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The old steel bolts seized in aluminium housing challenge


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I extracted /removed  some m8 exhaust manifold studs from the aluminium head of a Renault Alpine V6 with the engine in situ.

I drilled the stud as near a possible central with a 5mm drill and then used a die grinder ( heavier version of a dremel) to slowly grind the stud away and picked the thread spirals out when I just touched the aluminium.  Took nearly 2 hrs per stud  but cheaper than  removing the cylinder head.

good luck

Happy new year

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21 hours ago, cackshifter said:

And also try tapping the stud cold with a hammer if you can, not ridiculously hard, but you are trying to break the corrosion bonds. We are all willing you on.

A decent punch and a good tap with a hammer can break the bonds - also a properly pointy centre-punch given a sharp whack really helps get the drill bit on centre if you're drilling it.

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As a biker, years of working on Japanese machines with cheesehead screws holding everything together means I feel your pain.

A trick I was shown a while ago was to get a strong solution of Caustic Soda and drip it onto the edge of the bolt. Capillary action will run it down the thread and it will dissolve the aluminium oxide locking the stud or bolt in, making it quite easy to release.

As soon as you have got the bolt out flush the hole with vinegar and then lots of water...

Hope that helps.

Simon

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3 hours ago, Junglie said:

A trick I was shown a while ago was to get a strong solution of Caustic Soda and drip it onto the edge of the bolt. Capillary action will run it down the thread and it will dissolve the aluminium oxide locking the stud or bolt in, making it quite easy to release.

I like the sound of that one, might be useful where heat could damage nearby plastics. 👍

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Hello Gentlemen!

Thanks for the additional suggestions. I particularly appreciate your tip and encouraging words cackshifter (What a great name too!! :)and your understanding, Junglie - great idea with the Caustic soda!

On 12/31/2020 at 7:09 PM, cackshifter said:

The warmer you dare get the aluminium, the better, as it expands more than steel. Ideally, hot aluminium, cold steel. So preheat a great idea. You might even try quenching the steel once you have welded onto it. And also try tapping the stud cold with a hammer if you can, not ridiculously hard, but you are trying to break the corrosion bonds. We are all willing you on.

Temperatures here have hovered around -5 C the past few days with spells of wettish snow and very hard freezing, so I am only just today (-3C but sunny and dry) able to start again on the task. Landroversforever requested some pics showing setup and location - so I'm attaching some here... taken , I add, a few days before the snow came. Both protruding studs were since sheared to surface level. Onwards...!!  :) 

Outdoor Garage.jpg

Workspace.jpg

Right.jpg

Left.jpg

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If you've already managed a hole down the middle then just keep going with progressively bigger bits until just short of the hole thread. The remains should then tap round with a small chisel.

HTH

Mo

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Given your temps I think you're really going to struggle to get enough heat into it. If you're trying the welding method again, I'd try getting the blowtorch on it first so that you can actually get some heat in the weld.

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  • 4 weeks later...

Hello Gentlemen,

As promised, this is to bore you stiff… er, I mean…  update you on how things went with this particular challenge. Bad weather slowed progress under my tarpaulin outdoors a great deal hence the delay. But first I’d really like to thank everyone who offered practical advice and suggestions on how to remove steel bolts seized in aluminium, in situ  - albeit here on a VW Passat. This is  such a common problem that it was brilliant to hear how others have gone about the task. Hopefully others may find the ideas shared helpful.  I certainly have. So, thank you!

  Sadly, however, in my own case - despite your encouragement – and much as I hate to admit it, I have had to admit defeat. I simply could not get those bolts to budge. I tried almost all the ideas put forward, but ultimately, I had to face up to the fact that I had too little workspace and access beneath this vehicle; that welding nuts on to sheared bolts directly upwards using a MIG welder was much harder than anticipated (perhaps my welding technique needs reviewing – although the fact that I kept tearing either nuts, bolt stubs, or welded extension blobs off suggests that I actually was getting good penetration); and that I was never able to get my plumber’s torch to put enough heat into either the aluminium or the bolt to break the bond as landroverforever feared. The final straw came as I seemed to be making progress with a 10mm screw-type bolt extractor which finally bit into and seemed to start turning one of the seized bolts … but then snapped off in the bolt! At this low point, she who must be obeyed also pointed out that the vehicle was now urgently required by the family.

  A local workshop advised that despite my misgivings I would be able to drive the vehicle VERY slowly and carefully to them and so I did so with a heavy heart. After a couple of days I received a call from the mechanic who said that he had removed the aluminium subframe in which the bolts were seized in order to tackle them off the vehicle. However, despite plenty of magic dust he too had been unable to free them without causing unacceptable damage to the subframe and threads!! Unfortunately, he does not have a Bridgeport Mill as suggested by vulcan bomber ! The 10mm seized bolts had well and truly corrosively ‘welded’ themselves in. A second-hand subframe has therefore been ordered and will be fitted later this week, allowing new suspension brackets and bushes to be fitted with new bolts.

  So it appears that no matter what technique I might have tried on the gravel beneath the vehicle, nothing was likely to succeed. However, I don’t feel downhearted, because I genuinely did as much as I feel was possible given the constraints. I understand that this is a very common problem with VW and a stupid design failure which makes what should be a simple task both expensive and time-consuming. But I’ve learned a lot trying to address it, not least, as one experienced Youtube mechanic vouched, that not everything you try to keep a job simple will work, in which case you have no option but to replace the whole component as in my case.

  But I thought it might be useful to list out the techniques I attempted – and some others I never got round to – which may well work for others facing similar problems:

 

1.      Where sheared-off bolts project above the surface: weld on nuts. Give sharp blows to the nut whilst cooling to try and break any corrosive bonding and slowly waggle the nut to and fro by hand trying each time to increase outward movement.

2.      As above but instead of nuts, weld on bolts which have had the end to be welded bevelled for better penetration. (Seen but not tried)

3.      Drill centrally into bolts above or below surface. Weld on nuts. Proceed as above. The idea is that weld metal in the drilled hole will give greater penetration and strength.

4.      Where sheared-off bolts are below the surface: weld on successive blobs of metal to create blobby extensions long enough to be given sharp blows and to be able to:

i.                 Weld on nuts

ii.                Apply vice grips

iii.               Apply rounded bolt extractors (i.e. just to ‘grab’)

5.      Drill centrally into bolts using successively larger drills. Hammer in a bolt extractor of some kind – I tried both screw-type and square profile and I even tried torx and spline bits.

6.      Drill centrally into bolts using successively larger Left-Handed Drill bits. The idea is that the larger size(s) could ‘bite’ and spin the bolt out.

7.      Drill centrally and try to drill out the bolts completely. DIFFICULT. Start with centre drill bits. Increase size to just below bolt diameter/close to threads, then pick out remaining threads or try to use a punch to tap them free. (Tried in part then chickened out opting to try a bolt extractor first… which then snapped!)

8.      If a sufficient length of bolt, or ‘blob’ projects and a nut or ‘new’ bolt has been welded to it, try using a good car battery – positive to the bolt, negative to the component. This will get the bolt extremely hot (careful) and can break corrosive bonds. Then try to move the nut. (Seen not tried).

9.      Some techniques recommended welding steel washers to the seized bolts and then welding nuts to the washers – the idea being to provide greater attachment to the bolt via both a washer and nut and perhaps to prevent a seized nut from being welded to a steel rather than aluminium component. It never worked for me. I also tried to use a strip of copper piping shaped into a washer beneath a steel washer so that I could get maximum heat from the welder. This merely resulted in the copper washer melting (!) – clearly not thick enough and it didn’t work either anyway.

10.   An induction heater coil - EXPENSIVE - placed over the sheared bolt or welded blob and nut, heats these up to an extremely high temperature and seems to break corrosive bonds with ease – at least that’s what the Youtube videos I watched showed. (Alternatively try the car-battery technique in point 8 above) Worth a try if you can beg, borrow or otherwise get one. (Seen but not tried)

11.   Having learned the hard way, I strongly recommend:

i.                 Use stubby (non-flexible) centre drill bits to start holes in bolts after centre-punching as accurately as possible: lubricate

ii.                Use cobalt or carbide drill bits (HSS bits will blunt quickly): lubricate

iii.               Give sharp blows to nut/bolt/blobs after welding and allow to cool before attempting to turn

iv.               Go gentle with any impact wrenches and maybe start by hand first if possible – always waggling to and fro: my seized bolts were 10mm diameter – it may be possible to be rougher with larger sizes

v.                Try to use real penetrating oil on the seized bolts if access is possible and give it plenty time to work – perhaps several applications

vi.               Heat: as much as possible;  heat aluminium first (expands faster); or heat steel and quench with water – anything to break bonding

12.   Things I wasn’t able to try but I certainly will in future:

i.                 I use a MIG welder and I don’t have and so wasn’t able to try using a stick-welder as suggested by ballcock. I don’t know if that would result in putting more heat into the seized bolts. But in future I would give this a go. On the shopping list!

ii.                Troll Hunter suggested using left-handed taps smaller than the diameter of the seized bolts and then using left-handed bolts both to create an ‘extension’ on which to attach a car-battery (point 8 above) and to turn the bolt out

iii.               A thicker copper washer or plate to concentrate any weld as suggested by bowie 69 would allow more aggressive welding to the steel bolt without affecting the aluminium

iv.               Using a die grinder – a heavier version of a Dremel - as suggested by taurion, to grind out most of the sheared bolts and then pick out the thread spirals. Definitely worth a go (can’t afford a Bridgeport!!) and on the shopping list.

v.                A strong caustic soda solution dripped onto the seized bolts – as suggested by junglie – to dissolve corrosion would be well worth trying if access was possible

So, there you go. I reckon that with more time (e.g. saturating and dissolving the corrosion) and better workspace, a combination of one or other of these methods would eventually have succeeded. But a man's gotta do... Again, thanks for your help, and I hope someone out there benefits from this ramble in the brambles. Feel free to add ideas if you’re able. :)

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When you have eliminated all possibilities, only impossibilities remain. 
 

therefore did you try throwing a damp tea bag at it?

 

no? Never mind...you’ll never know now.

 

on a serious note, fair play for your persistence to do it...my age makes me use ‘ f*ck it ‘ approach after a few hours when trying to do this sort of thing

 

Hats off to you

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I think, if it were mine, when it gets home, and probably on the one day it's summer, I'd take the bolts out one at time and replace them with duralac or tefgel on the threads or maybe a reasonably mild loctite to stop water getting in and history repeating itself. Thanks for letting us know what happened.

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On 1/26/2021 at 7:36 PM, Badger110 said:

When you have eliminated all possibilities, only impossibilities remain. 
 

therefore did you try throwing a damp tea bag at it?

 

no? Never mind...you’ll never know now.

 

on a serious note, fair play for your persistence to do it...my age makes me use ‘ f*ck it ‘ approach after a few hours when trying to do this sort of thing

 

Hats off to you

 

12 hours ago, cackshifter said:

I think, if it were mine, when it gets home, and probably on the one day it's summer, I'd take the bolts out one at time and replace them with duralac or tefgel on the threads or maybe a reasonably mild loctite to stop water getting in and history repeating itself. Thanks for letting us know what happened.

Lovely! Thank you chaps! From now on the damp tea bag suggestion will be at the top of the list! :) And the 'f*ck it' approach is quickly gaining ground! Now onward to reassembling all the bits on my delayed 110 TD5 rebuild ... 'Tomorrow is another day!' :) 

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Thanks for the update Cluaran, yes common techniques indeed. You learned new ways of trying things that can be applied in the future. I got shot of my 07 plate passat for a similar reason, albeit at the other end of the car. The rear suspension drop arm bushes use a similar alloy into steel with a rubber core setup. I was quoted £500 to renew them as they needed the tracking adjusting as it would wear a rear tyre out every 6000 miles. Several garages tried to losen them on the ramp to ajust the caster/camber???? before saying £500. With weighing up the turbo wanted doing also due to a sticking wastegate and the £2k value of the car i chopped it in.

Experience is knowing when to have a good go and when to give it to someone else.

Pete

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3 hours ago, pete3000 said:

I got shot of my 07 plate passat for a similar reason, albeit at the other end of the car. The rear suspension drop arm bushes use a similar alloy into steel with a rubber core setup. I was quoted £500 to renew them as they needed the tracking adjusting as it would wear a rear tyre out every 6000 miles. Several garages tried to losen them on the ramp to ajust the caster/camber???? before saying £500.... 

Experience is knowing when to have a good go and when to give it to someone else.

Pete

Haha! Suddenly I feel even more less alone! :) And, yes, I probably didn't apply Badger110's 'f*ck it' principle early enough... but I couldn't believe such a simple task would prove so ridiculously problematic. I suspect a similar fate to your 07 plate awaits my vehicle. I hope you're happier with whatever you replaced it with! :) 

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VW -you are talking about a company that doesn't apply grease to steel hubs before fitting alloy wheels.  Or what about the failure of the oil pump driven from the balancer shaft on the 4 cylinder diesels (happened to a colleague at speed on the motorway).  Very overrated . Ok I mentioned diesel once but I think I got away with it.

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