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Discussion Starter · #1 ·
I just got me hands on a set of 4 pad callipers for my 998.

I'm going to give them a good clean now as I inspect them properly.

Usually I clean callipers with break clean spray and remove the pistons, inspect the seals and bores as well as the pistons, and tidy up the whole thing.

The question now... As they are not mono blocks, do you ever take one calliper apart. They split in half right, held together with three bolts.

Is this a big no no or can I do this without cursing it?

Cheers
 

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I just got me hands on a set of 4 pad callipers for my 998.

I'm going to give them a good clean now as I inspect them properly.

Usually I clean callipers with break clean spray and remove the pistons, inspect the seals and bores as well as the pistons, and tidy up the whole thing.

The question now... As they are not mono blocks, do you ever take one calliper apart. They split in half right, held together with three bolts.

Is this a big no no or can I do this without cursing it?

Cheers
I have taken apart 3 bolt - 999 4pad calipers a couple times. No big deal, except you cannot get replacement seals so don't screw them up. Just one little o-ring between the halves. Quite nice hard anodized aluminum pistons on the ones I took apart. They cleaned up easily. I used WD-40 to clean everything up just in case brake clean might hurt the rubber parts.

I had to use an educated guess for the torque on the bolts, don't remember what it was though.
 

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Discussion Starter · #3 ·
I have taken apart 3 bolt - 999 4pad calipers a couple times. No big deal, except you cannot get replacement seals so don't screw them up. Just one little o-ring between the halves. Quite nice hard anodized aluminum pistons on the ones I took apart. They cleaned up easily. I used WD-40 to clean everything up just in case brake clean might hurt the rubber parts.

I had to use an educated guess for the torque on the bolts, don't remember what it was though.
Ok thanks, I think I'll try this!
 

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+1 on cleaning calipers w/ WD40. I installed new pads a few weeks ago and decided to clean the calipers too. I did use a brake cleaner, then used WD 40. Came out nice and clean-however they were a PITA to clean on the bike, you won't have that problem.
 

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Discussion Starter · #5 ·
Sweet, WD40 it is!

The 4 pad callipers felt a lot lighter too. Maybe that's just my imagination.

Can't wait to try them out... I've got a 19x18 MC on its way too, I had a 19x20 before.
Next meeting on the 26th!
 

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Your timing is impeccable. I just posed this question to my dealer yesterday.

2005 999S. I really think that the pads are not releasing as well as they should. I asked the dealer about seals for the calipers. He said that they are not available and he cautioned me about pulling the calipers apart. He said to remove the calipers from the bike, pull the banjo and bleeder, and flush them out with brake cleaner. He said that it's the piston seal that actually helps the piston to release back into the caliper. I am hoping that cleaning them up on the outside will solve the problem.

Lar.
 

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You probably have brake dust build up on the pistons. I don't think I would spray brake clean "in" the caliper.

It's much easier to clean everything by taking it apart, but WD-40 works pretty good even with them assembled. If you have an air compressor and a rubber tipped blow gun you can pop the pistons out by shooting air in the caliper line opening. If you do this, BE CAREFUL, FIRMLY hold a rag over both pistons in the half you are working with your hand. One will always want to pop out before the other. The key is to get both of them almost out of the bores at the same time. If you get carried away and one is not restrained, it will fly out, it will spray brake fluid everywhere, it will hit something at high speed and may mess up the pistons after it flies across your work area.

If a seal looks funny after you gently pry them out, flip it over, it will use a different, previously unused corner of the seal.

Don't force the pistons back in the caliper dry, coat it with clean brake fluid at minimum.

If this fails, ebay.
 

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Your timing is impeccable. I just posed this question to my dealer yesterday.

2005 999S. I really think that the pads are not releasing as well as they should. I asked the dealer about seals for the calipers. He said that they are not available and he cautioned me about pulling the calipers apart. He said to remove the calipers from the bike, pull the banjo and bleeder, and flush them out with brake cleaner. He said that it's the piston seal that actually helps the piston to release back into the caliper. I am hoping that cleaning them up on the outside will solve the problem.

Lar.
Yeah, it's the resilience of the rubber seals on the pistons that causes them to retract after brake application.

I remember reading about the dangers of splitting calipers. I don't know if it's fact or fiction though. If you can find an O ring supplier, you can probably get a replacement when you split the calipers.
 

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If a seal looks funny after you gently pry them out, flip it over, it will use a different, previously unused corner of the seal.

Don't force the pistons back in the caliper dry, coat it with clean brake fluid at minimum.

If this fails, ebay.
I would find replacement seals instead, and I think flipping it over may not be a good idea. There is a special grease that is used for brake pistons, but I don't know where you get it.
 

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I have taken apart 3 bolt - 999 4pad calipers a couple times. No big deal, except you cannot get replacement seals so don't screw them up. Just one little o-ring between the halves. Quite nice hard anodized aluminum pistons on the ones I took apart. They cleaned up easily. I used WD-40 to clean everything up just in case brake clean might hurt the rubber parts.

I had to use an educated guess for the torque on the bolts, don't remember what it was though.
I'm not sure if WD-40 is compatible with brake fluid. I'd read up on that before using it.
 

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Just a personal view, but all this "make do and mend" stuff doesn't sit easily when applied to the #1 safety-critical component on the bike?
Using some of the workarounds listed here might be ok, but could be an expensive lesson

I've heard some surprisingly low prices listed for new calipers from Brembo, maybe worth checking?
 

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Just a personal view, but all this "make do and mend" stuff doesn't sit easily when applied to the #1 safety-critical component on the bike?
Using some of the workarounds listed here might be ok, but could be an expensive lesson


Obviously, if you don't have the tools, or a good grasp of mechanics or a torque wrench, don't screw with you brakes. However, many people change their own oil, can you imagine what kind of wild ride would ensue if the plug came out while at speed? How about an improperly torqued sprocket? Any maintenance on a bike if not done properly can result in injury. Get the tools, the books, and give it a go.

Mark
 

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You've missed my point Mark. No problem doing any tasks if you have the correct tools and spares etc.....agree with you
But some of the concepts listed here about flipping seals "if they look funny", using an O ring from some uncertain source because the OEM replcement is unavailable, and guessing at the torque setting......well that doesn't sound like a smart way to service brakes?
I'm sure you'd get away with it most times, just raising a note of caution, that's all;)
 

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Discussion Starter · #14 ·
All good points people.
I'll carefully clean the callipers on the outside, I won't take them apart.
cheers
 

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All good points people.
I'll carefully clean the callipers on the outside, I won't take them apart.
I'd consider taking them apart a no no too.

you don't need any compressed air etc. to get the pistons out a bit,
just get the calippers of the fork and leave them connected to the master,
then start pumping carefully until you got them were you want.

than clean everything up with warm soapy water and a tooth brush.
 

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Rebuilding calipers is not rocket science. They are just 4 square cut o-rings. I have rebuilt calipers on my racecar and now on my motorcycle. People rebuilt calipers for years, it is about the most simple thing you can do mechanically. It is only lawyers causing issue and frightening people. I would rather do something myself then trust somebody else. You can twist an o-ring if you force an un-lubricated piston in to the bore.

But, yes if you don't feel comfortable doing this, buy new calipers, that is your only alternative.

I was not suggesting to leave WD-40 inside the caliper, but I think it would be kinder to o-rings that are exposed to outside part of the caliper than brake clean. What is worse to a seal, abrasive brake dust or WD-40?

The "grease" I have seen lubricate pistons is a silicone based lube that looks exactly like what is sold to lubricate sway bar (anti-roll bars) or as dielectric grease. In the "old" days manuals would tell you to soak the seals in brake fluid before assembly.

As for splitting calipers, especially 4p4p 999 calipers, there is nothing to it. The halves are not machined in a way that they are some sort of select fit or press fit to each other. They are flat surfaces with no located pins, dowels or any other such things.

OK, the halves are not really flat, because as the cutter used to machined the caliper surface half hits the material it skips a bit leaving a slight high spot along all leading edges of the caliper half. So being anal as I am, I clean off this high spot with a high quality file or a piece of emery cloth mounted on a glass surface. It will be flatter and fit tighter than any caliper that came from Brembo.
 

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Rebuilding calipers is not rocket science. They are just 4 square cut o-rings. I have rebuilt calipers on my racecar and now on my motorcycle. People rebuilt calipers for years, it is about the most simple thing you can do mechanically. It is only lawyers causing issue and frightening people. I would rather do something myself then trust somebody else. You can twist an o-ring if you force an un-lubricated piston in to the bore.

But, yes if you don't feel comfortable doing this, buy new calipers, that is your only alternative.

I was not suggesting to leave WD-40 inside the caliper, but I think it would be kinder to o-rings that are exposed to outside part of the caliper than brake clean. What is worse to a seal, abrasive brake dust or WD-40?

The "grease" I have seen lubricate pistons is a silicone based lube that looks exactly like what is sold to lubricate sway bar (anti-roll bars) or as dielectric grease. In the "old" days manuals would tell you to soak the seals in brake fluid before assembly.

As for splitting calipers, especially 4p4p 999 calipers, there is nothing to it. The halves are not machined in a way that they are some sort of select fit or press fit to each other. They are flat surfaces with no located pins, dowels or any other such things.

OK, the halves are not really flat, because as the cutter used to machined the caliper surface half hits the material it skips a bit leaving a slight high spot along all leading edges of the caliper half. So being anal as I am, I clean off this high spot with a high quality file or a piece of emery cloth mounted on a glass surface. It will be flatter and fit tighter than any caliper that came from Brembo.
+1 on this one ... Stop treating these things like they are made out of gold. Care is obviously a must when one is dealing with calipers ... but other than that ... its a standard piece ... nothing special to it ...

Migrane
 

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I see no reason to pull the halves apart. That is just needless things to take apart that could cause an issue. You can pull out the pistons and seals without the extra step. As for actually doing it, Brembo considers all of their calipers and most of their master cylinders as non-rebuildable.

Should you or shouldn't you is up to you. I have done it to a set of calipers already with no ill effects. Would I do it again? More than likely.
 
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