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Discussion Starter #1
Hi,

I’d just managed to put my self in a difficult situation. I was trying to remove the left front brake calliper (Brembo) on my phase I GTV 3,0, and the upper fastening screw was for some reason not completely tightened but was stuck half way in. No matter what I did it could not get it loose (drowned it in oil over night, using heat, hammer, power ratchet etc.). As a last resort I used force and of course the screw snapped :(. Hmmm, what to do? I thought that if I removed the brake disc the calliper also would come lose (the lower fastening screw was removable), but when I tried to remove the fastening pin to the disc it, guess what.... also snapped!! :cry: – see attached pictures.

Well, this is where I stand at the moment and I don’t know what to do next. Is it possible to remove "the whole package" (disc, calliper etc.) and take it to some one that can help me drill the screws out, or what can I do.....?

Grateful for inputs on this.

Best regards

/Olle
 

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So what is holding the disc and caliper on?

The bolt for the disc is just to hold the disc in place, as it's sheared off the disc would now be free to come off - disc probably is stuck on due to rust and needs a good hit from the back with a mallet etc

I guess the disc cant come off completely because the caliper is there but since you've also sheared that mounting bolt off then the caliper should have enough space to move and come off.

Have you taken the brake pads out?
 

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First off, isn't there another threaded hole in the hub for the disc retaining bolt?
Have you got the other bolt out of the caliper?
Remove the caliper and then remove the disc (you'll need to knock the disc off) and check, I thought there were two of these holes opposite each other on the hub, if so, just get a new retaining bolt and ignore the other.

If not, if there's enough hanging out, try a stud extractor, but I doubt there will be so get a good set of drill bits, drill out the broken bolt carefully, start with a smaller bit, say 5mm, then work up, try and get the first bit straight down the middle, with patience, you'll get it out.
This bolt hold the disc to the hub has four helpers, the four wheel bolts, so once the wheels back on, with or with out this little bolt, the disc's going nowhere.

As for the other broken bolt in the caliper, I'd hazzard a guess that it wasn't the right bolt in the first place, it usually has a fairly fine thread and that one in the pic looks wrong (I can not remember seeing a washer on any of these bolts either), if it was jammed without fully screwing in, the only thing that'll stop it half way down is the tread on the bolt and the caliper not matching.
If this is the case, this will be a problem, as it's already wreaked the thread in the caliper, the wrong threaded bolt will have started to cut a new thread in the caliper.

You could try drilling it yourself or take to an engineers, see if they can drill it out and put an thread insert in it, but as it's the brake I'd not want to chance anything and replace the caliper.
 

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Discussion Starter #5
Hmmm, so since the fastening pin snapped there is nothing holding the disc, which makes sense. And the same goes for the calliper bolt, there are of course no threads in the calliper. Let me go out to the garage and use some good old ultra violence on the brake disc and see what happens......

Thanks for your quick replies guys, I’ll keep you updated on this....

/Olle
 

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I think Goudy's right - it look as though somebody has used the wrong bolt for the caliper mounting, with a different pitch to the thread in the caliper, & there shouldn't be a washer there. If that's the case, as Goudy says, the thread in the caliper will have been damaged. The risk now is that it will strip completely when you fit the correct bolt; in any case, you will have less thread in engagement than the fastening was designed to use, not a good situation. It may be possible to get a thread insert fitted, provided that there's enough metal around the hole, which does appear to be the case here - for guidance, take a look here:

http://www.helicoil.in/pdf/HeliCoil Catalogue.pdf

A properly-installed Helicoil will result in a stronger thread than the original; however, if in any doubt, replace the caliper - you can't afford to compromise on safety.

Now the good news: don't worry about the disc retaining screws. All they do is stop the disc dropping off when the wheel's removed - I've driven several cars without them with no problems.
 

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I agree with you Dave on the Helicoils, they use them to hold some pretty heavy duty stuff, and as I think the caliper is alloy, a steel insert fitted properly wouldn't be any weaker than before.

The disc retaining bolt holds the disc on while you fiddle with the pads and with the nipple on the end, helps line the wheel up with you fit the wheel bolts.

So, try and sort the disc retainer bolt out, but if no luck, don't worry the wheel bolts will hold it all on, take the caliper off, take it to an engineer/engine reconditioner, they'd get the broken bolt out and Helicoil the thread.
Then get hold of the correct bolts, the engineer may be able to help you, as they'll know what thread they fitted with the Helicoil and you can take the length off the other bolt, when you bolt it back together, use thread lock on the caliper bolts and torque them up correctly, don't over tighten them.
 

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Discussion Starter #8
Update,

So far so good, a few hits with the hammer on the brake disk did the job. The disc and the calliper came clean off - big relief, thanks again for all advice. I had to cut the brake hose since that seemed quite stuck to, and I didn’t what to break another bolt today :rolleyes:. I have already bought braided lines anyhow (grateful for advice to get the old lines out in one piece). I still have the problem with the bolts though, but if I can’t manage to get them out I’ll just leave the calliper to a mechanic to do it for me.

Another question, how do I get the pads out? Do I need so split the calliper, unscrewing the four bolts on the inside of the calliper? Or can it be done in a simpler way, my manual seems to cover only the "non-Brembo" callipers (this is probably a quite simple thing, but since there are no such a thing as a stupid question.... :)

Thanks again, how did amateur mechanics manage before internet...?

/Olle
 

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The pads are extremely easy. In pic 2 you can see 2 long pins (pad retaining pis) holding in a spring clip above the pads, these pins need to be tapped out from the side of the caliper (I think from outside to inside), the spring clip will come off and the pads can come out.

If you dont have a punch then you can use a flatten nail or similar to tap out the pad retaining pins

The pads will be tight as the pistons in the caliper are pushing them against the disc - if the disc has a small lip the pads wont come straight out. If you gently push the pad away from the disc then the pistons will go back inside a bit and the pad will be loose...........but take care since you've remove the brake pipe then brake fluid would squirt out from the hose and make sure you done get any brake fluid on paint etc as it will strip the paint off, try to keep it off the caliper too
 

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Don't take this the wrong way mate but so far you have asked very basic questions on brake maintenance. you really need to be more clued up when working on something so important. Is there noone who can give you a hand who has done this before? You don't want to stack the car and risk hurting yourself (or indeed others) of a lack of knowledge.

As I say, I'm not being a git, it just that brakes are so important.
 

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There are two pins, as seen it pic 2 that run top to bottom through the top of the pads, you can see the ends of them in pic 1, if you turn the caliper over, you'll be able to see the other ends of these pins, they should unscrew like long bolts with an allen key. There may be gromets over the heads of these pins to keep the dirt out, prize the out.
Note the way the anti rattle shim fits under these pins (seen in pic 2 between the pins) for refitting. Once you've removed the pins and shim, the pads should pull through towards you. They may not pass the lip in the edge of the disc, so you may need to push the pads/pistons back a little with a screwdriver.

Note, there may be/should be split pins that stop these pins from falling out, I can't see them on the pics, but I think they should be. Check the shaft of these pins, if there are small holes in them, you'll need a couple of small split pins when you rebuild them.

As for the broken bolt, a good engineer will have no problem with repairing it, but make sure the thread is repaired (helicoil) and the new bolt fits right, if it's to long it will go through and hit the inside of the disc.

When you come to rebuild it, PM me for a rebuild guide.
 

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Don't take this the wrong way mate but so far you have asked very basic questions on brake maintenance. you really need to be more clued up when working on something so important. Is there noone who can give you a hand who has done this before? You don't want to stack the car and risk hurting yourself (or indeed others) of a lack of knowledge.

As I say, I'm not being a git, it just that brakes are so important.
The why I look at it, if mans distant cousin from Kwikfit can repalce brakes, I wild Gibbon can manage it!
 

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Discussion Starter #14
Thanks again guys,

Mitch166: No worries, I kind of expected that comment. The thing is that I'm not a complete rookie as a mechanic, but I have done most work on bikes (or BMW:s ) before. The car is on axel stands for the winter and now is a good opportunity to do maintenance and to gain some experience. I now brakes are important and that's why I ask all (some perhaps basic) questions to make sure I get it right. Next time I know how it's done.

/Olle
 
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