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Discussion Starter · #1 · (Edited)
Doing a removal & replacement job and have got stuck on what thought would be a simple 13+16mm long bolt removal so need bit help especially if have done this exact job.

Right, come across many stuck nuts in my time and after dosing in all the unlocking sprays have got them all off eventually - until I came across this bad boy (pic below). Namely on a 2003 BCB engine MK4 Golf; the nuts+bolts for holding in the Air-Con Compressor consist of two long bolts; lower LHS is simple 16mm, upper is "Double Stud with Hexagon Drive : M10x115 / M8x15" VAG part №: N90633802. The second smaller nut that is on top of this bolt is the M8x15mm BUT is listed as "Shouldered Hex Nut, Self Locking" VAG part №: N02300313 and as you can see it becoming burred in my attempts to remove.

So, for weird (anti-vibration?!) reason the designers at VW Headquarters seemed to have put a 'Lock Nut' (non-Nylon) on a relatively simple long bolt that hold a rail that supports the Power Steering line. Now, there is no other way to get at the a/c compressor for removal or swinging it to side to remove the alternator above the compressor other than removing the first 13mm nut (M8) to get to the secondary 16mm (M10) BUT as the former is a Lock Nut it is doing its job of staying locked!!!

I have used firstly after the dosing of unlocking sprays; a 12 point socket, then read this is a no-no for Lock Nuts and only a Hex 6 pointer socket should be used.

Next step is the very old-school usual stuck nut tricks (hitting with a hammer to 'break' any seals / heating to expand for same reason) BUT this is listed as a LOCK-nut so really asking for advice on this aspect of unlocking a Lock-nut. Area too small to cut it off as will need to replace when putting all toys back in the pram.


So, anyone done this exact job with this EXACT same weird nut+bolt as have undone more bolts than hot-dinners so keep the 'use a spanner and extended ratchet (guaranteed to sheer a Lock nut and you're in a whole other world of knackered nut removal pain!!!)' / 'take it to a garage' or 'sell the car' answers to yourself as only those with the knowledge are being called upon here!!!

BTW Haynes manual had naff-all help & Bentley not a sniff too!

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Sorry if I've missed something, but is the problem just that the bolt won't turn to loosen?

Have you tried a good quality 6 point socket, extension and a breaker bar? Extension is to give you enough space to use the breaker bar. That should be all you need in this situation.

If the nut is rounding off, get a set of bolt extractor sockets and hammer one on, it'll bite into the nut.

Also side note, it's not a weird place for a locking nut, the engine vibrates. Vibrations loosen nuts and bolts. It's perhaps not a NECESSITY, but it's actually quite common practice.
 

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Discussion Starter · #3 ·
Sorry if I've missed something, but is the problem just that the bolt won't turn to loosen?

Have you tried a good quality 6 point socket, extension and a breaker bar? Extension is to give you enough space to use the breaker bar. That should be all you need in this situation.

If the nut is rounding off, get a set of bolt extractor sockets and hammer one on, it'll bite into the nut.

Also side note, it's not a weird place for a locking nut, the engine vibrates. Vibrations loosen nuts and bolts. It's perhaps not a NECESSITY, but it's actually quite common practice.
Ta for reply.

yeah, basic problem is the nut won’t loosen probably because it’s a Lock nut!

used a double hex socket initially but this is prone to burring stuck nuts hence moved on to a quality (Draper Expert) hex socket but literally won’t budge a mm.

breaker bar gosta be careful as nut can literally shear if too much torque with it ‘locked’ in place

bolt extractor sockets is my backup solution if it goes tits-up hence why asking what others have done in same situation before get to that

yeah, well versed in what lock nuts do but rarely come across as when they’re there it’s like a big locked door saying don’t even bother this nut is staying put!!!

someone’s who has really done this would have a anecdotal reply of what worked as as said Haynes just says it’s 2 16mm bolts & Bentleys doesn’t mention either hence posting on IRL VW Forum😉
 

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Hi, I’ve done this, but I don’t remember whether I had any bother with the nut or not as it was a while ago and I’ve dealt with many stuck nuts on my Golf!! I ended up investing in a Mapgas torch and have never looked back - I would be trying some heat in your situation if you can get enough access. I also use plusgas as I’ve found WD40 and others to be usless. I always use 6 point sockets, when loosening a nut/bolt like this, tighten then loosen, repeat many times and eventually you’ll feel it move.
 

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I told you where to get the right sockets for stubborn nuts like this the set i use (multi fit sockets) have not rounded a single nut yet... granted I've rounded a few using the normal metric ones, but one they've been damaged I replace them... also got a set of nut/bolt extractor sockets... don't like to use them as they destroy the bolt/nut they are used on... but they do do the trick... especially if you tap the socket on with a hammer. But those are only used as a last resort.

9 out of 10 times the multi-fit sockets get those partially rounded bolts nuts off.
 

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It's not a lock nut, VW don't use them. It's a serrated nut on the underside of the flange. Not a big deal and you won't find anyone who's had this specific nut give them trouble.

Just tackle it like you tackle any other stuck nut. In awkward places, ALWAYS use a 6 point socket to stop this. Try a 1/2" (basically 13mm in imperial), will be a bit tighter.

Else, easy outs. Else, cut it off.

Make sure you're perpendicular to the nut. If you're not, change the angle. It's already a mess so this will likely need an extractor.
 

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Discussion Starter · #7 ·
Hi, I’ve done this, but I don’t remember whether I had any bother with the nut or not as it was a while ago and I’ve dealt with many stuck nuts on my Golf!! I ended up investing in a Mapgas torch and have never looked back - I would be trying some heat in your situation if you can get enough access. I also use plusgas as I’ve found WD40 and others to be usless. I always use 6 point sockets, when loosening a nut/bolt like this, tighten then loosen, repeat many times and eventually you’ll feel it move.
Thanks for the reply.

Think that as my Golf is the last year of the MK4 the boffins at VW had updated this bolt to a Lock nut probably as it had worked loose & been reported back to HQ but all manuals (Haynes/Bentleys) just have it as 2 16mm ‘normal’ bolts hence no help & not many people actually having to deal with this lock nut situation.

Ta for heads-up on the heating & nut releasing spray possible solutions; heating thing is last in my armoury plus been recommended SeaFoam ‘Deep Cut’ release spray so am spraying copious amounts in this!

Yeah, overall it’s the practical help needed as it’s a pukka Lock nut, not a ‘normal’ stuck nut so think people who’ve actually removed will probably have some wisdom on this ‘designed to stay locked’ nut!

Be interesting to know how a VW Dealership would deal with this obstacle other than getting the hammers / big-toys to remove / break it then replace as I suspect as these aren’t meant to be removed by Design!
 

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Discussion Starter · #8 ·
It's not a lock nut, VW don't use them. It's a serrated nut on the underside of the flange. Not a big deal and you won't find anyone who's had this specific nut give them trouble.

Just tackle it like you tackle any other stuck nut. In awkward places, ALWAYS use a 6 point socket to stop this. Try a 1/2" (basically 13mm in imperial), will be a bit tighter.

Else, easy outs. Else, cut it off.

Make sure you're perpendicular to the nut. If you're not, change the angle. It's already a mess so this will likely need an extractor.
The nut description comes directly from ETKA so it says Lock-nut and having almost burred it got to say I agree with ETKA.

Agree also it’s probably a flanged / serrated nut underneath the nut shoulder which is doing the ‘locking’ not a Nylon or compressed metal thread style locking mechanism which gives hope for removal.

Excellent advise on those other bits & am doing most plus that’s the kinda advice I’m asking for as trying to do job well / carefully first so don’t end up having to drill the broken headed nut out which could be the case if go in all tooled up but no idea what up against / how to tackle and apply too much brute force as can see was edging towards with my burring edges!

Nice one😉
 

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Discussion Starter · #9 ·
I told you where to get the right sockets for stubborn nuts like this the set i use (multi fit sockets) have not rounded a single nut yet... granted I've rounded a few using the normal metric ones, but one they've been damaged I replace them... also got a set of nut/bolt extractor sockets... don't like to use them as they destroy the bolt/nut they are used on... but they do do the trick... especially if you tap the socket on with a hammer. But those are only used as a last resort.

9 out of 10 times the multi-fit sockets get those partially rounded bolts nuts off.
Hey northpole, you trolling me as posted elsewhere (& got many more replies)?!😆
 

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Discussion Starter · #10 ·
I told you where to get the right sockets for stubborn nuts like this the set i use (multi fit sockets) have not rounded a single nut yet... granted I've rounded a few using the normal metric ones, but one they've been damaged I replace them... also got a set of nut/bolt extractor sockets... don't like to use them as they destroy the bolt/nut they are used on... but they do do the trick... especially if you tap the socket on with a hammer. But those are only used as a last resort.

9 out of 10 times the multi-fit sockets get those partially rounded bolts nuts off.
Just ordered that set you recommended VW Brother so takes a few days to be delivered & try out😎
 

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Discussion Starter · #12 ·
It's just serrated, it's not like the one you posted.
Having not got the frigger off yet posted pic of what thought was (squashed thread designed to lock)!

Will post a lovely big pic when it comes off hopefully in one piece so can show & advise the next bold MK4’er who walks this way sometime in the future with equally frustrated feelings🫡
 

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I've just seen your picture in the other thread, have you been trying to undo this nut with the little VAG emergency kit spanner this whole time? Because if so, then that's the issue here.
 

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Discussion Starter · #19 ·
I've just seen your picture in the other thread, have you been trying to undo this nut with the little VAG emergency kit spanner this whole time? Because if so, then that's the issue here.
That is the best reply had in a while; ROFL🤪

Yeah, I only use the one spanner that came with the car & just can’t understand why 99% of other nuts don’t fit!!!🤯

It’s there for the hard of thinking to see it’s a 13mm nut on top of a 16mm nut & frig me the spanner says 13mm!!!

Try reading ALL the words to see if I’ve mentioned other tools other than the one replying…😂
 
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