Sorry for having to ask on here. But I doubt I'd get a better range of quality input from anywhere else.

Doing the break job on the rear of the car. A big car and the bolts to remove the calipers are 2 x M19. 3 of them undid nicely but the 4th was taking forever to come out. Had the Halfords Advanced breaker bar on it which is the size of my arm.

Part of me wondered if I should go get the Bosch Impact Wrench/Driver from the loft but I didn't have a 19mm impact socket. The Bosch takes both wrenching and driving with it's unique anvil. So after coming back from the masjid I thought I'd go down to Halfords and grab a 19mm impact bit.

200NM of whacking it and it didn't budge. So back to the breaker bar and it came straight out. Only it didnt, as the impact had sheared the bolt... a rather big bolt. In the panic I called the auto parts store to see if I could source a bolt. He referred me to the auto salvage who was nice enough to open the closed yard for me and allowed me 5 mins, then 3 mins just 20 seconds into the 5 mins.

Thankfully found a bolt that'll make do. Back to the sheared bolt which has half of the thread still in and half out. Dremel out and a bit of shaving the threaded heads to get a adjustable (wider head) wrench on there. So penetrating (well, Weldtite, TF2... like you do) in and some wrenching. It won't budge. Torch out and plenty of heat. Still won't budge, and why would it as the breaker bar with an intact bolt head was just about bringing it out...

Now I'm stuck. Don't wanna make the wrong moves next as I need to get it done by tomorrow. New tools I'm proposing to buy are a Vise Grip and some shock/freeze spray. It brings the temps down to -45 apparently which might just break the bond. I have no access the a welder so putting a piece of metal over is put of the option.

Pls... Thanks

https://www.screwfix.com/p/arctic-produ ... _container

The intact one. Someone mentioned online about heating it all up and then using the ice spray to hear a satisfactory 'pop' as the bond breaks. But that ice sprays says to not use it on heated metal!

It’s a prime example of “the innate hostility of inanimate objects”. In your case, it’s just sitting there, saying “Nah, I don’t wanna. Now what are you go in’ to do?”.

Aaagh! I feel your pain

Plus-gas is a very good freeing agent Shaf' ... WD40 etc will do very little.

Ideally you want heat but lots of heat. I'm pretty sure you won't have bottles available but if you can beg / borrow a MAP gas set up, that might do it.

Also, have you tried screwing it back in a little? Sometimes that'll help remove the corrosion from between the threads.

BTW it's not an M19, that's simply the spanner / head size.

This is a gas I'm using with a Rotherberger Super Fire2 trigger. Next hottest thing up would be an oxyaceteline torch (I think) which is probably too spendy.

Plus Gas, I'll look that up ta. The idea occurred to me to drill a hole inside the bolt (13mm thick bolt). Then use that freezing agent inside it. Hope it frees up and quickly try to undo it with the spanner head I've cut into it.

Without freezing myself up obvs! But... will look at all the options sugessted (so far and future).

Sorry, just re-read your post ... do you know anyone with a welder? If you can weld a nut on, ideally as far down the shank as possible, it'll turn out.

What stu says

Turm the wrong way if possible to " crack"
Immemse heat ( and feeeze... Not sure what it will do but it ia unlikely to do any harm)
Weld to it and extract

Likely need a garage or welder imho.

Thanks all. Yes, do know someone with a welder but he's 10 miles away. Local garages, I'm not too familiar with and my last garage I gave up hope on after he left the brakes unbled then said he nled em 8 times.

So a welder ideally which I was hoping I might get away without, especially since it's a really tight space in there. Might try the extreme heat then extreme cold method in the morn. Maybe even drill a hole inside the nut to spray the cold into.

Will update as to how my plan 'dismantles'

Thanks again everyone and especially for the 'I feel your misery' Frog

Lazarus wrote: ↑Sat Mar 16, 2024 10:10 pm What stu says

Turm the wrong way if possible to " crack"
Immemse heat ( and feeeze... Not sure what it will do but it ia unlikely to do any harm)
Weld to it and extract

Likely need a garage or welder imho.

Jon... This is what led me into thinking I've got a double thread going on. When I was (sensibly) extracting it slowly with the head intact and the breaker bar, I did screw back in a couple of times. Still no joy and the amount of torque required stayed the same. About 250 to 275nm I'd guess!

I wouldn't bother trying to drill it Shaf. It'll likely be a Grade 8 bolt or possibly even 12 ... which means very hard. If you do get a hole down it then it will weaken the bolt making it more likely to snap off which will make the problem worse still.

Ok. Thanks Stu. Won't do that then. Heat and cold it is then before I resort to welding options

Again agree with stu you cannot really drill stainless steel with a hand drill.

Can the caliper mount be removed or is it part of the suspension strut?
Might be easier to take it all somewhere and get it removed on a bench at a garage or engineering place ( £20 aa a guess)

redefined_cycles wrote: ↑Sun Mar 17, 2024 12:06 am Jon... This is what led me into thinking I've got a double thread going on. When I was (sensibly) extracting it slowly with the head intact and the breaker bar, I did screw back in a couple of times. Still no joy and the amount of torque required stayed the same. About 250 to 275nm I'd guess!

I've had that - official name = 'galling' which it is of course! Seems to be due to corrosion causing the bolt threads to partially weld themselves to the bracket threads, then when you undo it metal from the bolt gets pealed off and keeps the bolt jammed solid. I had it on a bolting hold the rear suspension of my BMW motorcycle together - it fought me right to the last thread!

If you can get oxy-acetylene onto it even better

Jon, yes it can't be removed. All one heap of connection to the suspension/track rod etc. I tried the cold treatment with heat before that. Couldn't really get a purchase with the mole-grips.

Used the nut extractor tool that the chap at Screwfix had suggested and informed me he'd had his wheel bolts out with it. My bolt was too tough/soft for that so I managed to snap the rest off.

Phil, yes... Oxy Acetylene is something I often keep thinking of when assessing my level of heat-treating ability. Checking online and it seems I have the best there is (MAAP gas on a Rotherberber 2 trigger) before going up to OA or thatheating coil machine. Been checking what Eric the Carguy would do and it seems my next best thing is to screw it out them retap.

Eurocar Parts have https://www.eurocarparts.com/p/amtech-t ... -553770360 this tap and die kit so might see if it's ok for stainless. Jon, I think my drill might just about cut it (Bosch 18v blue) as lonh as I go grab some decent multi surface drill bits.

Watch this space

Shaf, your bolt won't be stainless. As I said, it'll be grade 8 or possibly 12 which is hardened whereas stainless is actually soft yet can begin to harden when worked.

A cheap gasless mig welder would likely be a better (and cheaper) investment than oxy.

Lomg time since i had oxy but you could only hire bottles.
A mobile welder would be a better bet. I doubt your first ever weld would be good/strong enough

Thanks Stu. Access is really difficult and I'll probably end up welding the bar around the hole (now that I've snapped off the bit sricking out ). Mate has a Snap On welder which I'm sure is gasless so that'd have been an option if we could get into the gap

Lazarus wrote: ↑Mon Mar 18, 2024 10:17 am Lomg time since i had oxy but you could only hire bottles.
A mobile welder would be a better bet. I doubt your first ever weld would be good/strong enough

Good call. Let me google that. Thanks.

Found a mobile welder (hopefully he gets back to me soon) who asked me to send pics. Would this be the right call!!


Gonna ask him to weld this 10mm bolt onto the 12mm. Hoping he has enough exp to not weld to the outer/female end!

Looks to be enough access for someone with exp?



Shall I flatten off the end of the bolt I'm having welded. Or wouldn't that make any difference.

Shaf
I think Stu means use a nut welded on the inside like this-

https://www.youtube.com/shorts/XODPhxEMCzw

https://www.youtube.com/watch?v=PQ0YkPb3oVs

The heat from the welding should also help break the bond in the thread.
Initially just work it back & forwards in order to get some movement in it, then with plus-gas in there it should come out.
Take your time..

You really want to chase out all the threads afterwards with the correct sized tap & make sure any replacement bolts are the correct spec..

As Jase says Shaf - find a nut which is roughly the same size as the bolt and weld the 2 together ... like you're welding a new head on the bolt.

Update time (and thanks again for everyones help):

Rang the 2 mobile welders I could find. One was with a european (well, Polish or Ukranian) accent and I hoped I'd get a good price. Not sure why! Asked me to send pics via Whatsapp and it was obvious it just needed a quick weld so I could wind it out. £150... erm, no thanks

Then spoke to Mini Restoration Centre which is up the road to me. He'd stopped doing mobile welding but suggested that an easy out would do me the trick. Hmmm, looks like the 'holes' getting deeper for me. Got an easy-out/bolt extractor and some appropraite Bosch Hispeed drill bits. The easy out didn't work as I couldn't get a grip on it (and maybe it was just substandard Screwfix generic special).

Mini restoration guy had told me I could borrow his tap to rethread it. Obviously I'm not ready yet but rode up to compare notes and grab some advice. Got 15 miles of cycling in with 1500ft of climbing

Back to car stuff. The chap never had a 14mm tap and checking online it seems they don't come in bog standard boxes. He had loads of 12mm but I wouldn't have been comfy borrowing tools from a working workshop anyway. Next stop, an appropriate sized drill bit to get closer to using a 14mm x 1.5 tap (1.5 is a bit 'hens teeth'). Also, the cutting oil spray I bought for making the hole, he advised against. So Trefolex and learning how to tap it is

Shaff - get a dremel (cheapo ebay copy in any case) and try to grind out as much of the bolt as you can before have a go with a tap. In fact if you are careful and very patient, you might be able to get enough out to pick the threads of the bolt out without tapping - even if you can get the first bit out, that will give some threads for the tap to start on. Be very careful with the tap - if it shears you are totally screwed!