Help! I screwed up my Brake Caliper K12R - K-Bikes.com - Excellence in Motion
 
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post #1 of 10 (permalink) Old Aug 2nd, 2007, 9:51 am Thread Starter
 
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Help! I screwed up my Brake Caliper K12R

Guys n Gals,

I put shims on the back of my brake pad to prevent the infamous squeal. Well, with the shims on, I couldn't get my pads back in the caliper. I thought I'd bleed out a bit of juice to compress the pistons. I loosened the 4 bolts on the caliper and started oozing fluid. I tightened them back up. That didn't help. So, I removed the caliper (held on by 2 bolts) and compressed the pistons using my slip-pliers. Now, everything is back together, and when I squeeze the hand-brake, fluid is oozing out of my caliper.

What's the solution? Did I tear a seal? I don't know what's inside the caliper that could be messed up. Any help would be greatly appreciated. I can't get it to the dealer until 30 AUG.

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post #2 of 10 (permalink) Old Aug 2nd, 2007, 10:25 am
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Quote:
Originally Posted by Captain K12R
I loosened the 4 bolts on the caliper and started oozing fluid. I tightened them back up.
Any particular reason why you didn't simply open up the bleed screw instead? Or simply reinserting the brake pads part way (sans shims) and using them to lever the pistons all the way back into their bores would have been a better method.

Can't say with your model, but the factory service manual for mine explicitly says not to separate the caliper halves, which it sounds like you did by loosening the non-mounting bolts.

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post #3 of 10 (permalink) Old Aug 2nd, 2007, 10:30 am Thread Starter
 
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Quote:
Originally Posted by carnadero
Any particular reason why you didn't simply open up the bleed screw instead? Or simply reinserting the brake pads part way (sans shims) and using them to lever the pistons all the way back into their bores would have been a better method.
Cause I don't know what the heck I'm doing.
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post #4 of 10 (permalink) Old Aug 2nd, 2007, 10:41 am
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You didn't read the Clymer manual before you started!

The calipers are made in 2 halves machined to high tolerance and you're not supposed to separate them. There are one or 2 O rings in there and/or you might have some dirt trapped when you bolted them back up. I suspect the O ring(s) may have dropped down, might even be lying under the bike. There are NO gaskets. I don't think BMW/Brembo consider the internals of a split caliper a serviceable item. That's not to say that they can't be fixed.

With hindsight, I don't know why BMW/Brembo didn't use a different bolt head like torx on there so you don't get confused with the caliper bolts. But then it seems you made a conscious decision to split the caliper anyway.

It sounds from your post that you made a stupid mistake and we've all made them, but may not have the skills to work on a critical brake part which your life depends on. I strongly recommend you have the caliper checked by a brake specialist or at least a buddy with brake/engineering skills. I suspect a BMW dealer won't touch it and want to sell you a new caliper.

I've split a caliper and provided you didn't do any damage bolting the halves back up your situation may be recoverable but I'd be nervous giving you any further advice on safety grounds.



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post #5 of 10 (permalink) Old Aug 2nd, 2007, 10:54 am Thread Starter
 
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Originally Posted by voxmagna
You didn't read the Clymer manual before you started!

The calipers are made in 2 halves machined to high tolerance and you're not supposed to separate them. There are one or 2 O rings in there and/or you might have some dirt trapped when you bolted them back up. I suspect the O ring(s) may have dropped down, might even be lying under the bike. There are NO gaskets. I don't think BMW/Brembo consider the internals of a split caliper a serviceable item. That's not to say that they can't be fixed.

With hindsight, I don't know why BMW/Brembo didn't use a different bolt head like torx on there so you don't get confused with the caliper bolts. But then it seems you made a conscious decision to split the caliper anyway.

It sounds from your post that you made a stupid mistake and we've all made them, but may not have the skills to work on a critical brake part which your life depends on. I strongly recommend you have the caliper checked by a brake specialist or at least a buddy with brake/engineering skills. I suspect a BMW dealer won't touch it and want to sell you a new caliper.

I've split a caliper and provided you didn't do any damage bolting the halves back up your situation may be recoverable but I'd be nervous giving you any further advice on safety grounds.
I appreciate your frankness. Not to worry, I'll not touch it again. I will have a professional tech take care of it. I really don't like wrenching the BMWs. As you say, it's a life threatening item.

Thanks,
D
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post #6 of 10 (permalink) Old Aug 2nd, 2007, 11:21 am
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Listen, if you didn't make the mistake you would have never have known how brake calipers are made.

I've made some real bone head mistakes as well. Doesn't stop me.

Shouldn't stop you from wrenching if that's what makes you happy.

I blame BMW for not giving up a proper radial mount monoblock caliper (no screws)!!!!
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post #7 of 10 (permalink) Old Aug 2nd, 2007, 1:47 pm
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I second that. Most my education is from screwing stuff up. Don't be discouraged!

-=grif=-
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post #8 of 10 (permalink) Old Aug 2nd, 2007, 3:08 pm Thread Starter
 
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Thanks guys. Question for you--do you think I can ride it to the dealership just using my rear brake? Of course, the techies at the dealership are saying under no circumstances ride the bike. I think it's just for liability purposes. I HATE the thought of trailering it.
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post #9 of 10 (permalink) Old Aug 2nd, 2007, 3:33 pm
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Quote:
Originally Posted by Captain K12R
do you think I can ride it to the dealership just using my rear brake?
Probably not a good idea. 1) Reduced stopping distance, and given the behavior of motorists in general, being able to stop quickly is a must, 2) if it leaked anyway and fluid got onto something that's spinning, it'll probably get thrown all around, and brake fluid loves to assault painted surfaces.

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post #10 of 10 (permalink) Old Aug 3rd, 2007, 7:28 am Thread Starter
 
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Originally Posted by carnadero
Probably not a good idea. 1) Reduced stopping distance, and given the behavior of motorists in general, being able to stop quickly is a must, 2) if it leaked anyway and fluid got onto something that's spinning, it'll probably get thrown all around, and brake fluid loves to assault painted surfaces.
Thanks. My bike has been trailered
Boy, do I feel neutered.
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