Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts

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Mon 20 May 2019 17:49
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - bigshorty40

Hi All

In need of some help and advice on what I can do with regards to snapping the heads off the two bolts that secure the front brake discs to the wheel hub on C4? The discs are in real need of a change and the said bolt were welded into the hub, hence why the heads broke off.

Any ideas on what to do would be greatly appreciated.

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Mon 20 May 2019 20:04
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - elekie&a/c doctor
Drill or grind out the remaining bolt. You don’t really need these bolts, as once the wheel is tightened the disc will be kept in place.
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Mon 20 May 2019 20:19
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - bigshorty40
Drill or grind out the remaining bolt. You don’t really need these bolts, as once the wheel is tightened the disc will be kept in place.

Many thanks for the reply.

I'll give them a drill out then. Good to know that they aren't that important though, although it does make you wonder why they actually use them in the first place. The bolts that I broke looked like they were made out of die cast metal, they were so weak.

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Mon 20 May 2019 20:24
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - Galaxy

The bolts are probably part of the way the car is put together during it's manufacture. They hold the discs onto the hubs before the wheels are put on.

If you're just working on a single car that's not on a production line then the bolts aren't really necessary.

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Mon 20 May 2019 20:33
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - bigshorty40

The bolts are probably part of the way the car is put together during it's manufacture. They hold the discs onto the hubs before the wheels are put on.

If you're just working on a single car that's not on a production line then the bolts aren't really necessary.

That makes sense. Cheers for your replies, certainly has put my mind at ease.

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Mon 20 May 2019 21:44
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - RichardW

These bolts are very soft, so easy to drill. You may well find that if you just drill the head off carefully, and the disc is free(*), then when it is removed there will be 2 small stubs sticking out that you can get hold of with pliers or something and screw them out - it's not usually the thread that seizes but the actual head of the bolt to the disc. Whilst not essential it is a bit of PITA to re fit the wheels if the bolts are not there as the disc can spin relative to the hub making getting the wheel bolts in a good game.

* although the discs on our C4 Picasso had to be cut with a grinder and split with a cold chisel to get them off! I did get the screws out however...

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Mon 20 May 2019 21:54
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - gordonbennet

Very glad i didn't answer this one, for some reason i read it that the bolts holding the brake caliper to the hub carrier had sheared, now that would have been a headache.

On either our Subaru or Toyota, the discs have no grub screws holding them in place at all, but instead of wheelbolts they have studs and wheelnuts so no issue as noted by RichardW.

I keep a good old impact driver for those few disc grub screws that turn up on family cars, try and undo them with an ordinary philips they often round off.

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Tue 21 May 2019 06:52
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - Lee Power

I keep a good old impact driver for those few disc grub screws that turn up on family cars, try and undo them with an ordinary philips they often round off.

Exactly this, they need a few good smacks on the head with either an impact driver or pound through screwdriver before you attempt to remove them - catches plenty of diy mechanics out.

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Tue 21 May 2019 09:43
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - RichardW

PSA use TORX heads these days, which I think are better (less chance of camming out).... but you need to clean them out well, and then give them a good hammering to make sure the bit is well seated and the best chance of getting it free.

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Tue 21 May 2019 10:40
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - Andrew-T

The bolts are probably part of the way the car is put together during it's manufacture. They hold the discs onto the hubs before the wheels are put on.

If there are no bolts, when you remove a wheel the disc should fall off the hub - at least that is what happens with any Pug 205 (admittedly an older model but standard PSA for its time). As RichardW says, without at least one bolt holding the disc in place it is harder to locate the wheel as well as the disc when reassembling. But as far as that goes, once the heads are gone and the disc removed, it should not matter about drilling out the shanks as they won't interfere with anything else, and may help a bit. So you only need to drill out if doing the job 'properly'.

Edited by Andrew-T on 21/05/2019 at 10:42

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Fri 24 May 2019 20:17
Citroen C4 1.6 SX Auto - Snapped heads off front brake disc to hub bolts - 3uga

Managed to have the same problem. Took a torch and heated the bolt. Once hot (not red hot) i sprayd wd40 and the heated it up again. After this, I took a flat ccrew driver and tried to unscrewu the bolt. It worked. Heat and extreme temperature variations usualy break the rust bond

Edited by 3uga on 24/05/2019 at 20:17

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