Brake Disc Retaining Bolt Seized
Discussion
As the title says really. After 2 hours of both gentle and aggresive persuasion yesterday, I have a seized retaining bolt on the front nearside disc, that is both ground out and doesn't want to budge.
I have tried all methods suggested online, with the exception of drilling the head out and trying to remove the remaining thread. I've tried the double hammer method, impact driver and also using a hex punch to re-mould the bolt head, but the punch I have isn't steel and therefore is starting to disfigure.
Are there any other options I have left, or do I resort to drilling out the head so I can remove the disc and just go from there? I've also read that this retaining bolt is only there to stop the disc spinning when the car was being manufactured. Is this true, and if so, are they needed? I ask because the Brembos I have bought come with new retaining bolts and would like to use them if I can.
I have tried all methods suggested online, with the exception of drilling the head out and trying to remove the remaining thread. I've tried the double hammer method, impact driver and also using a hex punch to re-mould the bolt head, but the punch I have isn't steel and therefore is starting to disfigure.
Are there any other options I have left, or do I resort to drilling out the head so I can remove the disc and just go from there? I've also read that this retaining bolt is only there to stop the disc spinning when the car was being manufactured. Is this true, and if so, are they needed? I ask because the Brembos I have bought come with new retaining bolts and would like to use them if I can.
It's on an E46 coupe. I'll try and get an image up a bit later, but its a hex screw that has been rounded out, so an Allen won't fit the head any more.
I'm going to go and buy a new set of Allen keys to do the other 3 later on, just getting so frustrated that the first disc I try to remove just wont budge!
I'm going to go and buy a new set of Allen keys to do the other 3 later on, just getting so frustrated that the first disc I try to remove just wont budge!
You can normally attack the screw head with a chisel and pull the disc off. Should be able to get the remainder of the screw out with mole grips. Either that or melt it with a bit of heat (being careful not to damage the bearings). Put the new ones in with some copper grease and they will come out next time.
Impact driver and when it doesn't work, drill them off.
If you leave the thread in then the disc will sit with the thread in the hole and not spin. It's not perfect but saves too much faffing about.
Left handed drill bits are also handy because when you hit a certain point they tend to unscrew themselves due to the heat and vibrations.
If you leave the thread in then the disc will sit with the thread in the hole and not spin. It's not perfect but saves too much faffing about.
Left handed drill bits are also handy because when you hit a certain point they tend to unscrew themselves due to the heat and vibrations.
OlberJ said:
Impact driver and when it doesn't work, drill them off.
If you leave the thread in then the disc will sit with the thread in the hole and not spin. It's not perfect but saves too much faffing about.
Left handed drill bits are also handy because when you hit a certain point they tend to unscrew themselves due to the heat and vibrations.
Thanks for this. I think this is the final plan this week when I revisit it. If they're not serving any further purpose being there, I'll drill off any that are stuck fast. I've already tried the impact driver route and no joy. The problem being that because the head is already rounded off, the impact driver has nothing to grip when turning. If you leave the thread in then the disc will sit with the thread in the hole and not spin. It's not perfect but saves too much faffing about.
Left handed drill bits are also handy because when you hit a certain point they tend to unscrew themselves due to the heat and vibrations.
I'll fire the drill up on Thursday and give it a go.
Robb F said:
The retaining bolt is not useful at all tbh. The disc is stopped from spinning by the four large bolts that go through it and the wheel, although it is useful when you change your brake pads (so not very often).
It also prevents the disc moving when you remove the wheel, with the possibility of crap (corrosion etc.) falling between the disc and drive flange. So quite useful in fact.
Mr2Mike said:
It also prevents the disc moving when you remove the wheel, with the possibility of crap (corrosion etc.) falling between the disc and drive flange. So quite useful in fact.
Is taking an extra 10 seconds to wipe the face when you take a wheel off really worth the effort of struggling with a seized bolt?If you really want to keep it you could simply install a helicoil after you've drilled it out.
Robb F said:
Is taking an extra 10 seconds to wipe the face when you take a wheel off really worth the effort of struggling with a seized bolt?
If you really want to keep it you could simply install a helicoil after you've drilled it out.
If you can remove the caliper, caliper carrier and disc in 10 seconds then certainly, but that's beyond the capabilities of almost everyone I should think.If you really want to keep it you could simply install a helicoil after you've drilled it out.
Once the screw is replaced with copper grease applied to the threads they are easy to remove in the future.
jeoff82 said:
The retaining bolt always seemed to get seized on them BMW's. I always drill them out but if i recall the bolt is quite large so need a largish drill bit.
I'll likely be drilling it out, and have now bought some better quality allen bits to remove the others, so hopefully they won't get stuck either. I have a nice new tin of copper grease to ensure I don't run into the same problems a year or two down the line.lexusboy said:
Are you changing the disc?
If you are, just get a big hammer and smash the disc off from behind, if you've damaged the head of the screw enough it will be soft enough to bend out the way then you should be able to get some molegrips on the stud and remove it that way
fIf you are, just get a big hammer and smash the disc off from behind, if you've damaged the head of the screw enough it will be soft enough to bend out the way then you should be able to get some molegrips on the stud and remove it that way
kadoodledo, remind me NEVER to buy a car from you 
BliarOut said:
lexusboy said:
Are you changing the disc?
If you are, just get a big hammer and smash the disc off from behind, if you've damaged the head of the screw enough it will be soft enough to bend out the way then you should be able to get some molegrips on the stud and remove it that way
fIf you are, just get a big hammer and smash the disc off from behind, if you've damaged the head of the screw enough it will be soft enough to bend out the way then you should be able to get some molegrips on the stud and remove it that way
kadoodledo, remind me NEVER to buy a car from you 
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