Carrier bolt sheared and stuck in hub

Carrier bolt sheared and stuck in hub

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Benjy911

Original Poster:

544 posts

145 months

Sunday 2nd August 2015
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So today I set about changing the front discs and pads on my S3 and so far after 6 hours I have one side apart and am stuck!

As I was changing the disc I set about removing the calliper carrier, the top bolt came undone fine however after probably too much brute force the bottom bolt sheared off. It was then that I realised I could just swing the carrier down with some more force and remove the disk grumpy

After this slight drawback I set about drilling the bolt out...4 drill bits down, 5mm into the bolt and I realised it wasn't going to be that simple so I went off and had a think. On return I swung the carrier down a bit more and realised that the bolt was actually seized within the hub where it attaches to the car, which is totally smooth and not threaded like the carrier. With this new found knowledge I've tried prising the carrier off with a breaker bar between it and the hub, lots of smacking with a hammer and also heat, none of which have got the bd off!

Has anyone had this issue and if so how did you solve it?


andyiley

9,101 posts

151 months

Sunday 2nd August 2015
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Assuming I am correct in understanding you, you are saying that the parelell shank of the bolt is seized in the hub.

So that if you turn the carrier further down, the end of the bolt (seen through the carrier) stays still & in fact the carrier will unscrew itself (to a part of a thread by the looks of it) until you run out of space.

If that is right have you tried unscrewing it as far as possible, and then sliding a washer (with a cut out to go round the bolt) between the carrier & hub, and then reversing the rotation to screw the bolt shank out.

You may also need to apply heat/penetrating fluid/hammer action to assist it.

Benjy911

Original Poster:

544 posts

145 months

Sunday 2nd August 2015
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Your understanding is indeed correct, thank you for your suggestion.

I'll try it tomorrow and report back, the gap is quite tight as it'll only swing down to about the 6 o'clock position but some force might squeeze one in!

Benjy911

Original Poster:

544 posts

145 months

Monday 3rd August 2015
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So far no luck! I've been trying most of the morning and it just won't budge. Unfortunately there isn't space for a washer so I've tried a puller but that just ended up slowly pulling through the hub, I've also tried more heat but it seems totally stuck in there.

I'm starting to wonder if someone has put locktite or similar on the bolt, but you'd have thought that would have melted off with the heat? Wish I hadn't started doing them now!

andyiley

9,101 posts

151 months

Monday 3rd August 2015
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You say you are using heat, by what means & how much?

To have good effect, you virtually need to get steel glowing hot, but this looks like an alloy hub, so be careful if it is, if not, you really need to get some SERIOUS heat on it & it WILL go, a blow-torch is not normally enough except in perfect still conditions.

Huff

3,140 posts

190 months

Monday 3rd August 2015
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Can you file the stub clean enough to slide the carrier off what remains of the bolt? Things will be easier if so.

I would then clean-up the bolt stub with wirewool/dremel and find someone with a MIG welder and have them weld an M10 or sim nut to the stub. Wind it out immediately while hot - it should come free owing to the welding heat dumped into the stub. I've had broken studs out of more-awkward things (eg snapped flush with engine block...) before by this method. If not at first try, hit the migged stub with a torch, try again, - until it comes free.

Benjy911

Original Poster:

544 posts

145 months

Tuesday 4th August 2015
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Thanks for the suggestions, but I've given up and taken it to a garage!

For heat I was used a butane and propane mix, probably not hot enough though as I never got it glowing?

In terms of sliding the carrier off, the bolt was threaded onto the carrier and would only swing down 90 degrees so wasn't going anywhere. The hole in the hub was unthreaded so in theory it should have just slid out once the head had sheared off, however it appears something has got it stuck. Corrosion, sealant, I'm not sure, but the garage can struggle on!

trickywoo

11,700 posts

229 months

Friday 7th August 2015
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Every time I do a disc swap on a new (to me) car this element always worries me.

I always refit with copper grease and torque to the specifications. If the factory and everyone working on the car did this there would be no such worries.

Hope the garage sorts it without too much fuss / expense.

Polome

541 posts

124 months

Saturday 8th August 2015
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This looks very similar to an A4 I did recently...I cut the head off the bolt ( socket head cap screw) with a grinder . ( a hacksaw would do it too) so I was left with the caliper carrier in my hand . It was easy enough then to grip the remaining protruding part of the studbolt with a stilson and it came out quite easily ...when the head of the bolt is chopped off its only the tightness of the thread you need to overcome ,not the original torqued setting so it usually easy to come out. Good luck

Benjy911

Original Poster:

544 posts

145 months

Saturday 8th August 2015
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To update, the garage got them all out and put my new discs and pads on all round as I'd got quite fed up doing it and just wanted to drive it again! All the bolts needed lots of heat to remove and far more than I could have done so it was probably lucky I didn't snap any more off! They reckoned that the car had probably been stood in a field or similar when new for a while as they were all very corroded into the hubs.