to do the job so there's no point in butchering the spigot to expose the bolt end anyway. The extractor set that I'm waiting for might allow me to twist it clockwise and anti-clockwise to work it loose.

My fingers and everything else are firmly crossed.

Thanks

[Bob Meadows]

Ok Aidan it sounds as though you at least have a decent working chance: ~ if you have a blow torch that can be used safely under the car then it helps to expand/contract the fitting and loosen the rust grip- allow to cool & lubricate- we await a positive result! Good luck
Bob

[AidXC90]

Started drilling today with De Walt cobalt bits, first 1.5mm then 3.5mm. All seems to be going okay and straight-ish although you never know just by eye-balling it into a hidden bolt
I've got about 1cm to go and I'll be all the way through the bolt. It's taken me about 1.5 hrs so far and the drilling has been relatively easy thanks to loads of 3-in-1 oil, good quality drill bits and patience but it's the staightness which will make or break the job, and that incorporates a good helping of luck.
I have just started with the 7.5cm bit, which would reach all the way through, but I decided to stop because I want to see the exact size of the drill bits for the extractors coming next week as I don't want to oversize the hole.
I'll also try to use a butane torch - found our kitchen creme brulee torch - to heat up the surrounding metal and try to expand it away from the bolt to crack the rust when the time comes. For now I'll get back to trying to press the wishbone bushes in and preparing the knuckles to receive the new hub bearings etc.etc.

[dstc]

A technique my 1st ever boss (legend) showed me was to rest a 250W soldering iron with a fat tip on a seized and sheared bolt. You need to to hold it against the bolt for atleast 15mins, but the bolt will eventually heat up. It may not be possible to get it glowing cherry red, but it may help. A laser/IR handheld thermometer is perfect for checking temps at both ends.

Desperate times call for desperate measures. Hope you get it out.

*****
Well done. It's a shame you didn't have the extractors ready, the heat from drilling may have released the locked threads. If you can get that creme brullee torch in there and blast it with heat from the inside I am pretty sure it will free the threads. That and rapid cooling with a squirt of WD40.

[ksmi]

Evening Aidan, while you are not drilling, there are folk on here, swear by Duck Oil by Swarfega,if you could fill that space above the bolt,it is supposed to dissolve the rust. When you start drilling again, can you get hold of a volunteer to have a look from different angles to let you know if you are on the strait and narrow, so to speak, Bonne Chance in your quest to remove the bolt!

Best wishes,Keith.

[colinbos]

Better than a Discovery Channel episode this.... Im on tenter hooks !

AidXC90. good going mate, very good going.

We're all with you !